Analysis of the characteristics of meltblown cloth

Meltblown nonwovens are mainly used as composite materials, filter materials, thermal insulation materials, sanitary products, oil-absorbing materials, cleaning cloths (wipes), battery separators, etc. and other fields. As can be seen from Figure 1-32, in foreign countries, meltblown nonwovens are mainly used as two-step SMS materials and medical and sanitary materials and covering materials. In addition, wiping and absorbing materials, filtering and barrier materials are also meltblown cloths important use. The specifications of meltblown nonwovens for various typical uses are shown in Table 1-8, and the application fields and shares of domestic meltblown nonwovens are shown in Table 1-9. (1) Medical protection Due to the high hydrostatic pressure resistance, good air permeability and filtration effect of the material compounded by meltblown cloth and spunbond cloth, especially the material compounded with membrane, it has good barrier properties and is suitable for non- The filtration efficiency of oily particles can reach more than 99%. For example, medical protective clothing made of composite materials with a quantitative specification of 60-100g/㎡d can effectively block microorganisms, particles and fluids. protective effect. (2) The melt-blown composite material with electrostatic electret treatment for air filtration materials has low initial resistance, large dust holding capacity and high filtration efficiency when used for air filtration. The filtration efficiency of the diameter can reach 99.9%, and the resistance is only 117.7Pa (12mm water column). It is widely used in air purification in electronic manufacturing, food, materials, chemicals, airports, hotels and other places. Meltblown nonwovens are mainly used as composite materials, filter materials, thermal insulation materials, sanitary products, oil-absorbing materials, cleaning cloths (wipes), battery separators, etc. and other fields. (3) Materials for liquid filtration Melt-blown nonwovens can also be used as liquid filtration materials, which can filter particles with a particle size of 0.22~10um. Such as bacteria, blood and macromolecular substances. Mainly used in the filtration of photoresist in the electronics industry, the filtration of pharmaceutical, biological and synthetic plasma products in the pharmaceutical industry, the filtration of beverages, beer and Tang Jiang in the food industry, the fine filtration of electroplating solutions, the filtration of water purification in water plants, and the purification and filtration of tap water. Point splitting water hydrogen production device, environmental wastewater filtration, etc. (4) Meltblown nonwovens for thermal insulation materials have the characteristics of large specific surface area, small voids and high void ratio. For example, a meltblown nonwoven fiber with an average diameter of 3um [equivalent to an average linear density of 0.0638dtex (a fineness of 0.058 denier)] has a must-change area of ​​14617cm2/g, and an average diameter of 15.3um [equivalent to the average fiber The specific surface area of ​​the spunbonded nonwoven fiber with a linear density of 1.65dtex (fineness of 1.5 denier) is only 2883cm2/g. Since the thermal conductivity of air is much smaller than that of ordinary fibers, the air in the pores of the meltblown nonwoven makes its thermal conductivity smaller, and the heat loss through the fiber material of the meltblown nonwoven is very small, and The still air on the surface area of ​​countless microfibers prevents the heat exchange due to the flow of air, so it has a good heat insulation and heat preservation effect. Polypropylene (PP) fiber is the type with the smallest thermal conductivity among the existing fiber materials. After special treatment [such as adding 35% high-spec (coarse denier) PET three-dimensional crimped fiber], the melt-blown thermal insulation flakes made of PP fiber , the thermal insulation performance is 1.5 times that of down and 15 times that of ordinary thermal cotton. Especially suitable for making ski suits, mountaineering suits, bedding, sleeping bags, thermal underwear, gloves and shoes. Products with a ration of 65~200g/m2 have been used to make thermal clothing for soldiers in cold regions. (5) Oil-absorbing material Because PP fiber has good hydrophobicity and lipophilicity, low density (0.91g/cm3), low water absorption rate (0.01%), moisture regain of 0.05%, it is stable in oil insoluble and acid and alkali resistance. It is a very good oil absorbing material due to its chemical properties. The oil absorption of meltblown nonwovens produced from PP raw materials is 15~17 times of its own weight, and its water absorption is 0.71 to 1 times of its own weight. It has the characteristics of fast oil absorption, can float on the water surface for a long time after oil absorption, and can be reused. It is the most commonly used oil absorption material at present. (6) Wiping and industrial materials Meltblown cloth is also an excellent wiping material, which can be used for cleaning and wiping of precision instruments and equipment, and can also be used as a household wiping cloth. In order to prevent the fibers from falling off during use and affecting the use, a low temperature hot rolling process is often used to increase the surface strength of the meltblown cloth. Meltblown cloth is an excellent sound insulation and buffer material, which is widely used in the fields of construction and automobile manufacturing. Meltblown nonwovens are nonwovens manufactured by meltblown process, and also belong to products directly manufactured by melt spinning process.