Recently, the new crown pneumonia epidemic has spread all over the world, and masks have become a scarce material. The processing of protective masks is inseparable from the mask fabric, and the core of the mask fabric is the meltblown cloth.
Definition and use of meltblown cloth
Meltblown cloth is the core material of masks. Meltblown cloth mainly uses polypropylene as the main raw material, and the fiber diameter can reach 1 to 5 microns. The ultra-fine fibers with many voids, fluffy structure, good wrinkle resistance, and unique capillary structure can increase the number and surface area of fibers per unit area, so that the meltblown cloth has good filterability, shielding, heat insulation and oil absorption. . It can be used in air, liquid filter materials, isolation materials, absorbing materials, mask materials, thermal insulation materials, oil absorbing materials and wiping cloths and other fields. a lot of uses:
(1) Medical and sanitary cloths: surgical gowns, protective clothing, sterile wraps, masks, diapers, etc.;
(2) Cloths for home decoration: wall coverings, tablecloths, bed sheets, bedspreads, etc.;
(3) Clothing for clothing: lining, adhesive lining, flakes, shaped cotton, various synthetic leather base fabrics, etc.;
(4) Industrial cloth: filter material, insulating material, cement packaging bag, geotextile, covering cloth, etc.;
(5) Agricultural cloth: crop protection cloth, seedling raising cloth, irrigation cloth, thermal insulation curtain, etc.;
(6) Others: space cotton, thermal insulation and sound insulation materials, linoleum, cigarette filters, tea bags, etc.
The protective effect of meltblown cloth
At present, masks for virus protection are basically non-woven materials, and the mask fabric is composed of spunbond non-woven fabrics and melt-blown non-woven fabrics produced from polypropylene (PP) as raw materials. Medical masks are generally made of three layers of non-woven fabrics, as shown in Figure 1. The material is spunbond non-woven fabric + meltblown non-woven fabric + spunbond non-woven fabric, as shown in Figure 2, which is what we call the SMS (2 layers of S layer and 1 layer of M layer) structure. The high strength of (S), the small difference in vertical and horizontal strength, and the high shielding and waterproof performance of meltblown non-woven fabrics (M) are concentrated in one material, forming a material with strong waterproof performance, good air permeability and high efficiency.
(Figure 3)
The "S" and "M" layer materials are: S stands for Spunbond, and its fiber diameter is relatively thick, about 20 microns (μm), the outer layer S has the effect of blocking dust and water, which can prevent droplets from entering the mask, and the inner layer S has the effect of absorbing water and can absorb Moisture from the wearer's nose and mouth, 2 layers of S-spunbond support the entire non-woven structure. The blocking and filtering effect of SMS structure is shown in Figure 3.
The middle meltblown layer M (Meltblown) is the most important barrier layer. It is a very fine and electrostatic meltblown non-woven fabric with a fiber diameter of about 2 micrometers (μm). After the foam is close to the melt-blown non-woven fabric, it will be electrostatically adsorbed on the surface of the melt-blown non-woven fabric and cannot be penetrated. Since suspended particles such as dust are captured by the ultra-fine electrostatic fibers, it is extremely difficult to be detached by cleaning, and washing with water will destroy the electrostatic dust-absorbing ability, so this mask can only be used once.
