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At present, the world is actively preventing and controlling the epidemic. The most basic protective equipment for residents is masks. Since the virus requires high standards for masks, manufacturers must use meltblown nonwoven fabric in anti-virus masks. Let’s find out what is meltblown nonwoven fabric that is produced by non woven machine.

About meltblown nonwoven fabric

Meltblown nonwoven fabric is the core material of masks. Meltblown nonwoven fabric mainly uses polypropylene as the main raw material, and the fiber diameter can reach 1 to 5 microns. It has many voids, fluffy structure and good anti-wrinkle ability. And the ultra-fine fibers with unique capillary structure increase the number and surface area of fibers per unit area, so that the meltblown nonwoven fabric has good  performance of 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, wiping cloths,etc.

 

Structure of masks

The main structure of the medical mask is a three-layer nonwoven fabric, namely the SMS structure. The inner S layer is an ordinary nonwoven fabric, which is mainly used for moisture absorption. The outer S layer is a nonwoven fabric with waterproof treatment, which is mainly used to isolate the liquid sprayed by the patient and has the effect of preventing droplets. The middle M layer is an electret-treated meltblown nonwoven fabric, which can filter suspended bacteria and is the most important layer.

Meltblown nonwoven fabric, commonly known as the "heart" of the mask. Its main raw material is polypropylene, which is a film made of many crisscross fibers stacked in random directions. The fiber diameter ranges from 0.5 to 10 microns, and the fiber diameter is about one-third of the hair. Are you a little confused? With such a large gap in the meltblown nonwoven fabric, how does it filter viruses in the environment?

Taking the new coronavirus as an example, although the size of the new coronavirus is small, about 100 nanometers (0.1 microns), the virus cannot exist independently, and its transmission routes mainly include secretions and droplets when sneezing. The size is around 5 microns.

In addition, the meltblown nonwoven fabric is essentially a fiber filter. After the droplets containing the virus are close to the meltblown cloth, they will also be electrostatically adsorbed on the surface and cannot be penetrated.

Although the raw materials of the S and M layers of the mask are all polypropylene special resins, there are some differences in the production process between the special materials for meltblown nonwoven fabric and other nonwoven materials. Here are the main production processes below.

1. Petroleum → atmospheric and vacuum unit / secondary coking hydrogenated naphtha / hydrocracking light naphtha → ethylene cracker → ethylene / propylene → ethylene oxide / polypropylene (special resin)

2. S layer (spunbond layer): polypropylene special resin → sent to nonwoven fabric factory to produce S layer → sent to mask factory

3. M layer (meltblown layer): polypropylene special resin → sent to modified plastics factory to produce meltblown fabric special material → sent to meltblown nonwoven fabric factory to make M layer → sent to mask factory

Application of meltblown nonwoven fabric

(1) Medical and sanitary fabric: surgical gowns, protective clothing, disinfection wraps, masks, diapers, women's sanitary napkins, etc.

(2) Home decoration fabrics: wall coverings, tablecloths, bed sheets, bedspreads, etc.

(3) 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 felt, cigarette filters, tea bags in bags, etc.

Main specifications of meltblown nonwoven fabric

Weight: 18g-500g

Width: generally 160cm and 180cm (also according to customer needs)

Melt-blown cloth is to use high-speed hot air flow to draw the thin stream of polymer melt extruded from the spinneret hole of the die, thereby forming ultra-fine fibers and collecting them on the condensing screen curtain or drum, and at the same time bonding themselves to become Meltblown nonwovens.

The production process of meltblown nonwoven fabric is mainly as follows:

1. Melt preparation

2. Filter

3. Measurement

4. The melt is extruded from the spinneret hole

5. Melt trickle drafting and cooling

6. Network​​

How to identify the meltblown nonwoven fabric

It is easy for everyone to identify the inferior products of the two layers. A useful medical mask must have three layers, with spunbond nonwoven fabric on both sides, and a meltblown cloth of sufficient weight in the middle. The filtering effect is related to its gram weight (grams per square meter). This range is 18-500g, and the filtering effect of 40-50g or more is good. Don't buy a mask without a meltblown cloth! Identify real and fake meltblown nonwoven fabric masks by the following methods.

First, the meltblown layer will melt when encountering fire, but will not burn. Paper will burn when exposed to fire.

Second, the meltblown layer has static electricity. If you tear the meltblown layer into strips, you will obviously feel the electrostatic adsorption effect, and you can also adsorb strips of meltblown layers on the stainless steel. You can remove the used mask and check it to avoid wearing a fake mask.