At present, the cumulative number of confirmed cases of the new crown in the United States has exceeded 28.98 million, and there have been more than 524,000 deaths. Recently, the downward trend of the increasing number of confirmed cases in the United States seems to have stalled. In this regard, American infectious disease expert Fauci stated that it is "unacceptable." At the same time, some states have begun to relax epidemic prevention and control, which has also triggered a rebound of the epidemic.

Although the epidemic situation in the United States is still not optimistic, some states have begun to relax epidemic prevention and control measures. Recently, Connecticut, Arizona, West Virginia and other states have announced that they will lift passenger capacity restrictions on local restaurants, bars, gyms and other places; Alabama, Texas and Mississippi have also announced cancellations or plans to cancel.” Mask order".（Click to share to LinkedIn）

More than 100 people gathered outside the Capitol in Boise, the capital of Idaho, to hold a "mask burning" event to resist local orders for masks during the new crown epidemic.

In this regard, Warrensky, director of the US Centers for Disease Control and Prevention, said that the "mask order" should not be cancelled now; former Director of the US Food and Drug Administration Gottlieb also believes that in order to avoid a further rebound of the epidemic, the "mask order" is currently cancelled. "It's too early.

The base of confirmed cases of new coronary pneumonia is huge, and it is too early to take off the mask before the vaccine is popularized and confirmed to be effective. In the past year or two, masks are still the most cost-effective way to prevent epidemics. Masks are mainly composed of non-woven fabrics, so with the outbreak of the epidemic in 2020, the demand for non-woven fabrics will continue to increase.（Click to share to Facebook）

The non-woven fabric is made of polyester fiber, polyester fiber (abbreviated as: PET), made by needle punching process, and can be made with different thickness, feel, hardness, etc. Non-woven fabric has the characteristics of moisture-proof, breathable, flexible, light weight, flame retardant, non-toxic and tasteless, low price, recyclable and so on. Can be used in different industries, such as sound insulation, heat insulation, electric heating film, masks, clothing, medical, filling materials, etc.

What are the raw materials of non-woven fabrics?

Petroleum distillation and cracking can get propylene. Propylene is polymerized to get polypropylene. Polypropylene can be made into polypropylene fiber, which is what we usually call polypropylene. Polypropylene fiber (polypropylene) is the main fiber raw material for the production of non-woven fabrics, but it is not the only raw material. Polyester fiber (polyester), polyamide fiber (nylon), polyacrylonitrile fiber (acrylic), viscose fiber, etc. Can be used to produce non-woven fabrics.

Of course, in addition to the above chemical fibers, natural fibers such as cotton, linen, wool, and silk can also be used to produce non-woven fabrics. Some people often think of non-woven fabrics as chemical fiber products. This is actually a misunderstanding of non-woven fabrics. Like the clothing fabrics we usually wear, non-woven fabrics are also divided into chemical fiber non-woven fabrics and natural fiber non-woven fabrics, but chemical fiber non-woven fabrics are more common. For example, the cotton soft towel in the picture below is a non-woven fabric made of natural fiber-cotton.（try Suntech Meltblown machine）

How are non-woven fabrics made?

Let's first understand how the fiber comes from. Natural fibers exist in nature. Chemical fibers (including man-made fibers and synthetic fibers) are made by dissolving polymer compounds in a solvent into a spinning solution or high-temperature heating and melting into a melt, and then spin the solution or melt from the spinning solution. Extruded from the spinneret of the silk pump, the jetted stream cools and solidifies to form the nascent fiber, and the nascent fiber undergoes corresponding post-processing to form short fibers or filaments that can be used for spinning.

Raw material preparation-spinning solution/melt preparation-spinning forming-post-processing

（Suntech ST-ASS spunbond nonwoven machine）

Chemical fiber production process

Woven fabrics are made by spinning fibers into yarns, and then weaving or knitting the yarns into fabrics. Non-woven fabric does not require spinning and weaving, so how does it turn fibers into cloth? There are many production processes for non-woven fabrics, and the processes are also different, but the core processes all include fiber web formation and fiber web reinforcement.

Fiber web

"Fiber Laying", as the name implies, is to make fibers into a net. Common methods include dry-laid, wet-laid, spun-laid, melt-blown, and so on.

Dry-laid and wet-laid webs are more suitable for short fiber webs. Generally, it is necessary to pre-process the fiber raw materials, such as tearing large fiber clusters and fiber blocks into small pieces to loosen them and remove impurities from them. , Mix the various fiber components evenly, and make preparations before forming a net. The dry method generally involves combing and laying pre-processed fibers into a fiber web with a certain thickness. Wet-laid is to disperse short fibers in water containing chemical additives to form a suspension slurry, and then filter the water, and the fibers deposited on the filter will form a fiber web.

Spinning into a net (top) and meltblown into a net (bottom)

Both spinning and meltblown webs are spinning methods using chemical fibers, and the fibers are directly laid into a web during the spinning and forming process. Among them, the spinning solution or melt is sprayed from the spinneret to form filaments of a certain fineness after cooling and stretching, and forming a fiber web on the receiving device. The melt-blown web uses high-speed hot air to extremely stretch the fine stream ejected from the spinneret to form ultra-fine fibers, which are then gathered on the receiving device to form a fiber web. The diameter of the fibers formed by the melt blown method is smaller, which is beneficial to improve the filtration efficiency.

Fiber mesh reinforcement

The fiber webs made by different methods have loose connections of internal fibers and low strength, which is difficult to meet the needs of use, so it needs to be reinforced. The commonly used reinforcement methods include chemical bonding, thermal bonding, and mechanical reinforcement.

Chemical bonding reinforcement method: the bonding agent is applied to the fiber web by dipping, spraying, printing, etc., and then heat treatment is performed to evaporate the water and the bonding agent to solidify, thereby strengthening the fiber web to form a cloth.

Thermal bonding reinforcement method: Most high molecular polymers are thermoplastic, that is, they will melt and become sticky when heated to a certain temperature, and then resolidify after cooling. This principle can also be used to reinforce the fiber web. Commonly used are hot air bonding-using hot air to heat the fiber web to make it bonded and reinforced; hot rolling bonding-using a pair of heated steel rollers to heat the fiber web and apply a certain pressure to make the fiber web bonded and reinforced.

What are the uses of non-woven fabrics?

Compared with other textile fabrics, non-woven fabrics have short process flow, fast production rate, high output, and low cost. Therefore, non-woven fabrics are widely used, and their products can be seen everywhere, which can be said to be closely related to our daily lives.

Many disposable sanitary products used in our daily life use non-woven fabrics, such as disposable bed sheets, quilt covers, pillowcases, disposable sleeping bags, disposable underwear, compressed towels, facial mask paper, wet wipes, cotton soft towels, sanitary napkins, and diapers Wait. Non-woven fabrics are also inseparable from surgical gowns, isolation gowns, masks, bandages, dressings, and wrapping materials in the medical industry. In addition, wall coverings, carpets, storage boxes, vacuum cleaner filter bags, heat insulation pads, shopping bags, clothing dust covers, etc. used at home, floor mats in cars, roof cloths, door linings, filter cloths for filters , Activated carbon packaging, seat covers, sound insulation and shock-absorbing felt, rear window sills, etc. are also widely used non-woven fabrics.

With 50 years of technical precipitation and design experience, Suntech has developed and produced intelligent non-woven fabric machines, including melt blown machines, spunbonded non-woven machines, spun-melt non-woven machines, non-woven bag machines, and assisted the production of masks and other textile products. Contribute to the cause of human health and environmental protection.