一. Spunlaced Nonwovens
 
Spunlace technology is to spray high-pressure micro water into one or more layers of fiber nets, so that the fibers intertwine with each other, so that the fiber nets can be strengthened and have a certain strength.
 
Features: flexible tangle, does not affect the original characteristics of the fiber, does not damage the fiber. The appearance is closer to the traditional textile. High strength and low fuzziness. High moisture absorption, fast moisture absorption. Soft hand, good drapability. The appearance is changeable. Long production process and large floor area. Complex equipment, large energy consumption, high water quality requirements.
 
Main applications: Medical curtain, surgical suit, surgical cover cloth, medical binding material, wound dressing, medical gauze, aviation rag, clothing lining base cloth, coating base cloth, electronic industry advanced rag, cosmetic cotton, wet towel, mask covering material, etc.
 
二.Spunbond nonwovens
 
Spunbond nonwovens are made of continuous filaments after the polymer has been extruded and stretched. The filaments are laid into a net, and then the net is made into a nonwovens through self adhesion, thermal adhesion, chemical adhesion or mechanical reinforcement.
 
Features: the fabric consists of continuous filament. Excellent tensile strength. There are many technological changes, so many methods can be used for reinforcement. The change range of filament size is wide.
 
Application: polypropylene (PP): geotextile, tufted carpet base cloth, coating bottom cloth, medical and health materials, covering materials for disposable products, etc. Polyester (PET): filter material, lining material, tufted carpet base cloth, agricultural material, packaging material, etc.
 
 
三. Melt blown nonwovens
 
The technological process of melt blown non-woven fabric: polymer feeding - melt extrusion - fiber formation - fiber cooling - mesh formation - reinforcement into fabric. High speed hot air is used to draft the polymer melt thin flow extruded from the spinneret hole of die head, so as to form superfine fiber and agglomerate it on the condensing net curtain or roller, and to form nonwovens by self adhesion. Features: the fiber net is composed of very fine short fibers. It has good uniformity and soft hand. The filtration performance and liquid absorption performance are good. The web strength is poor.
 
Application: filter materials, medical and health materials, clothing materials, battery diaphragm materials, wiping materials.
 
四. Thermosetting nonwovens
 
The fiber mesh is added with fiber or powder hot-melt bonding reinforcement material, and then the fiber mesh is heated, melted and cooled to form a cloth.
 
Features: surface bonding hot rolling surface more smooth, point bonding hot rolling relative fluffy.
 
Application: production of baby diapers and women's sanitary napkin covering materials, ointment base cloth, clothing lining, masks, etc.
 
Non-woven fabric made of pulp by air flow
 
The air formed nonwovens can also be called dust-free paper and dry process paper-making nonwovens. It uses the air flow to form a net to loosen the wood pulp fiberboard into a single fiber state, and then uses the air flow method to make the fiber agglutinate on the net forming curtain, and then the fiber net is reinforced into a cloth.
 
Features: good fluffy, soft hand, super moisture absorption.
 
Application: medical sanitary materials, especially disposable sanitary products with high water absorption (such as diapers, sanitary napkins, wet facial napkins, wipes, etc.).
 
五. Wet Nonwovens
 
Wet non-woven fabric is to loosen the fiber materials in the water medium into a single fiber, at the same time, mix different fiber materials to make fiber suspension slurry, the suspension slurry is delivered to the mesh forming mechanism, and the fiber is formed into a mesh in the wet state and then reinforced into a cloth.
 
Features: high production speed, up to 400m / min. It can make full use of short fiber. The fiber uniformity of the product is good. Large water consumption, high one-time investment.
 
Application: special paper: dust / liquid filter paper, tea bag. Industrial use: filter, insulating material, sound-absorbing material. Medical use: Medical backing, medical tape, surgical wrapping material. Civil use: wallpaper, etc.

六. Needled Nonwovens
 
Needled non-woven fabric is a kind of dry non-woven fabric. Needled non-woven fabric uses the puncture effect of the needle to strengthen the fluffy fiber net into cloth.
 
Features: flexible tangle between fibers, with good dimensional stability and elasticity. Good permeability and filtration performance. Feel plump and fluffy. According to the requirements of the production of a variety of set patterns or three-dimensional products.
 
Application: geotextile, geomembrane, halberd flannelette, speaker blanket, electric blanket cotton, embroidery cotton, clothing cotton, Christmas crafts, human leather base cloth, filter material special cloth.
 
七. Sewn non-woven fabric
 
Sewing non-woven fabric is a kind of dry non-woven fabric. It uses warp knitting coil structure to reinforce fiber net, yarn layer, non-woven material (such as plastic sheet, plastic thin metal foil, etc.) or their combination to make non-woven fabric.
 
Features: durability, disposable. Insulation, conductive. Soft, rigid. Fine density, expansibility.
 
Application: clothing lining, flocs, toe hard lining, heel lining, underwear, artificial deerskin, synthetic leather, warm shoe lining, cloth sole lining, etc
 
八. Hydrophilic Nonwovens
 
It is mainly used in the production of medical and health materials, so as to achieve better hand feel and non scratch skin. Such as sanitary napkin, sanitary gasket is to use the hydrophilic function of hydrophilic non-woven fabric.
 
Features: non-woven fabric has a certain ability to absorb water.
 
Application: medical supplies, health care supplies, sanitary napkins, sanitary pads, etc.
 
Of course, due to the lack of clear standards, this paper summarizes the previous experience in the detection of respirators and non-woven fabrics, and puts forward several important detection indicators, namely, filtration efficiency, respiratory resistance, health indicators, toxicology tests.

1、 Filtration efficiency
 
As we all know, filtration efficiency is the key index of mask quality evaluation. This is also one of the important quality standards of non-woven fabrics, so with reference to relevant standards, we recommend that the bacterial filtration efficiency of non-woven fabrics of masks should not be less than 95%, while the particle filtration efficiency for non oily particles should not be less than 30%.
 
2、 Respiratory resistance
 
Respiratory resistance, for people wearing masks, the size of the impact of respiratory obstruction. Therefore, the non-woven respiratory resistance of the mask determines the respiratory comfort when wearing the mask. Here we recommend that the inspiratory resistance should be ≤ 350pa, and the expiratory resistance should be ≤ 250pa.
 
3、 Health indicators
 
Health index is another important index of non-woven fabric. In this paper, we recommend that the detection items mainly include initial pollution bacteria, total bacterial colonies, coliform bacteria, pathogenic suppurative bacteria, total fungal colonies, coliform bacteria, Staphylococcus aureus, Candida albicans, ethylene oxide residues, etc.
 
4、 Toxicology test
 
Skin irritation test is mainly a protective test for people who are allergic to some materials. Refer to GB 15979. The non-woven skin irritation test of respirator is mainly to cut the sample of appropriate area in a cross-section way, apply it to the skin after being soaked with normal saline, and then cover it with spot sticker for test.
 
Siyuan medical equipment warm reminder: in addition to providing effective protection, wearing masks must also take into account the comfort of the wearer, not to bring biological hazards and other negative effects. Generally speaking, the higher the protective performance of the mask, the greater the impact on the comfort performance. When people wear masks to inhale, they have a certain resistance to air flow. When inspiratory resistance is too large, some people will feel dizzy, chest tightness and other discomfort.
 
Different people have different industries and physiques, so they have different requirements for the sealing, protection, comfort, adaptability and other indicators of masks. Some special groups, such as children, the elderly, people with respiratory system diseases and cardiovascular diseases, should carefully select the type of mask, and avoid the occurrence of anoxia and dizziness and other accidents for a long time under the premise of ensuring safety protection.