I. WHAT IS NONWOVENS?
Nonwovens – a term is used in the textile industry to show fabrics are created not exclusion woven by shuttle or knitwoven methods. Nonwovens are like those are made from short fibers and long (long continuous) fibers, which are linked together by chemical, mechanical, thermal or solvent treatment.
Nonwovens is defined by production technology as sheet structures or networks linked together by fibers or filament by mechanics needle tattoo (needle tattoo manufacturing technology), extrusion blows molten plastic (PP spunbond – meltblown nonwoven) or chemical. They are flat or rough foam sheets are made from separate fibers directly , molten plastics or plastic films. They are not created by weaving or knitting and are not required fibers conversion into fabrics.
Usually, the recycled fabrics with a certain proportion and oil-based materials are used in nonwovens. The proportion of recycled fabric varies that is based on the strength of the material is required for specific use. In addition, some nonwovens can be recycled after use, are properly and comfortably treated. For this reason, some of people see nonwovens as a more ecological fabric for certain applications. Especially, in the sectors and the industries where single-use products are important, such as hospitals, schools, old-age pensioners institute and luxury accommodations.
Nonwovens is a fabric is designed to be usable once, with limited or very durable life. Nonwovens is provided specific functions such as absorbentness, liquid waterproofing, elasticity, tension, softness, durability, fire resistance, washing, cushioning, insulation, sound insulation, filtration ability. It is used as a bacterial and sterile barrier.
These properties are often combined to create fabrics suitable for specific jobs, simultaneous to reach a good balance between product time and cost. The people can produce nonwovens to look like the textile’s form,tructuring and durability.
These properties are often combined to create fabrics suitable for specific jobs, while achieving a good balance between product time and cost. They can mimic the shape, texture and durability of woven fabrics. It can be bulky as the thickest pads. It is combined with other materials to create some of products with multiform proprety, and be used alone or as components of garments, home furniture, healthcare, engineering, industry and consumer goods.
II. NONWOVENS GENERAL INTRODUCTION:
Nonwovens can be divided into 8 types according to different production processes
1. Spunlace Nonwovens
This is a product is created from the direct use of polymeric resins, short fibres or filaments to form a fiber network thanks to the action gas or mechanic, stretch process, needle piercing or hot rolling, and the final section after finishing is the spunlace nonwovens product.
2. Thermally Linked Nonwovens
This type of nonwovens is mainly produced by several processes: adding fibre form or adhering to the fibre network sub-material, and then network reinforcing into the fabric through heat input and cooling process
3. Pulp airlaid nonwovens
Pulp airlaid nonwovens is also known as dust-free paper, dry nonwovens. They are used air-laid technology to open the wooden fibre board into a single fiber state, then uses the gas flow method to agglomerate the fibres on the more reinforced mesh film and the fibroreticulateto to form the cloth
4. Wet nonwovens
Wet nonwovens is produced according to the following process: fibers from lead wool are spread and stacked in each layer, then they are tightly pressed through each station under high water pressure.
5. Needle tattoo nonwovens
Needle tattoo nonwovens is produced according to the following process: fibers from lead wool are spread and stacked in each layer. Then, then are hot rolled. Finally, they are tight pressed with continuous needle tattoos through each station to create nonwovens according to the desired thickness.
6. Nonwovens stitch
Sewing nonwovens is another type of dry nonwovens. The manufacturing process is used vertical knitwear fiber ring structure to reinforce yarn net and layer, the nonwoven materials (such as plastic sheets, plastic foil, etc.) or their combination to form nonwovens.
7. Spunbond Nonwovens
Spunbond nonwovens is produced by melted PP plastic fibers extruding through a flat mold contains thousands of small holes to form long thin fibers then are cooled by cold air blowing into them, while they are stretched as they fall from the flat mold to the conveyor. Each of silk thread is then processed into nonwovens thanks to the adhesive method, thermal and mechanical bonding.
8. Meltblown Nonwovens
Melblown nonwovens is produced by melted PP plastic fibers extruding through a flat mold contains thousands of small holes to form long thin fibers then are cooled by hot air blowing into them, while they are stretched as they fall from the flat mold to the conveyor. Each of silk thread is then processed into nonwovens thanks to the adhesive method, thermal and mechanical bonding. Normolly, this nonwovens is added to spunbond fibers to form SMS, SMMS or SSMMS fabrics.
III. WHAT IS PP NONWOVENS:
PP nonwovens is also known as SPP or SMS, SMMS, SSMMS nonwovens are made from oriented or accidental fibers, manufactured according to spunbond-meltblown nonwovens technology. This is a new environmental friendly material generation. It can moisture resistant, opening air, plasticity, lightweight, non-flammable, biodegradation, non-toxic and non-irritated, color and price variety. Low cost, recyclable.
Polypropylene pellets (pp material) are used as the main raw material, which is produced by melting, yarn stretching, hot-rolling at high temperatures and high speed producing. It is called to be cloth because of external appearance and some of fabric’s properties.
Depending on the use purpose, there are many types of PP nonwovens with different structures such as S, SS, SMS, SMMS, SSMMS
In nonwovens – signs S, SS, SMS, SMMS means:
S: Spunbonded nonwovens = S one-layer nonwovens
SS: Spunbonded + Spunbonded = S two-layer nonwovens
SMS: Spunbonded + Meltblown + Spunbonded = M one-layer in the middle and outside S two-layer nonwovens.
SMMS: Spunbonded + Meltblown + Meltblown + Spunbonded = M two-layer in the middle and outside S two-layer nonwovens.
Rang Dong Healthcare Plastic Joint Stock Company has invested in a SMMS four-layer PP nonwovens production line and can be upgraded to SSMMS five-layers, the 3.2m first size in Vietnam with European modern producing technology. Product is met American standards such as AAMI from level 1 to 4 applied to products medical protective clothes, surgical chancre … and achieved Bacterial Filtration Efficiency BFE> 98% to meet in the U.S. standards for ASTM F2100-19 and EN14683:2019 European medical masks
The width of the product varied from 100mm to 3200mm which can meet most of the requirements of the medical PP nonwovens market
2. PP nonwovens categories and supplied standards to the market: