The use of non-woven fabrics in the medical field can be traced back to World War II, when there was a demand for new and large quantities of medical products. In several published reports, non-woven fabric is considered the most effective bacterial barrier material. It was also found that they are superior to flax in reducing airborne pollution.
After significant development, non-woven materials can be designed to meet medical needs and are much better than similar woven products in terms of cost, effectiveness, and processability. Cross contamination has always been one of the biggest issues in hospitals, mainly due to the repeated use of woven robes, masks, and other similar items that can become contaminated and potentially spread bacteria. The emergence of non-woven fabrics has promoted the development of more cost-effective alternatives that are disposable and greatly reduce the problem of cross contamination.
Why choose non-woven fabrics for medical products?
Non woven fabrics are known for providing excellent performance in special tasks, as they can be designed according to the requirements of the application. The characteristics that make non-woven fabric the best choice for medical products are:
Excellent barrier performance
high efficiency
Better performance (comfort, thickness and weight, water vapor permeability, breathability, etc.)
Enhanced protection for users (better physical properties such as stretch resistance, tear resistance, wear resistance, etc.)
The possibility of cross contamination is relatively low
Wound care has been and is still the main use of medical and surgical non-woven fabrics. Non woven fabrics can find applications in various products. Absorbent pads, incontinence products, clothing for patients and staff. Baby diapers, bed sheets and blankets, burn dressings, nightgowns, disposable underwear, dressings, medication delivery devices, masks, filter media, nose patches, pillows, shoe covers, sponges, sutures, tissue scaffolds, towels, duvet covers, etc
These products can be effectively used in ambulances, beds, ICUs, laboratories, operating rooms, wards, and more.
Figure 1: Medical non-woven fabric
Materials used in medical non-woven fabrics:
Fiber type
The fibers used in medical non-woven fabrics can be divided into natural and synthetic categories. The natural fibers used are wood pulp, cotton, and synthetic silk. Wood pulp is used due to its obvious absorbency, large volume, and low cost. Cotton and synthetic silk are best used directly on wounds. They have good absorbency and can be made into high-quality non-woven fabrics.
The reasons for making high-quality medical non-woven fabrics from natural fibers are:
They highly absorb exudate and blood
Excellent breathability
Good aesthetic features
Easy to clean and can be disinfected
Excellent dimensional stability and high operating temperature up to 175 degrees Celsius
Biodegradable
Excellent drape and compliance
Good heat resistance
Excellent water retention capacity
Non allergic and non irritating fibers
The most commonly used synthetic fibers in this application are polypropylene, which has excellent rheological properties and requires hydrophobicity in some systems that require barrier properties. It is a low-cost, widely used two-component fiber for thermal bonding and increasing functionality, as well as high-strength polyester, where mechanical properties and ease of sterilization are crucial. Synthetic fibers also consider the strength, solvent resistance, electrostatic dissipation, and many other desirable properties of the product.
The characteristics of synthetic fibers required in many applications:
Hydrophobicity: Can be used as a barrier fabric
Easy to process
Cost effectiveness
High strength, low density, better performance
Easy to handle, no danger
Manufacturing process of medical non-woven fabric
Fiber web formation: The most popular techniques for medical non-woven fabrics are spunbond, meltblown, and their composite materials (SMS) for specific end uses. When a stronger fiber web is needed, spunbond can be used. The spunbond fiber web is strong in both the longitudinal (MD) and transverse (CD) directions. They are soft, porous, and dimensionally stable. Spunbond is commonly used in products such as face masks, headwear, shoe covers, bed sheets, and disposable clothing. Dry web forming, wet web forming, and combing are used for different fiber web characteristics, depending on the required fiber web thickness, the speed of the bonding technique to be used, etc. Sort out lightweight roll paper suitable for production in technology and hygiene products. Sort and produce high-quality nets at a high speed.
Adhesive bonding can be achieved through various methods, including thermal bonding of synthetic fibers and their mixtures. Water jet bonding is the fastest growing bonding technology and has been clearly used in medical non-woven fabrics. It has a texture and feel similar to textiles and is suitable for products such as gauze, dressings, hospital clothing, etc.
Acupuncture technique can be used to bond various medium thickness fibers or fiber webs. Acupuncture is a fast, effective, and commonly used technique for various applications. This is also cost-effective. In addition to all these techniques, stitching is also used. Chemical bonding is commonly used to manufacture elastic nonwoven fabrics.
Processing of natural fibers: For cotton and synthetic silk, it can be formed into a net through air flow/wet forming or combing. Natural fibers are typically subjected to hydraulic entanglement to impart most of their fabric like properties. Although the final product obtained has excellent performance, it is expensive compared to synthetic fibers. Cotton is usually treated with silk polishing and bleaching to improve its purity, thus gaining better acceptance in the medical and hygiene fields. Cotton also poses difficulties in processing due to its high dust content. Natural fibers find their best applications in surgical gowns, cotton swabs and curtains, gauze, disposable clothing, bandages, wound dressings, and other products. Cotton processing may involve bonding techniques such as resin bonding (for substrates), thermal bonding of polyolefin+cotton blends, and hydraulic entanglement for high absorbency products.
The process of synthetic fibers: Synthetic fibers are most commonly mixed with cotton/synthetic silk. Spin bond them and then bond them together using any suitable bonding technique. Synthetic fibers can also be melt blown. For applications such as filters, face masks, etc., meltblown fiber mesh is preferred because of its small fiber diameter and excellent filtration efficiency.
Although synthetic fibers can be effectively bonded through any technique, it mainly depends on their ultimate use.
Post processing
The post-processing of medical non-woven fabrics should provide suitable finishes for the specific end use of the product. The different types of finishing agents used in medical non-woven fabrics are:
Detergents: Used for bedding, nightgowns, and clothing for various purposes. It can also be used for curtains, blankets, etc.
Softener: Make the fiber mesh feel soft to the skin. Can be used for disposable underwear, pillows, bed sheets, etc.
Water repellent agent: used for children's bed sheets, isolation clothing, etc.
Flame retardant finish: used for bedding, curtains, clothing, lab coats, etc.
Antibacterial coating: very commonly used in gauze, dressings, and sutures. The most popular type is silver nanocrystals.
Resin and handmade additives: used for clothing, dresses, bed sheets, etc.
conclusion
Nowadays, the medical textile market has been completely saturated by non-woven fabric products. Non woven fabrics have become indispensable in this field due to their easy to modify properties and excellent performance. The healthcare and hygiene sectors together consume over 90% of the total non-woven fabric production in the United States (source: INDA). On the other hand, in developing countries in Asia, Africa, and South America, due to rapid urbanization, the demand for medical non-woven fabrics has significantly increased among young, health conscious populations. In the future, the demand for non-woven fabrics in the medical field is expected to steadily increase.
