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This eBook provides helpful information for both nonwoven fabric

mills and manufacturers of nonwoven medical apparel and products.

The information is intended to aid the selection of a moisture resistant

grades that will be most effective for each unique product.

Medical Moisture-Resistant Nonwovens

The Advantages of Moisture Repelling Nonwovens 5

A Wide Variety of Medical Applications 6

AAMI Rating for Protective Apparel and Drapes 8

Fluoropolymer-based vs. Silicone-based Repellents 10

The Challenges of Selecting the Best Repellents for Nonwovens 14

The Importance of Reliable Performance Evaluations 16

Primer of Testing Options for Nonwovens 18

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The Advantages of Moisture Repelling Nonwovens

With today’s increasing number of hospital-acquired infections,

medical facilities are always looking for better ways to protect their

patients and staff. Nonwoven garments and products help provide

this protection.

When medical garments like gowns, drapes, bibs and masks are made

of repellent nonwoven fabrics, they provide a barrier of protection

from fluids that can carry infections.

In addition, disposable medical products like dressing, bandages,

tapes, bibs and pads must be able to repel fluids, oils, and alcohols.

These products play an important role in emergency response,

the operating room and many other healthcare environments.

To effectively guard against fluids, medical disposables are fabricated

from nonwoven fabrics that were coated with repelling agents as

rolled goods.

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A Wide Variety of Medical Applications

Nonwovens are extensively used in the medical field. When coated with

repellents, nonwovens offer protection from the patient’s blood and

bodily fluids which prevents the spread of infections, diseases and cross-

contamination in medical and surgical environments.

The spread of infections and diseases is further hindered because fresh,

sterile garments and products are so readily available. Handling is minimized

and nonwoven products are inexpensive enough to be incinerated after each

use. They typically offer a higher level of quality and consistency versus

reusable products.

Because of these advantages, single use nonwoven materials are used for

dozens of healthcare products. Over 90% of healthcare facilities use

nonwoven drapes and over 85% use nonwoven gowns. Although

these synthetic materials may be hydrophobic, they still require chemical

coatings to improve their level of repellency.

• Surgical caps, gowns, masks,

and shoe covers (single-use)

• Orthopedic padding

• Bandages

• Drapes, wraps, packs

• Packaging

• Bed linen

Medical Applications

Benefits of Repellent Nonwoven Fabrics for Medical Products

• Surgical apparel repels blood and

other bodily fluids during emergency

medical and surgical procedures

• Coated bandages keep healing

wounds dry

• Bedding and drapes stay dry despite

constant contact with bodily fluids,

oils, and alcohols

• Patients, doctors, and responders

remain comfortable and protected

• Medical environment remains sterile

Many of the products are used only

once and then incinerated, and so

the growth and transfer of bacteria,

disease, and infection are inhibited.

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AAMI Ratings for Protective Apparel and Drapes

As discussed previously, the healthcare industry depends on the

effectiveness of moisture barrier materials to protect people from toxins,

infection, and disease. Healthcare workers must choose products made

from nonwoven fabrics that offer the appropriate level of protection.

There is a standard that can be followed which classifies barrier

effectiveness, and covers all surgical gowns and other protective apparel,

as well as drapes and drape accessories. In 2004, the FDA recognized the

consensus standard American National Standards Institute/Association

of the Advancement of Medical Instrumentation (ANSI/AAMI)

PB70:2003 that describes liquid barrier performance and classification of

protective apparel and drapes intended for use in healthcare facilities.

The AAMI standard requires manufacturers to label

their fabrics based on the level of fluid repellency

they provide. It also specifies the test methods

and performance results necessary to verify and

validate the defined levels of protection.

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Fluoropolymer-based vs. Silicone-based Repellents

Silicone repellents can also be used on nonwoven fabrics. They usually

consist of polydimethylsiloxanes, and are sometimes functionalized

with alkyl groups to increase their water repellency.

Like fluoropolymer-based repellents, silicon-based repellents have low

surface energy. Since the surface energy of the fabrics on which they

are applied is lower than the surface tension of water, fluids like blood

can’t get into the fabric fibers. Silicone repellents effectively repel water,

but they offer little to no oil and solvent repellency. Also, they do not

have good stain release qualities and they lack durability unless reactive

functional groups are incorporated.

Fluorochemicals have even lower surface energy than silicones, so they

have superior repellency with water, oil and solvents. Also, the carbon

fluorine bond is more stable, which increases the performance and

durability of fluoropolymer-based coatings.

SILICONE REPELLENTS

FLUOROCHEMICAL REPELLENTS

Surface energy Low Very low

Cost Lower Higher

Water repellency Good Very good

Oil/solvent repellency Poor Good

Durability Poor Good

Loading requirement High Low

Silicone coatings used to be preferred by manufacturers because

they were more environmentally friendly, and they are still considered

the more eco-friendly option. However, today’s fluorochemicals

use C6 technology and no longer contain PFOAs, so they are also

environmentally friendly.

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AAMI Standards of Protection

Level 1: Minimal Risk To be used, for example, during basic care, standard

isolation, cover gown for visitors, or in a standard

medical unit

Level 2: Low Risk To be used, for example, during blood draw, suturing,

in the Intensive Care Unit (ICU), or in a pathology lab

Level 3: Moderate Risk To be used, for example, during arterial blood draw,

inserting an intravenous (IV) line, in the Emergency

Room, or for trauma cases

Level 4: High Risk

To be used, for example, during long, fluid-intense

procedures, surgery, when pathogen resistance is

needed, or when infectious diseases are suspected

(non-airborne)

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The Challenges of Selecting the Best Repellents for Nonwovens

Most manufacturers specify repellent coatings for their disposable

nonwoven products so they can repel liquids, release stains easier, or

both. However, selecting the best fluorochemical grade is challenging

because repellency and stain release are competing properties.

Fluorochemicals aid stain release by coating the fibers of the fabric so

the stain can’t hold onto the fibers. But this strong water repellency

becomes an issue when trying to remove stains that are already set in

the fabric fibers.

To remove a stain, water and detergent must be able to enter the fabric

to surround the stain. Highly water repellent surfaces prevent this from

happening.

To resolve this problem, formulators incorporate monomers with

hydrophilic characteristics into the fluoropolymer, but this lowers

dynamic water repellency.

Stain release isn’t as much of

an issue in the medical industry

because most nonwoven products

are single-use, but applications

requiring stain release require

performance testing to select

the best grade.

Repellent chemical suppliers like AGC work hand in hand with

manufacturers and mills to figure out which grade is best for their specific

application. For example, we set up the fabric treatment process in the

lab so we can treat fabrics using the same conditions as our customers.

We typically use a size press equipped with roller pressure and speed

adjustments.

We also dry fabrics the same way as the mills, using a tentor drying

oven with two-stage temperature controls and adjustable dwell time.

Reproducing their processes with their fabric samples lets us recommend

the optimal treatment conditions, which takes the guesswork out the

manufacturing process.

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The Importance of Reliable Performance Evaluations

It is important to remember that the reliability of performance evaluations

is just as important as the result of those evaluations. That’s why our lab

gets as much information about customers’ recipes as possible, including

reagents, quantities, order of addition, temperatures, wet pickup, etc.

We also look at several other factors to assess the overall finishing process

such as run rates, foaming problems, pad-bath stability, and polymer

build-up on fabric. This allows us to identify pitfalls and communicate

important process information to our customers before problems

occur. It’s the best way to avoid unexpected problems during commercial

production.

For example, consider foaming issues. Foaming is rarely a problem during

testing because the fabrics are run slowly and methodically. But things

might be dramatically different in actual use when the mills run fabrics

through as fast as possible. If the formulations are evaluated ahead of time

for foam production, the mill would know if the formula will foam and

become a problem with fast run rates.

Knowing things like the likelihood of a formulation to produce foam, the

amount of foam, the stability of the foam, and the impact of the foam on

production helps mills determine whether or not foaming will affect their

production, which prevents unexpected production shut-downs.

AGC’s lab uses industry standard test methods and

data validation so we can provide customers with

reliable product recommendations.

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Primer of Testing Options for Nonwovens

Numerous tests can be conducted to help mills and manufacturers select

the best repellent product for each nonwoven project. Coatings can affect

product quality and performance, so understanding the latest technologies

available is well worth the effort.

Knowing your options requires due diligence. Many mills have established

relationships with one repellent supplier and are not aware of the latest

technologies, techniques and testing services that can improve their

product quality.

Leading repellent suppliers like AGC Chemicals Americas have the

laboratory resources and specialists to conduct these tests for

customers. For example, at AGC’s testing lab, nonwoven fabric mills can

test their specific fabrics with varying grades of AsahiGuard repellents.

Performance testing for nonwoven fabrics includes

testing for water/oil repellency, hydrostatic pressure,

surface resistivity, static decay, and stain release.

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Water/Oil Repellency Test

Measures how well the fabric repels water and oil. Three drops of the

IPA/Water solutions or test oils are placed on the nonwoven fabric. The

fabric passes the test if no wetting is observed after 5 minutes. As you go

up the test scale, the surface tension of these water and oil tests decrease.

The lower the surface tension of the liquid applied, the lower the surface

energy of the coating must be to repel it.

Hydrostatic Pressure Test

Measures the force (kPa, cm of water, or inches of water) and time

required to force a liquid, usually water, through a piece of nonwoven

fabric. The larger the force and time required to penetrate the fabric,

the more resistant the fabric is to that particular liquid.

Surface Resistivity Test

Measures how much static charge can be applied to a fabric by measuring

the electrical resistance of the fabric surface between two concentric rings.

Knowing how much charge can build up on the surface of the fabric is

important when the nonwoven product will be used in the healthcare

environment around sensitive medical devices and equipment.

Static Decay Test

Measures the time it takes for a charge applied to a fabric to dissipate.

Again, this charge can affect medical devices.

Stain Release Test

Measures ability of fabric to release oily stains during laundering. Corn

oil and mineral oil is applied to fabric for 60 seconds before washing.

Today’s medical disposables must perform better than ever to protect

staff and patients from fluids that spread infections and disease. By

understanding the latest repellent technologies and taking a collaborative

approach with the supplier, nonwoven fabric mills and manufacturers can

be sure they are selecting the best grade for each product.

For more information on repellents for medical nonwovens, visit www.agcchem.com or call 800.424.7833.

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About AGC & AsahiGuard Recognized by the industry for its advanced fluorine chemistry technologies,

AGC Chemicals Americas developed AsahiGuard AG-E600, a high-performance,

PFOA-free repellent with improved environmental and biological profiles.

AsahiGuard has proven safe and effective for use in nonwoven medical textiles,

and poses no danger to humans, animals, materials, or the environment. It also

meets the most stringent international regulatory requirements. In fact, AsahiGuard

is commonly used at the cutting edge of healthcare, due to its resistance to alcohol,

water, and other fluids encountered in the healthcare industry. AGC maintains a

corporate vision to “Look Beyond,” and so anticipates new global requirements

and creates value for its customers by continuously innovating technologies and

improving customer service.

AGC Chemicals Americas, Inc.55 E. Uwchlan Avenue, Suite 201Exton, PA 19341USA

www.agcchem.com