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Highloft nonwovens in the 1990's.

or, How to Ask for a Mouse and Not Receive a Dwarf Elephant

Textile or fibrous materials play a major role in our lives everyday. I have calculated that if a person lived to be 100 years old, there would only be a few hours when he or she is not touching a textile. It isn't just the clothes we wear but there is the washcloth in the bath, the carpet we stand on, the furniture we sit on, the bedding we sleep on, the bandage on our wound and hundreds of other products that contain fiber. When it's time to depart, we will probably be resting in a casket containing several different textile materials.

People are not only in physical contact with a fibrous or fabric-like structure most of their lives, but these structures are around us performing functions that improve our lives and provide desirable qualities. Some are seen, such as attractive wall coverings, while others are not seen, such as the insulation in our buildings. When we put them all together they spell billions of pounds, yards and/or dollars each year worldwide. Nonwovens are taking a larger portion of many of these markets each year and this trend will no doubt continue.

Everyone that is familiar with nonwovens should be convinced that these processes and the products that can be manufactured from them have proven themselves, particularly over the past 30 years. Indeed, they have become the most competitive force in textile-like end use markets. There are many categories our industry uses to describe products, properties and end use requirements. After all, communication will probably always be a problem when we attempt to get a supplier or converter to deliver what we want or need for a given use because of the numerous properties and characteristics involved in a textile-like fabric.

Typically we may request a fibrous sheet or fabric that is a given weight, width, thickness, color, softness and with certain chemical additives. The nonwoven manufacturer gets a picture of an elephant from the description you have given him of the mouse you really wanted. After receiving his sample, you begin to offer additional details of your requirements such as it should absorb chicken fat, be soft when frozen and biodegrade in moonlight during the 22nd century. After this conversation, you receive a second sample of a dwarf elephant with mud flaps and a rearview mirror. Close but no prize.

Two observations emerge from this situation. One is that you have not communicated your product's needs. Maybe you are fishing and want to know if the nonwoven manufacturer will supply something better than what you had in mind. Maybe you don't know the extent of what properties can be engineered in such a fabric. The second is that the nonwoven manufacturer can be in the same leaky boat. He does not know what you want and he may also be aware of what properties he can deliver with his existing processes.

A third observation or problem has existed in the textile industry since it began and now continues in the nonwovens industry. What does the buyer or user mean when he or she says soft, attractive, desirable or pleasing to the customer? How does durable or disposable translate into the physical and chemical properties of a nonwoven fabric? Now that I have filled the air with questions without answers and problems without solutions, I will continue in that vein by relating these to highloft nonwovens.

Tracking The Highloft Elephant

For the past few years many of us have been trying to get the industry to define highloft nonwovens as a category because it has its place and properties that are often different from other nonwovens. In addition, by our definition, it is the largest category. The definition we proposed in 1991 was:

"Highloft nonwovens are a low density fiber network structure characterized by a high ratio of thickness to weight per unit area. The fibers can be continuous or discontinuous, bonded or unbonded. Highloft battings have no more than 10% solids, by volume, and are greater than three millimeters (0.13 inch) in thickness."

This definition by no means describes all the properties or parameters of what a highloft nonwoven could possess. It does however offer a description to assist in communicating, segregating and/or understanding a given portion of the seemingly incomprehensible nonwoven marketplace. INDA, Association of the Nonwoven Fabrics Industry, has been assisting those interested in not only defining highloft but also in test procedures. These efforts should eventually result in better standards as well as agreement on definitions.

One of the major characteristics of highloft nonwovens is the voids or spaces within the fibrous structure. These voids can provide trapped air to insulate, a reservoir for fluids, an entangled path with great surface areas, bulk to fill or stabilize, softness with durability, sound absorbing, wicking and containment as well as many other properties. Therefore we find that filtration is a large market for such products where the voids and surface area attract unwanted materials. Roofing products fill the voids with bitumen and pultrusion fills them with different polymers depending on the end product needs.

Highloft nonwovens have been around for a few thousand years in pillows, quilts, bedding and other end uses where cotton, wool, jute and other natural hair and fibers were available. These were processed by hand. Around the turn of the century cotton and wool continued to be the major fibers and they began to be processed on garnetts/cards in larger volumes.

In the 1950's and 1960's, companies producing cotton batting began using rayon and acetate in their highloft battings. These products were used in "filling" and insulation, primarily in bedcoverings, pillows, automotive and other insulation and padding products. The term batting was used for most of these products and they were typically not bonded. Often these batts were covered with a lightweight woven fabric on each side.

These fibers gave a new perspective to highloft. For the first time products could be made that were non-allergenic, pure white, resisted shrinkage, offered predictable processing, continuity of quality and more because of the new manmade uniform fibers.

During the 1960's polyester fibers were designed for filling applications where crimp, fiber cross-sections and finishes were engineered to enhance the processing and end use properties of fiberfill products. Spray bonding of battings with acrylic binders was developed and spray bonded polyester became the dominant fiberfill product. The acrylic binder bonded the fibers at their crossover points, thereby preventing their entangling and assisting in maintaining their loft even during washing. During this period the term "fiberfill" became the dominant label for polyester highloft nonwovens or battings.

The typical polyester "fiberfill" highloft line evolved from the 1960's through the 1980's and contained the following equipment and process steps: 1. opening; 2. blending; 3. opener/feeder; 4. web maker (card/garnett/airlay); 5. crosslapper; 6. spray (chemical binder); 7. oven (drying/curing); 8. slitter/edge trim; 9. wind up; 10. packaging; 11. shredder for reclaim.

Polyester not only offered unique properties to the fiberfill applications such as improved compression resistance, resistance to fluids and washability, but it offered properties for many other markets. These included filtration, geotextiles, agriculture, interlinings, thermal insulation, cleaning products as well as healthcare and many other end uses.

By selecting various fibers and combining their attributes, one can engineer many different products with a variety of properties. A large denier polyester may be used for its compression resistance or stiffness and be combined with an acrylic for wicking abilities. Superabsorbent fibers may be added to contain and hold liquids. Metal or other fibers may be added to conduct electricity or prevent transmission of various frequencies.

Nearly every fiber has been used in some highloft product. Fibers made from steel to exotic plants have been successful in a variety of end uses from auto mufflers to wound dressings. Most highloft nonwovens are made with "staple" fiber. This is fiber that has been extruded into filaments, crimped and cut to lengths from about one half to three inches. However, the fibers may also be extruded in nonwoven processes such as glass insulation, melt blowing and spunbonding. The melt blown and spunbonded processes begin with polymers that are transformed into filaments that are collected into webs in a single operation.

Staple fibers of different characteristics can be added to these processes either during or after extrusion. As an example, melt blown typically produces polypropylene micro fibers (one half denier), which offer many advantages such as surface area per weight. However, they are more likely to collapse or compact in products such as sorbents and insulation, which are large markets for melt blown. By the addition of larger polyester fibers (such as six denier or larger), the highloft can resist compression along with offering greater strength and other advantages. Pulp and other materials can also be added during extrusion in melt blowns and spunbonds to achieve the properties for a given market.

Binder fibers have played a major role in highloft during the past 10 years. These fibers become the "adhesive" or bonding agent after being subjected to high temperature. Some of these fibers are made with a sheath/core arrangement where one polymer is on the inside with another on the outside that will melt at a lower temperature. Two or more different fibers can also be added to the typical polyester blend and the olefin can become tacky and bond all the fibers into a web without affecting the polyester fibers.

The largest highloft market for many years has been glass insulation and it continues to hold that position today. This three billion pound end use has gone unnoticed by most in the nonwovens industry. It is one of the oldest processes in concept although many innovations and improvements have been made. The glass is melted and formed into filaments and fibers in a continuous operation. Binders can be applied during the operation to offer additional stability to the nonwoven batt. While glass has dominated the building and many industrial insulation markets, nonwovens using other fibers have been growing in some of these markets during the past few years.

A major problem for glass as well as many other highloft nonwovens has resulted from its major characteristic. The amount of air or voids that are inherent in these products makes them costly to store and move. A 30 foot trailer loaded with polyester fiberfill can contain less than 3000 pounds. The air or voids also means there is a significant amount of oxygen in the product when it comes to burning. Removing the air by compression, flame retardant fibers and binders and other methods are currently reducing this concern.

The advantages of highloft materials by far exceed the disadvantages for the foreseeable future. Such giant markets as insulation, filtration, healthcare, sorbents, roofing and geotextiles are continuing to grow and nonwovens are increasing their position in these and other markets. The versatility of nonwovens has by no means been exhausted. Each year we have new and different machines, raw materials and most of all, new ideas in utilizing these capabilities. In the future we will see much more complicated products that not only offer answers to the customer's requests but also offer the opportunity to reduce converting and fabricating costs, mold or form, resist abuse and exceed the requirement of regulations and standards.

As we gain knowledge and ability to use the many raw materials available, we will see sales increase in existing markets and many new markets will be developed. Selected combinations of fibers, chemicals, foam, film, cellulose and superabsorbents will allow the highloft manufacturer to offer sophisticated and high tech products. Laminates and saturated materials will also add new products and markets.

NONWOVEN PROCESSES THAT

PRODUCE HIGHLOFT PRODUCTS

Airlaying Blowing Card/Garnetting Extrusion Melt Blowing Needlepunching Spunbonding Spunlacing Stitchbonding

PROPERTIES OF HIGHLOFT

NONWOVENS

Abrade Absorb Aesthetics Barrier Beautify Clean Conform Containc Ccover Cushion Fill Filter Flex Insulate Porous Protect Resilient Retain Soft Stiff Strength Support Wick

ALPHABETICAL LISTING OF MAJOR HIGHLOFT END-USE MARKETS

Abrasives Absorbent Acoustical Materials Agriculture Apparel

Insulation

Interlining

Padding Applicators Athletic & Sports Automotive

Carpet

Door Panel

Filters

Firewall

Headliners

Kick Panels

Joining Materials

Truck Liners

Window Shelves Bags Bandages Bedding

Blankets

Comforters

Mattresses

Mattress Pads

Mattress Tops

Pillows

Spread/Quilts Buffing Pads Carpet Ceiling Tiles Civil Engineering Cleaning Pads Clothing Containers Costumes Covers, Protective Crafts Curtains Cushions Decorative Diapers Door Mats Draperies Face Masks Filters

Air, Beverage

Chemical, Food, Furnace

Gas, Milk, Oil

Paint, Plastic Flotation Media Furniture

Cushion Wrap

Insulator

Padding

Pillows Gaskets Gauze Geotextiles Glove Liners Hats Head Rests Health Care

Underpads

Incontinence

Insulation Horse Blankets, Pads Ironing Board Pads Knee Pads Laminated Plastic Lens Cases/Carriers Luggage Marking Pens Medical Mops Nursing Pads Oil Sorbants Protective Packaging Paint Applicators Parade Floats Pipe Insulation Polishing Pads Pot Holders Pultrusion Plastic Substrate Road Patches Road Underlay Roofing Sanitary Napkins Shoe & Boot Liners Sleeping Bags Sound Insulation Sound Proofing Synthetic Leather Tablecloths Tampoons Thermal Insulation Toys Undergarments Wall Coverings Wash Cloths Wicks Wiping Cloths

Tom Holliday is a well known consultant to the nonwovens and textile industries and a frequent contributor to NONWOVENS INDUSTRY. Mr. Holliday is also the organizer, in cooperation with INDA, of this month's of INDA Highloft Conference, which takes place May 18-19 in Charlotte, NC. Mr. Holliday operates his consultancy firm, Thomas M. Holliday & Associates, out of his office at 25 Edgewood Road, Yardley, PA 19067,215-493-2501.
COPYRIGHT 1993 Rodman Publications, Inc.
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Copyright 1993 Gale, Cengage Learning. All rights reserved.

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Author:Holliday, Tom
Publication:Nonwovens Industry
Date:May 1, 1993
Words:2243
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