Saturday, February 3, 2018

Napped Fabrics – Part I [1]
Art Resource

Marie-Therese Wisniowski

Preamble
This is the seventy-third post in the "Art Resource" series, specifically aimed to construct an appropriate knowledge base in order to develop an artistic voice in ArtCloth.

Other posts in this series are:
Glossary of Terms
Units Used in Dyeing and Printing of Fabrics
Occupational, Health & Safety
A Brief History of Color
The Nature of Color
Psychology of Color
Color Schemes
The Naming of Colors
The Munsell Color Classification System
Methuen Color Index and Classification System
The CIE System
Pantone - A Modern Color Classification System
Optical Properties of Fiber Materials
General Properties of Fiber Polymers and Fibers - Part I
General Properties of Fiber Polymers and Fibers - Part II
General Properties of Fiber Polymers and Fibers - Part III
General Properties of Fiber Polymers and Fibers - Part IV
General Properties of Fiber Polymers and Fibers - Part V
Protein Fibers - Wool
Protein Fibers - Speciality Hair Fibers
Protein Fibers - Silk
Protein Fibers - Wool versus Silk
Timelines of Fabrics, Dyes and Other Stuff
Cellulosic Fibers (Natural) - Cotton
Cellulosic Fibers (Natural) - Linen
Other Natural Cellulosic Fibers
General Overview of Man-Made Fibers
Man-Made Cellulosic Fibers - Viscose
Man-Made Cellulosic Fibers - Esters
Man-Made Synthetic Fibers - Nylon
Man-Made Synthetic Fibers - Polyester
Man-Made Synthetic Fibers - Acrylic and Modacrylic
Man-Made Synthetic Fibers - Olefins
Man-Made Synthetic Fibers - Elastomers
Man-Made Synthetic Fibers - Mineral Fibers
Man Made Fibers - Other Textile Fibers
Fiber Blends
From Fiber to Yarn: Overview - Part I
From Fiber to Yarn: Overview - Part II
Melt-Spun Fibers
Characteristics of Filament Yarn
Yarn Classification
Direct Spun Yarns
Textured Filament Yarns
Fabric Construction - Felt
Fabric Construction - Nonwoven fabrics
A Fashion Data Base
Fabric Construction - Leather
Fabric Construction - Films
Glossary of Colors, Dyes, Inks, Pigments and Resins
Fabric Construction – Foams and Poromeric Material
Knitting
Hosiery
Glossary of Fabrics, Fibers, Finishes, Garments and Yarns
Weaving and the Loom
Similarities and Differences in Woven Fabrics
The Three Basic Weaves - Plain Weave (Part I)
The Three Basic Weaves - Plain Weave (Part II)
The Three Basic Weaves - Twill Weave
The Three Basic Weaves - Satin Weave
Figured Weaves - Leno Weave
Figured Weaves – Piqué Weave
Figured Fabrics
Glossary of Art, Artists, Art Motifs and Art Movements
Crêpe Fabrics
Crêpe Effect Fabrics
Pile Fabrics - General
Woven Pile Fabrics
Chenille Yarn and Tufted Pile Fabrics
Knit-Pile Fabrics
Flocked Pile Fabrics and Other Pile Construction Processes
Glossary of Paper, Photography, Printing, Prints and Publication Terms
Napped Fabrics – Part I
Napped Fabrics – Part II
Double Cloth
Multicomponent Fabrics
Knit-Sew or Stitch Through Fabrics
Finishes - Overview
Finishes - Initial Fabric Cleaning
Mechanical Finishes - Part I
Mechanical Finishes - Part II
Additive Finishes

The Glossary of Terms, Timelines of Fabrics, Dyes and Other Stuff, A Fashion Data Base, the Glossary of Colors, Dyes, Inks, Pigments and Resins, the Glossary of Fabrics, Fibers, Finishes, Garments and Yarns, Glossary of Art, Artists, Art Motifs and Art Movements and the Glossary of Paper, Photography, Printing, Prints and Publication Terms have been updated in order to better inform your art practice.

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Introduction
The average consumer – as well as some writers who might not be well grounded in textile information – confuse the terms “napped” and pile. These are very different fabric effects. As we have already dealt with how pile fabrics are made, this post and the next post in this series will explain how napped fabrics are made.

Napped cotton fabric costume: navy captain costume, navy dance fancy dress.


Process of Napping[1]
Nap consists of a layer of fiber ends, on the surface of a cloth, that are raised from the ground weave by a mechanical brushing action. Thus napped fabrics are literally “made” by a finishing process. The figure below shows a fabric before and after napping.

Fabric before and after napping.

Napping was originally a hand operation in which the napper tied together several teasels (dried thistle-like vegetable burs, shown in the figure below) and swept them with a plucking motion across the surface of the cloth to raise fibers from the ground weave.

A teasel: yarn before and after napping.

The teasels had a gentle action and the barbs would break off before causing any damage to the cloth. The raised fibers formed a nap that completely changed the appearance and texture.



Teasels are still used in the machine finishing of defined wool fabrics such as duvtyn. For machine processing (gigging) they are mounted on rollers and as the barbs wear off or break off, the worn teasels are replaced by new ones. The fabric may be either wet or dry.

Wool napped cotton fabric.

Most napping is now done by rollers covered by a heavy fabric in which bent wires are embedded.

Napping rolls. Left: Counter pile. Right: pile roll.

Napping machines may be either single-action or double-action.

Fewer rollers are used in the single-action machine. They are all alike and travel at the same speed. They are called pile-rolls and the bent ends of wires point in the direction in which the cloth travels but the rollers rotate in the opposite direction. These rollers are all mounted on a large drum or cylinder, which rotates in the same direction as the cloth. The pile-rolls travel faster than the cloth in order to do any napping.

In the double-action napping machine every other roll is a counter-pile roll. This roll has wires, which point in the direction opposite to those of the pile-roll. The counter-pile roll must travel slower than the cloth in order to produce a nap. When the speed of the rolls are reversed (pile-rolls at slower speed and counter-pile rolls at faster speed) a “tucking” action occurs. Tucking pushes the raised fibers back into the cloth and makes a smooth surface.

Napping machine.


Reasons for Napping
1. Warmth. A napped surface and the soft twist of the filling yarn increase the dead air space. Still air is one of the best insulators.
2.Softness. This characteristic is especially important in baby cloths.
3.Beauty. Napping adds much to a fabrics attractiveness.
4.Water and stain repellence. Fiber ends on the surface cut down on the rapidity with which the fabric gets wet.


Quality, Characteristics and Care
The amount of nap does not indicate the quality of the fabric. The amount may vary from the slight fuzz of Viyella flannel to the very thick nap of imitation fur.

Viyella Skirt. Material: 20% Polyamide, 80% Wool.

Faux fur blanket for babies basket stuffer. Long nap Mongolia fur.

Short compact nap on a fabric with firm yarns on a closely woven ground will give best wear. Stick a pin in the nap and lift the fabric. A good durable nap will hold the weight of the fabric. Hold the fabric up to the light and examine it. A napped surface may be used to cover defects or a sleazy construction. Rub the fabric between the fingers and then shake it to see if the short fibers drop out. Thick nap may contain flock (very short wool fibers). Rub the surface of the nap to see if it is loose and will rub up in little balls (pilling). Notice the extreme pilling on the sweater below.

Pilling on a wool sweater.

Some napped fabrics have an up and down. To test this, brush the surface of the fabric. Brushing against the nap roughs it up and causes it to look darker because more light is being absorbed. This is the “up” direction of the fabric. When the nap is smoothed down, the reflection of light from the surface gives a lighter shade of color. Napped fabrics should be made with the nap “down” so garments will be easier to brush. However, the direction of the nap is not as important as the fact that the same direction of nap is used in all parts of a garment.

With the nap running up the fabric looks darker and more saturated with color. With the nap running down it looks lighter and the color is softer.

Low-count fabrics usually have low-twist yarns; and when strain is applied, the fibers slip past one another and do not return to their original position. Thus garments tend to “bag” in the seat and elbow areas. Tightly twisted yarns are more resistant to bagging. It is best to line low-count fabrics or to make the garment with gored or flared skirts.

Wear on the edges of sleeves, collars, buttonholes and so forth, causes an unsightly contrast to unworn areas. Very little can be done to it except that a vigorous brushing will give a fuzzier appearance. Price is no indication to resistance to wear, since the more expensive wool fibers are finer and less resistant to abrasion. Wear will flatten the nap but if the nap is still present on the fabric it can be raised by brushing or steaming. Loosely napped fabrics will shed short fibers on other garments or surfaces. They also shed lint in the wash water so should be washed separately or after other articles are washed. Napped fabrics are fluffier if dried on a breezy day or dried in a dryer.


Construction
Napped fabrics must be made from especially constructed gray goods in which the filling yarns are made of low-twist staple (not filament) fibers.

Napped fabrics.

The difference in yarn structure makes it easy to identify the lengthwise and crosswise grain of the fabric. The figure below shows warp and filling yarns from a camel’s hair coat fabric, before and after napping.

A teasel; yarn before and after napping.

Fabrics can be napped on either or both sides. The nap may have an upright position or it may be “laid down” or “brushed”. When a heavy nap is raised on the surface, the yarns are sometimes weakened. Wool fabrics are fulled or shrunk to bring the yarns closer together and increase fabric strength.

Heavy napped fabric.

Yarns of either long- or short-staple fibers may be used in napped fabrics. Worsted flannels, for example, are made of long-staple wool.

Heather gray worsted wool flannel cinch pants.

The short-staple fiber yarns used in woolen flannels have more fiber ends per inch, and thus can have a heavier nap. In blankets, which are heavily napped for maximum fluffiness, a fine cotton (core) ply is sometimes used in the yarn to give strength.

Men’s Buffalo check woolen flannel shirt.

Although napped fabrics can be made of any staple fiber, they are most frequently made of cotton, rayon, wool or the acrylic fibers. Pilling and attraction of lint due to the electrostatic properties are problems with nylons and polyesters.

100% Polyester soft napping warp knitting print dye coral fleece fabric for baby blanket.

Napped fabrics may be plain weave, twill weave or knit. More filling yarn is exposed on the surface in a 2/2 twill or a filling-faced twill, therefore a heavier nap can be raised on twill fabrics. The knit construction in napped fabrics is often used for articles for babies. Some brands of coats are always made of napped knit fabrics.

H2H SPORT men’s active zip-up slim fit napping knit jacket with zip pockets.

Napping is less expensive than pile weave as a way of producing a three-dimensional fabric. The name flannel is almost synonymous with the word napped. When the name is used alone it implies wool fiber content. If the fabric is made of fiber other than wool, a descriptive adjective is used with the word flannel – for example, cotton flannel.

Boys' cotton flannel shirt in color-block plaid.

Flannel is an all-wool napped fabric made in dress, suit or coat weights. It may be made with either worsted or woolen yarns. They may be yarn-dyed.

Cardigan: yarn dye flannel for women.

Worsted flannels are important in men’s suits and coats and are used to a lesser extent in women’s suits and coats. They are firmly woven and have a very short nap. They wear well, are easy to press, and hold a press well.

A grey three-piece plaid suit in luxury British worsted wool flannel is a staple for cool fall weather.

Woolen flannels are fuzzier, less firmly woven fabrics. Many have been given a shrinkage control treatment, which alters the scale structure of the fiber. Because this causes some weakening of the fabric, 15 to 20 per cent nylon is blended with the wool to improve the strength. These fabrics do not take or hold sharp creases so are best when used in less tailored garments.

Vintage 70s - wool nylon flannel red plaid shirt.

Fleece is a coat-weight fabric with long brushed nap or a short clipped nap. Quality is difficult to determine.

Women’s silken fleece jacket.

Cotton flannels flatten under pressure and give less insulating value than wool because cotton fibers are less resilient. The fibers are also shorter, thus there is more shedding of lint from cotton flannels. The direction of nap (up and down) is relatively unimportant in these fabrics because in many, the nap is very short, and also because their chief uses are for robes, nightwear, baby clothes and sweat shirts.

Cotton flannel robe.

Flannelette is a plain-weave fabric, which is converted from grey-goods fabric called soft-filled sheeting. It is napped on one side only, has a short nap and a printed design, unless it is white. The nap will form small pills and is subject to abrasion; Suede and duvetyn are also converted from the same grey goods but are sheared close to the ground to make a smooth, flat surface. Duvetyn is the lighter weight of the two.

Pilgrim flannelette shirt.

Outing flannel is a yarn-dyed fabric (or white) which is similar in fabric weight and length of nap to flannelette but is napped on both sides.

Festive outing flannel.

As the warp yarns in both fabrics are standard weaving yarns, it is easy to identify the grain of the fabric.

Rayon flannel is widely used in dresses and suits. It is similar in appearance to worsted flannel but is much less expensive. It is usually a blend of rayon and acetate.

1950's rayon flannel plaid red grey flecked day dress.


Reference:
[1] N. Hollen and J. Saddler, Textiles, 3rd Edition, MacMillan Company, London (1968).

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