Study of fabrics

Front matter

LIBRARY OF THE NEW YORK STATE COLLEGE OF HOME ECONOMICS

CORNELL UNIVERSITY ITHACA, NEW YORK

The original of this book is in the Cornell University Library.

Preface

The object of this book is to give the reader a knowledge of the various textile 'fibers, their properties in regard to warmth and hygiene, their cleansing and laundering possibilities ; and such understanding of the processes of manufacture as will enable her to judge, intelligently, good and bad materials, adul terations, prices, weaves, etc. Upon woman devolves the responsibility of the economical expenditure of the family income ; it is her duty to know that she is receiving the worth of her money, and, yet, most women are dependent upon the word of the clerk, very often far more ignorant than the purchaser. The standard of materials will never be raised to its proper level, until the consumers are intelligent enough to make the demand.

A detailed study is made of each of the. common textile fibers used for household purposes — cotton, linen, wool, and silk — taking up the growth, manufacture, physical, and chemical properties with special emphasis on the practical household tests which may be used in detecting adulterations and judging of the quality. Laundry problems are discussed at some length dealing with the cleansing agents commonly used in the laundry and the principles which should govern a choice of the method best suited to individual conditions. Removal of stains and dry

PEEFACE

cleaning are treated in a simple, untechnical way. One chapter deals with the economic side of the clothing problem. Suggestions are given as to the most economical ways of spending the clothing allowance, the proportion of the income which should be spent for clothing, and there is some discussion of clothing budgets. Only pre-war prices are given in this book and they can be considered only as a basis of comparison.

Annabell Turner.

Contents

CHAPTER PAGE

I. Cotton 1

II. Wool 30

CHAPTER I Evolution of Spinning and Weaving.— The

textile art is older than man, for, long before he came upon earth, spiders and caterpillars spun their threads, birds wove their nests, and certain trees fabricated a kind of cloth by closely interweaving the fibers of their inner bark. Man gradually conceived the idea of using this bark for clothing by soaking it in water and beating it with wooden mallets to felt the fibers together. It was then dried and bleached in the sun and colored with vegetable dyes, the method of coloring being to lay a leaf or flower on the dye and, as soon as the surface was covered with the dye, to press it down on the cloth, thus fixing the design. The bark most used for this "Tapa cloth," as it is called, was that of the paper mulberry.

Perhaps the interlacing of the barks suggested other possibilities to the people of that day, for they began rudely to weave together reeds, rushes, and twigs to form baskets and

Girl Spinning

mats, expressing their conception of art and beauty by combinations of color and weave. Beautiful examples of primitive weaving are found in northern South America, Africa, and among the western Indians.

It was with the discovery of spinning yarn that the true textile art began, and although there is no authentic information as to the actual time of the origin pf spinning, we do knowthat it dates- back before 2,000 B. C. Early nomadic tribes used threads to fasten together the skins which they used as clothing — perhaps wool torn from the sheep in passing bushes and brambles may have suggested it to them.

Until 1,500 A. D. all spinning was done by hand and a spindle, which was at first merely a stick upon which the thread was wound. Later it was discovered that the spindle could be whirled around faster if it had a weight on the end, so a piece of wood was attached to the lower end. This was called the whorl. The need of something to fasten the wool to, brought about the distaff, a stick around which the wool was wrapped and then held in the hand or tucked in the belt.

At the end of the fifteenth, or beginning of the sixteenth, century a one thread machine was invented which enabled the spinner to produce seven times more yarn than by the distaff and spindle. Gradually improvements and new inventions followed, so that today most of the spinning has been taken from women's hands and is produced by means of machinery.

4 THE STUDY OP FABRICS

The weaving of the spun yarn came as a natural sequence to the discovery of spinning. Linen cloth of exquisite fineness of thread and

Throwing the Shuttle through the Warp Shed by Hand evenness of weave is found in old Egyptian tombs, and the early Greeks and Romans produced woolen fabrics of great beauty and firmness. Manufacture of both wool and flax existed in Greece in the days of Homer.

The early Egyptian loom was a vertical frame similar in idea to the tapestry loom. Some savage tribes stretched the warp threads between convenient objects on the ground or from horizontal supports and wove back and forth between the warp threads as in darning. Many modifications have come since the early days but the same three steps to the process of weaving remain, whether the weaving be done on the crudest of hand looms or upon the most modern machinery: (a) shedding, the lifting of certain warp threads, thereby making a space, or shed, through which the shuttle is passed; (b) picking, passing the shuttle through the threads; and (c) battening, pressing the weft thread against the preceding ones to make the cloth firm and even.

Paets of a Loom

1. Loom,. — An arrangement for spreading a warp and keeping it in order for weaving.

2. Raddle. — An implement used for spreading the

warp evenly.

3. Beams. — (a) Warp beam, used for winding up the

warp threads.

(b) Cloth beam, used to wind up the finished, woven material.

4. Leash. — Loops through which threads are passed to

give pattern to the weave.

5. Heddle. — A collection of heddles.

6. Shed. — The opening made in the warp for the pas-

sage of the shuttle — produced by the heddle.

7. Shuttle. — A tool used for carrying the weft.

8. Reed. — A comb-like instrument for keeping warp

even and beating the weft together.

9. Tenterhooks. — Contrivances to hold the warp even

on the sides.

Cotton.— The cotton plant belongs to the natural order of Malvaceae, or mallow family, and is known scientifically by the generic name "Gossypium." It is a shrub which reaches a height of from four to six feet, and is indigenous principally to islands and sea-coast regions of the tropics, although it can be cultivated up to about 37° on either side of the equator. A warm, humid climate and sandy soil are most favorable to its growth.

There are many varieties of the cotton plant, the most important being: (a) Gossypium herbaceum, which grows from 4 to 6 feet in height and bears a yellow flower. The seeds are covered with a short gray down and the fiber is short. This variety is found in Egypt, Asia Minor, Arabia, India, and China, (b) Gossypium arbareum, which grows to a height of from 15 to 20 feet. The seed is covered with a greenish fur and is enveloped in a fine silky down, yellowish white in color. It is found in Egypt, Arabia, and China, (c) Gossypium barbadense, which grows from 6 to 15 feet high. The flowers are yellow and the seeds black and smooth, being destitute of the hair that characterizes other cottons. It is a native of the Barbadoes, from which it derives its name. The best quality cottons come from this species— Sea Island and Florida cottons — from which are spun the finest yarns. Long-stapled Egyptian cotton is supposed to have come from this stock. The chief cotton countries of the world in order of importance are: United States, India, Egypt and Brazil, "West Indies, West Coast of Africa, Asia, Asia Minor, China, and Queensland.

In the southern states cotton is planted with a machine, the seeds being dropped in a continuous stream. When the young plant is about three inches high it is thinned out with a hoe — about twelve inches being left between plants. The time for planting depends upon the latitude, beginning about the middle of March and ending the first half of May.

Ten or eleven weeks after the planting, the shrub is ready to bloom. The flower has live petals, yellow at the base and growing lighter in color at the edges. When the flower drops off, a dark green pod is seen which increases in size and finally discloses a mass of downy white fibers in which are imbedded the dark brown or black seeds. The cotton is picked as soon as ripened and separated from the seeds by a process known as ginning. The seeds are hulled and the kernel put through a hydraulic press which squeezes all the oil from it, leaving the meal, which is used as feed for cattle. The refined oil is used as a substitute for olive oil, the residue being used as soap stock.

After the cotton is ginned it is baled and shipped to the mill, the standard size of a cotton bale in the United States being 56 by 24 by 32 inches and weighing about five hundred pounds. The bales are wrapped in bagging and strapped with sheet-iron bands. When the cotton ar-

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F ' ill l l rives at the mill the bales are broken and the cotton starts upon its journey, passing through various processes until it is converted into yarn. The first step consists in giving the cotton a thorough cleaning, which is accomplished by a series of machines which pull the wads of cotton into shreds, beat out the dirt and any seeds left in, and finally leave the cotton in the form of batten upon the cylinders. From here the cotton goes to the carding machine where it is combed to straighten the fibers and remove any remaining foreign material and also some of the short fibers. Then it goes into the combing machine which casts aside as waste all fibers below a certain length, passing the rest on to the drawing machine where the fibers are laid perfectly straight and parallel and the cotton drawn out as much as possible without breakage. The combing process is omitted unless the cotton is being prepared for especially fine or high grade materials.

Several intermediate steps take place before the fiber is spun into yarn, the principal point of difference being the amount of twist imparted to the strand. Spinning produces the finished yarn, which is converted into thread by uniting two or more yarns firmly by twisting. All sizes of 6-cord threads are made of six strands and 3-cord spool cotton is made of three strands. The ordinary spool of cotton thread contains 200 yards.

Before being woven into cloth, cotton threads are strengthened by coating them with a preparation of starch, flour, paraffin, tallow, etc., to enable them to withstand the friction resulting from the weaving process without breaking. After weaving, the material is bleached, starched, and calendered, the object of the last process being to give it a perfectly smooth and even surface and also to impart a luster to the cloth as it passes through. The cloth is calendered several times, according to the finish required.

Cotton is dyed either in the yarn or in the cloth, but it has much less affinity for dyestuff s than animal fibers, and, relatively speaking, there are only a few with which it can be dyed without the assistance of a mordant.

Physical Characteristics.— -Under the microscope the cotton fiber usually presents the appearance of a flat, slightly twisted ribbon with thickened edges.] Physically the individual cotton fiber consists of a single long cell with one end attached directly to the surface of the seed. While it is growing, the fiber is round and cylin-

Ttpbs of Cotton Fibers

1. Glossy, dead, structureless fiber;

2. Thin, transparent, flat, unripe fiber;

3. Half ripe fiber with thin cell wall;

4. Mature, ripe fiber with full twist and thick, well-defined cell wall.

drical, having a central canal running through it, but after the pod has ripened and burst the cell wall collapses, causing the fiber to form into a flat, ribbon-like band. Upon ripening, the juices in the inner tube dry up, causing the characteristic spiral twist of ripe cotton. This spiral twist makes cotton valuable for spinning purposes as it causes the fibers to lock around each other more tightly. In diameter the cotton fiber is rather even for the greater part of its length, gradually tapering to a point at its outgrowing end. The lengths of different varieties of cotton fibers vary from three-fourths to two and one-half inches, sea-island cotton being the longest.

. The hygroscopicity, or power to absorb water without feeling damp, is between six and eight per cent of its weight. Cotton which has been freed from the natural vegetable wax is more hygroscopic, and is known as absorbent cotton.

Linen has the greatest power of heat conduction and cotton ranks second. Materials made from linen are, therefore, the coolest and cotton materials come next.

Though resistant to the action of moths and insects in general, cotton is liable to undergo fermentation, as is evidenced by the formation of mildew on cotton fabrics stored in warm, damp places.

Chemical Nature of Cotton. — In its chemical composition, cotton consists almost entirely of cellulose, on the surface of which is a protecting layer of wax which is removed in one boiling out and bleaching process performed previous to the dyeing and printing of the cotton.

Effect of Chemicals on the Fiber. — Organic acids and their salts, such as acetic acid in vinegar, oxalic in rhubarb, tartrates in grapes, and citrates in lemons, even when moderately concentrated, do not appear to have any injurious effect upon the cotton fiber unless they are allowed to dry on the fabric and are afterwards moistened and ironed dry with a hot iron. The destructive action is not so much of a chemical nature as mechanical, it being caused by the acids crystallizing within the fiber and breaking the cell wall. Dry heat in connection with organic acids is more injurious than moist heat. Very dilute solutions of mineral acids, if cold, have no appreciable effect upon cotton, but if the fiber is impregnated with such a solution and allowed to dry rapidly it becomes tender due to the concentration of the acid induced by the evaporation of water. Heat will cause dilute mineral acids to attack the fiber much more readily than otherwise. In all dyeing and bleaching operations, therefore, where the use of acid may be required, the temperature of the acid baths should not be above 70° F., nor should a solution greater than two per cent be used. Organic acids should be substituted for mineral acids wherever possible, and all of the acid should be removed from the cotton or neutralized before drying or there is danger that the material may be ruined.

Action of Alkalies on Cotton. — Alkalies have a very different effect upon the cotton fiber from that of acids. Under ordinary conditions they are harmless. Dilute solutions of either the carbonated or caustic alkalies even at a boiling temperature have little if any injurious effect on the cotton fiber.

Concentrated solutions of caustic alkalies have a peculiar effect upon cotton. If the fabric is immersed for two minutes in a strong solution of caustic soda and is then removed at once and washed free of the alkali, it is found to have shrunken greatly and to have become much closer and firmer in texture, the cloth having actually been strengthened by the shrinkage. Long-continued action in concentrated alkaline solutions, however, will gradually destroy the cloth.

Bleaching Agents. — Formerly linens and cottons were bleached entirely by slow oxidation due to action of water, air, and sunlight, but various artificial bleaching stuffs have been discovered which hasten the process and save both time and labor. A common household bleach, chloride of lime (a "bleaching powder") is a compound of chlorine (a gas) with calcium oxide. This powder has the power of destroying colors and stains at once but it also attacks the fibers of the material unless the action is neutralized by rinsing the cloth in some alkaline solution. Ordinary household ammonia, or hyposulphate of soda will do this satisfactorily.

The can in which the chloride of lime is kept should not be allowed to stand uncovered, as the chemical will rapidly lose its strength.

Another bleaching agent much used for household purposes is Javelle water, which is similar to "bleaching powder" except that soda replaces the lime. It is prepared by dissolving 1 Ib.-of washing soda in a quart of boiling water, allowing it to cool. Then half a pound of bleaching powder is dissolved in two quarts of cold water, allowed to settle, and the clear liquid added to the soda. The whole is strained off, bottled, and kept in a dark place. As in using bleaching powder, rinsing in a neutralizing solution is necessary. Both should be kept in glass bottles having glass or rubber stoppers.

Mercerised Cotton. — The process of mercerization is named after John Mercer who discovered in 1844 that cotton might be given a high degree of luster and at the same time be strengthened by subjecting it to the chemical action of caustic alkali and a strong tension to prevent contraction.

When the cotton fiber is placed in the caustic solution it undergoes a peculiar physical modification, changing from the flat, twisted, ribbon-like shape to a smooth, rounded, cylindrical fiber with thickened cell wall. The tensile strength is greatly increased, amounting in some cases to from 30% to 50%.

Mercerization imparts a high luster to the cotton fiber, due partly to the fact that the fiber, being cylindrical, reflects the light instead of absorbing it, and to another condition which affects the lustrous appearance, the change in the cell elements. The substance becomes gelatinous and translucent, thereby affecting the optical properties of the fiber and lessening the amount of light absorbed. Ordinarily the process of mercerization is not continued until every

Cotton, Mercerized and Stretched, Showing Incomplete Mercerization

fiber is completely mercerized. The illustration, which is typical, shows part of the fibers still containing a partial twist.

Mercerized cotton is somewhat more reactive towards dyestuffs than other cottons.

Yarns of ordinary grades of cotton cannot be mercerized successfully, and as the cost of producing high grade mercerized yarn is about three times that of the same quality *of unmercerized cotton, the higher cost of the finished product may readily be understood. Long-stapled sea-island cotton and Egyptian varieties are usually selected for the manufacture of mercerized materials, as they are better able to withstand the tension necessary for the perfection of the process than the short-stapled fibers.

Cotton may be mercerized either in the yarn or in the cloth, although it is usually done in the yarn.

Silk Finish. — Both mercerized and unmercerized cottons are often calendered to increase the luster of the material. The cloth is passed between rollers, under heavy pressure, one roller being engraved with obliquely set lines (125- 600 to an inch). The larger number of very fine parallel surfaces reflect the light producing a beautiful silk like luster.

Unmercerized cotton which has been finished this way is no stronger than ordinary cotton. To distinguish between the mercerized material and goods which has been merely calendered place a piece of the material under the lowest power of the microscope and turn it backward and forward. Look for press lines on the fibers.

A Test* for Mercerized Cotton. — Wash the samples, rinse well, and when dry compare with a piece of the same which has not been washed. If the luster remains, the material was mercerized. The finish put on by sizing material, pressure, and calendering is removed by washing.

Experiment.— Select a number of samples of cotton materials which have a lustrous finish and use the test given above to determine which are mercerized and which have simply been treated to make them appear mercerized.

Dyeing. — Dyestuffs are classified in general as acid, basic, substantive, and mordant dyes. The acid dyes may be used to dye animal fibers directly — that is, without the use of a mordant. Basic dyes are" used directly on animal fibers and may be used on cotton if tannin is used as a mordant. The substantive dyes will be absorbed by both animal and vegetable fibers, although they are usually used on cotton. The mordant dyes require a metallic mordant for both animal and vegetable fibers.

The word mordant comes from a word mean-

22 THE STUDY OF FABKICS

ing ' ' to bite. " It is a substance which will unite with the fiber and also with the dye to be used.

Silk and wool have both acid and basic properties and, therefore, the acid and basic dyes may be used directly on these fibers. As cotton and linen are inactive chemically, these dyes will not unite with the vegetable fibers unless a mordant is used. This accounts for the fact that cotton and linen are more difficult to dye than wool or silk.

Natural dyestuffs are no longer used commercially to any extent. The following are used occasionally: Madder for red, logwood with fustic for black, cutch for brown, and indigo for blue. Madder and indigo are now produced artificially instead of being obtained from their natural sources. This has reduced their cost materially.

The usual process of dyeing i*s, first, to treat the cotton goods with a mordant (various salts of aluminum, chromium, iron, tin, and copper), fixing it on the fiber by means of tannin or an alkali. The mordanted cloth is put into a dye bath and boiled one or more hours until the desired shade is obtained. The salts of aluminum are used as mordants for the light shades and iron for the dark ones. In general, chromium mordants give fastest dyes. Aniline dyes, made from anilin, a coal-tar product, are largely used at the present time, and if care is taken in their use, prove satisfactory. The commercial dyes which may be purchased for home dyeing are derivatives of coal-tar products and good results may be obtained if the directions are followed carefully. The colors are more permanent than those obtained with the natural dyes. Printing. — Block printing was first used, the design being engraved in relief on blocks of wood. These were dipped in the colored paste and applied to successive portions of the cloth by hand. These blocks are now replaced by engraved copper rolls, the design being such that it is repeated once or a number of times in each revolution of the cylinder. There is a printing roll for each color of the design. Sometimes both the background and the design are printed on the cloth, but the more common process is for the design only to be printed on the cloth, which may be dyed afterwards. In the paste of the printed design there is some chemical which prevents the portions printed from taking the dye, consequently these remain white or a different color as the case may be. This is called the "resist" process. Another process is to first dye the cloth and then print on some chemical which, when the calico is steamed, discharges the color. This is called the "discharge" process. Sometimes this weakens the goods in many places where the color has been discharged. This accounts for the dropping away of dots and also the giving way of white stripes in printed materials. The color paste contains both the dye and the mordant. After calico has been printed it is steamed to develop and fix the color, washed to clear the whites, usually sized, then pressed and dried by passing over slowly revolving, steam heated drums. In general the colors in printed materials are not so fast to washing and sun as are those dyed in the piece or yarn.

Common Cotton Materials

Gingham. — Cotton dress goods woven of plain dyed yarn, usually in cheeks, plaids, or stripes

Muslin. — White, firmly woven material suitable for underwear and sheeting

Calico. — Material with a figured design printed on one side

Cambric— Fine material used for dresses, usually white, but sometimes printed on one side

Batiste. — Fine dress material, either white or printed

Dimity. — Sheer, fine material, corded lengthwise, usually, but sometimes both ways

Sateen. — Cotton fabric with a glossy surface somewhat resembling satin

Pique. — Heavy fabric, corded either lengthwise or crosswise, used for waists and suitings

Mull. — Thin, white, wiry fabric used as a dress material

Nainsook. — A soft, white, cotton fabric used for infant's clothing, lingerie, dress goods, etc.

Organdie. — A fine, sheer, wiry dress material, either in plain colors or printed designs

Percale. — A firm material used for skirts and dresses, usually printed on one side

Scrim. — An open weave used for curtains

Corduroy. — A cotton material resembling velvet but woven with a ribbed effect

Velveteen. — Cotton velvet which has a loose pile on the surface

Testing for Fastness to Sunlight. — Cover one end of a sample of material with a piece of heavy cardboard and expose the uncovered end to the sunlight for a number of days, examining it in the shade to see if the exposed end has changed in color from that of the covered part. Note the number of days it takes to change the color. Fabrics that are but slightly changed at the end of a month are called "fast," "moderately fast" colors are those but slightly faded in 14 days, and those which are more or less completely faded in 14 days are called "fleeting."

Testing for Fastness to Washing. — Fabrics should withstand the action of soap, the heat, and the mechanical friction necessary for laundering. To test the fabric wash it in a soap solution similar to that used in the household, not warmer than 131° F. Repeat several times, and if the color does not fade it is "fast" to washing.

Testing for Crocking. — Many dark colored cottons which have been poorly dyed discolor other garments or the skin. Materials may be tested easily by rubbing them briskly on white unstarched cotton fabric.

Testing for Fastness to Perspiration. — The fabrics which come in contact with the body are often weakened by perspiration unless a good resistant material is used. To test the fabric for resistance, place a sample in a bath of 25% to 40% acetic acid warmed to the temperature of the body, 98.6° F. Dip the sample a number of times and dry without rinsing between clean blotting papers. Note whether or not the color is affected.

Testing for Percentage of Shrinkage. — Pour boiling water over a sample and leave it immersed over night. Dry at a moderate temperature without stretching. Press. Measure before and after treatment. Try samples of lavender, pale blue, pink, green, and brown, to show: (a) Fastness to sunlight, (b) Fastness to laundering.

Wearing Qualities Compared with Price. — Cotton, being cheapest, is not adulterated with any of the other fibers, but an inferior grade of material is often made to appear heavier by the addition of dressing. Starch, glue, dextrine, etc., are used, and they may add greatly to the weight of the cloth. The spaces between threads are filled and a good finish is given to the material, but after washing, the cloth loses both in weight and firmness. This dressing may be detected in thin fabrics by holding them up to the light, then the starch will show between the threads. It may also be detected by rubbing the material in the hands when it is freed from part of the dressing and the firmness of the cloth may be determined. Still another method of determining the amount of sizing present is that of washing a sample of the material thoroughly and comparing it with the original.

If material is to give good service, the warp and weft threads must be in good proportion. Materials having some heavy threads, as dimities, or having a much heavier warp than weft are apt to split owing to the unequal tension. Materials which have been on the market for some time may have become weakened by the action of the chemicals which were used in the bleaching or in the sizing.

The strength may be judged by the following test : Place the thumbs together and press them down hard on the material, holding the cloth tight underneath. Consider the amount of strain resisted.

In choosing between two grades of the same type of material, consider the additional wearing qualities obtained for a slight additional cost. Often a piece of material costing two or three cents more will wear twice or three times as long as the cheaper material. This is not always true, however, as sometimes a large part of the price is represented in the novelty of weave, design, or color. Obtain three sets of samples of different types of cotton materials which illustrate the above, and study them carefully.

The firmness of the weave and the quality of the fiber are always important factors to consider. To judge the quality of fiber, untwist a thread of the cloth and notice the length of the separate fibers. A long fiber indicates strength and, therefore, good wearing qualities, other things being equal.