NEW FABRICS

New Zealand Journal of Agriculture, Volume 92, Issue 1, 16 January 1956, Page 89

NEW FABRICS

By

DAPHNE EILERS,

Field Officer in Rural Sociology, Department of Agriculture, Auckland DURING this century science has travelled far in the production of synthetic fibres. From such materials as wood chips, milk, peanuts, and coal, fibres have been produced by way of the test tube. In a world where population is ever increasing synthetic fibres assume great importance both alone and combined with natural fibres.

'T'WENTY years ago the consumer could buy a fabric knowing by its appearance and handle from which fibre it was made and what performance could be expected from it. Today there is such a bewildering array of new and strange fibres in a variety of textures and blends that a casual knowledge is not enough. The factors affecting the housewife’s choice are not bound merely by the colour and texture and apparent suitability of the cloth. She wants to know the answers to such questions as “Will it wash or must it be dry cleaned?”, “How does it react to ironing?”, “Will it burn readily?”. Sometimes it is difficult to get answers to these questions, as the actual fibre content is not always known. In some countries it is the practice to have a fibre content label and a label with cleaning instructions attached to material lengths and to ready-made goods. This makes the choosing of cloth for various purposes very much simpler for the buyer. However, until this becomes a general practice in this country the buyer

must use her own knowledge to help her in her choice. Types of Fibres The four material fibres which have been the most important for cloth construction are wool, silk, cotton, and linen. 'Until the beginning of the 20th century natural fibres had no rivals, but in 1900 work was begun on the first man-made fibre, rayon. In the past 50 years vast improvements have been made to this fibre and today there are three types of rayon on the market, viscose, bemberg, and . cellulose acetate. A second type of man-made fibre has been ' developed during recent years—the regenerated protein fibres. Of these the three important ones are the fibres from peanut protein, from the casein in milk, and from maize. None of these, however, is used alone. They are important because they blend easily with other fibres and though not strong enough for use alone, do not lessen the desirable pro-

perties of the fibres with which they are blended. In this way natural fibres are conserved by blending. True Synthetic Fibres The third type of man-made fibres are the true synthetics. Often people are heard to name any man-made fibre a synthetic. This is not so. Rayons and regenerated proteins are produced chemically from natural products (wood chips, cotton waste, and protein substances) ; their actual molecular structure is re-arranged. True synthetics are synthesised from such things as oil, coal, air, and water. Their molecular structure is built up chemically. Of these synthetics nylon is probably the best known, though within the last few years many more have reached New Zealand markets either as ready-made goods or in the bolt. Terylene (American counterpart is dacron), perlon (French nylon), orlon, and dynel are all procurable. Saran is another synthetic whose main use is for car upholstery, as it is said to be practically indestructible. These man-made fibres are produced as long threads known as continuous filaments. A number of these continuous filaments may then be twisted together to produce a multi-filament yarn or, if they are sufficiently. thick, they may be used singly as monofilament yarn. Fabrics made from continuous filament yarn are usually

sheer, light in weight, and have a crisp drape. Alternatively, the filaments can be cut into lengths to produce “staple fibre”. These lengths are determined by the use to which they are to be put. If the resultant fabric is to simulate a worsted material, the staple will be long; if the appearance of a woollen cloth is wanted, the staple will be short. In some cases the staples will be crimped in imitation of the natural crimp of wool. The staple fibre is then spun into yarn in the same way as wool is spun. It is from this particular process that such names as spun rayon, staple fibre orlon, and staple fibre dynel are derived. The skill of the manufacturer in producing cloths from these man-made fibres is such that it is often difficult to tell from the handling or appearance from what fibre the fabric is made. There are, however, a number of simple tests by which the housewife can determine the fibres present. To make these tests it is necessary to obtain a small sample of the cloth, as obviously it would not be practicable or looked on with much enthusiasm by the retailer should, the housewife start experimenting in the shop. Warp and weft threads drawn from the sample should be tested, also any yarn forming a contrast in pattern or design, as these may not be of the same fibre as the body of the cloth.

Identification Tests Tensile Strength To test the strength of the fibre a short length of yarn should be held firmly between the thumb and forefinger of each hand and given a sharp tug. This is repeated with a moistened yarn. If there is a considerable loss of strength when the yarn is wet it can be assumed that it is rayon. If there is no appreciable difference, the yarn is likely to be wool, silk, or one of the synthetics. Should ' the yarn show an increase of strength when wet, it will be cotton or linen. Burning Test For the burning test the yarn should be held to a flame and then removed. A lighted candle is most satisfactory for this. The smell of the burning yarn, the type of ash or residue, and whether the yarn burns both in ' and out of the flame will all help in identifying the fibre content. Wool, silk, and 'protein fibres burnin the flame, giving off a strong smell of burning feathers. A black bead is formed which is readily crushed between the fingers.

Cotton, linen, and some rayons burn both in and out of the flame. They have a smell like burning paper and leave a wispy grey ash.

Acetate rayon burns in and out of the flame, giving off a smell of acetic acid and leaving a hard, shiny black bead. This bead is uncrushable when pressed between finger and thumb.

Nylon melts and shrinks away from the heat of the flame. A faint white smoke is discernible and a hard, light coloured bead is left. ' Terylene has a reaction similar to that of nylon, but can be distinguished from it by . the sooty smoke it gives' off. Orlon burns both in and out of the flame and leaves a hard black bead similar to that left by acetate rayon, but there is no accompanying smell of acetic acid, so that the two fibres could not be confused. Testing of Blends '.-Trouble may be experienced where there is a blend of two or more fibres in . the yarn.. For example, with a blend of wool and nylon there will be a smell of burning feathers and a fairly hard black bead will be left. The mixture will not burn out of the flame. By burning alone it would not be possible to tell whether the second fibre was acetate rayon or nylon. However, by comparison of tensile strength wet and dry this fact would be established, since the yarn would be weaker when wet if it contained rayon. If nylon was present, there would be little or no difference in strength between the wet and dry yarn.

A wool-cotton blend after burning will leave a black ash with a . small amount of white. If there is a greater amount of cotton than wool, the ash will be. grey and will hold the shape of the original piece of yarn. There is no simple way by which the housewife can determine the actual proportions of fibres in the blend. • Testing for Washability and Dry Cleaning When the type of fibres present in the material is known attention should be given to the effect of washing or of dry cleaning fluids on the cloth. Where the material is made from only one type of fibre this may not be necessary, as the housewife will probably know from past experience. If the cloth has a mixture of fibres in it. however, it is advisable to test small pieces in soap and water and in dry cleaning fluid to note the reaction. Difficulty is sometimes experienced in ironing materials which have a warp of one fibre and another fibre as a filling thread. If one has a very much lower melting point than the other, puckering will occur should the iron be too warm for one fibre. If the' prospective buyer -discovers this from

the test made on the sample, she would be wise to avoid that material and choose one which will not raise the problem. If it is a crease-resistant fabric, of course, ironing will not be necessary, so the difference in melting point of the two fibres will not affect the buyer’s choice. Properties of Textile Fibres While no one fibre, natural or manmade, has every desirable property, each is suitable in its own field. Most people are well aware of the properties and uses of all the natural fibres. Through the years the public have come to know just what can be expected from rayon materials and what treatment best suits them, but the properties of the synthetics are not so widely known. Many people look on them as “wonder” fabrics and in many ways they are, but like other fibres they have some properties which are not desirable. It is well for the buyer to realise their limitations before purchasing them.

The synthetics have a very high tensile strength both wet and dry, so they are excellent for sheer fabrics, but materials made from the staple fibre form are inclined to form hard pills on the surface which are difficult to remove. Synthetics are resistant to rubbing and for this reason will wear longer. Stockings made from nylon will rarely wear out at heels and toes. The usual cause of loss is through pulls and snags on sharp edges. Terylene stockings are now on the market and there seems to be little difference between them and nylon ones except that they are a little harsher to the touch.

Crease resistance is an important property of the synthetics. It makes them particularly useful for travelling, as superficial creases caused by packing will quickly fall out when the garments are hung in the air for a short time.

They also have a very low moisture absorption, which is the reason for their rapid drying. Once again this is of great advantage to the traveller. Conversely, their low moisture absorption is one of their disadvantages. They do not absorb perspiration to any degree, so there is risk of chilling with sudden temperature change. This lack of absorption is more pronounced with garments made in a plain weave from continuous filament yarn and these may prove most uncomfortable to wear in hot, humid weather. Undergarments to be worn next to the skin cause less discomfort if they are of a mesh weave. Synthetic materials made from staple fibre yarn appear to have greater absorptive properties. Pleats in synthetics are not affected by washing or by rain, but again to offset, this advantage of poor absorption there is the possibility of rain passing right through the fabric.

Synthetic fabrics are “heat set” during manufacture to prevent shrinkage on washing. Pleats and creases are also “heat set” for permanence. If an iron of higher temperature than that of the “heat setting” process is used on the synthetic fabric, further shrinkage may take place. It is unlikely that this would be done other than accidentally, but it is a possibility. Great care should be taken to use only a warm iron. If difficulty is experienced in achieving a flat, pressed look when ironing filament nylon, it will be found that repeated light use of low heat and a damp cloth will give the best results.

White synthetic fabrics are likely to discolour, as the fibres will absorb small quantities of oil and grease from the skin. They also take up traces of dye shed by other garments if they are washed with coloured garments. For this reason synthetics should always be washed separately and as soon after use as possible. One great advantage of the synthetics is their resistance to mildew and to insects. As they are chemical fibres, they contain no nutriments for moths or other pests. Storage of synthetic garments thus presents no hazards. All are resistant to chemicals with the exception of nylon, which is affected

by acids, and terylene, which is not as resistant to alkalis as are the other synthetics. Fibre Blends The main purpose of blending fibres is to achieve fabrics with the desirable properties of the fibres while minimising the undesirable properties. This blending of fibres may - be achieved in two ways. For example, in a wool-nylon blend the nylon may be a long, continuous filament with the wool spun round this nylon core. Alternatively, the nylon may be cut into staples and blended thoroughly with the wool fibres. The mixture is then spun into yarn. The method used will depend on which property is to be emphasised. In a nylon-wool blend where emphasis is to be on durability a blend in the staple would give best results. If a . crisp drape and quick drying were more important (as in a cotton-nylon frocking material), the filament core of nylon with cotton fibre spun round it would be suitable. In blends of synthetic fibres with natural fibres the synthetics contribute strength, resistance to rubbing, and quick drying and help to reduce shrinkage. Blending of a synthetic

and wool is useful in the production of permanent pleats in skirts and in permanent creases in trousers. The natural fibres contribute softness, warmth, moisture absorption, and in some cases cheapness. Rayon is important, too, in blends for its cheapness and moisture absorption. There are many wool and rayon mixtures on the market today. Usually they are labelled as “wool and fibro” materials. . Much work is being done on these blends, and tests for fabric strengths, abrasion resistance, crease resistance, and effects of dry cleaning and laundering, as well as many others are made to determine the effects of altering the proportions of different fibres in blends. It has been found that 75 per cent, dacron combined with rayon gave the resultant fabric resilience comparable to all wool, while only 25 per cent, dacron was needed in a dacron-rayon mixture to add crease-resisting properties to the rayon. Nylon was effective in increasing abrasion resistance and orlon improved the stability of wool, acetate rayon, and rayon fabrics to dry cleaning and laundering (J. B. Quig and R. W. Dennison, “Textile Research Journal” 24, No. 4, April 1954, p. 361).

The addition of synthetics to wool appears to reduce felting or shrinkage sometimes resulting from washing. Interesting colour combinations can be effected with these blends. Where one fibre of the blend will “take” a certain dye, the other may not, so that, a mottled effect can be achieved. Shot effects can now be given to rayon materials by having one set of threads of acetate rayon and the other of viscose. The material “in the grey” is run through a dye bath where the acetate is dyed the desired colour and the viscose is. unaffected. When the material is placed in a second dye bath containing dye of another colour the viscose rayon is then tinted. A shot effect previously could be made only by dyeing the yarn before the loom was threaded up. The warp threads would be of one colour and the filling or weft threads of another. Man-made fibres appear to have found their place in the textile world and instead of presenting a threat to the natural fibres they may prove even more useful in the future in augmenting the supply, of natural fibres and reducing the cost of materials.

Care of Patent Leather Shoes PATENT leather is produced by coatings of boiled linseed oil being poured on to a foundation of leather, the whole then being baked in stoves at a moderate heat. Since this treatment alters the porous nature of the leather and deprives it of some of its elasticity, shoes of this material are less comfortable to wear, than those of other leathers. A cheaper variety of patent leather is sometimes made from ■ a foundation of canvas coated with a black preparation and then varnished. Patent leather shoes should be cleaned in the following way: — Dust them thoroughly and if necessary wipe them with a damp cloth, using mild soap. Apply shoe polish with a small piece of soft cloth and . rub the polish in thoroughly. Polish them with a duster and finish off with a velvet pad, or ' Use petroleum jelly ,or olive oil instead of shoe polish; these help to keep the leather soft and pliable. Shoes should always be allowed to dry thoroughly at room temperature and be well aired after each wearing. Shoe trees should be used to keep them in shape. It is preferable for shoes to be kept in a shoe rack or on a shelf rather than in a closed cupboard. These measures will prolong the life of any shoes.

—MAUD B. STRAIN,

Field Officer in Rural Sociology, Department of Agriculture, Dunedin