Cotton, Nylon, Lycra Spandex and Allergies
By Donald F. Groce, Best Manufacturing Company
Don Groce is Director of Technical Services at Best Manufacturing, the makers of the N-Dex glove. This article appeared in the September 1996 issue of Latex Allergy News.
Cotton, nylon and lycra spandex textile fibers alone do not contain latex. However, finished products may contain latex which was added to these textiles.
Cotton: Cotton is a naturally occurring cellulose agricultural fiber. Cotton grows on a cotton plant. Just like in Gone With the Wind, you can still see cotton fields throughout the southern United States. In fact, there are several cotton fields very close to where I live in Georgia. Cotton is the predominant textile used worldwide to make today’s garments. Cotton is blended with other textiles and absorbs moisture for a more comfortable garment.
Are there things added to cotton garments that would cause problems for latex-sensitized individuals? Elastic yarns are made with a core of either natural rubber fibers or lycra spandex with cotton wrapped around it. Natural rubber latex has been used since the 1920s as the central core for other fibers. Rubber yarns are used in foundation garments, swimwear, surgical fabrics, elastic bandages, support hose, underwear, elastic yarns, shoe fabrics, tops of socks and hosiery.
Elastic waistbands are used in 100% cotton underwear and in the leg openings. Rubber is cheaper and sews easier than synthetic elastics. A well known manufacturer of cotton underwear knew about the problems latex allergy victims encounter. They freely admitted that their waistbands and leg openings contained latex rubberized elastic.
What about the new “wrinkle-resistant” 100% cotton garments? These garments are treated with a glyoxal resin which does not contain latex. As long as they do not have elasticized waistbands or leg openings, they should be safe.
What about silk screened slogan tee shirts and heat transfer designs or prints? The materials used in these processes are thermoplastic resins and plastisol inks. They are plastic and not rubber. These do not contain latex and closely resemble vinyl.
Synthetic Fibers: Synthetic man-made fibers such as nylon, polyester and lycra spandex are different from cotton. They do not come from agricultural sources. The same distinction is made between natural rubber latex gloves and synthetic “non-latex” nitrile gloves. Like nitrile gloves, synthetic polymer textiles are made from chemical reactions and do not grow on trees.
Nylon: Nylon is made from a chemical reaction. If you took organic chemistry in college, you may have made nylon fibers in the laboratory. Nylon fibers consist of long, synthetic polyamide chains.
Nylons are known for their strength, flexibility, toughness, elasticity, washability and ease of drying. Nylon is used for apparel such as stockings, lingerie, dresses, bathing suits, foundation garments and wash-and-wear linings. Nylon is also used to make floor coverings, tire cord, industrial and upholstery fabrics. It can even be extruded into some of the films used for packaging perishable foods.
Allergic Reactions to Nylon: There have been cases of dermatitis from nylon stockings. However, sensitization has been linked to chemicals used to inhibit bacterial growth and to azo and anthraquinone dyes used to dye the stockings brown. These dermatological reactions were not linked to the actual nylon fiber. Respiratory disease has been linked to the inhalation of wool, cotton and synthetic fiber dusts in industrial settings where these fibers are made, but not to the finished products.
Spandex: DuPont first introduced Spandex in 1958. That fiber is now called lycra or lycra spandex. Spandex is a synthetic fiber made of at least 85% polymer polyurethane.
Spandex is made from several chemicals that are known sensitizers. TDI and MDI are used as precursors of the polyurethane used to make spandex.
TDI is a toxic chemical which is proven to be carcinogenic. It is also a skin irritant and can cause severe dermatitis. MDI is toxic and known to be an allergic sensitizer.
Manufacturers of spandex products must use strict quality control procedures to ensure that no residual unreacted MDI or TDI is in the final product.
Spandex threads are lighter weight, but more durable and supple than conventional elastic threads. Spandex does not suffer deterioration from oxidation like the fine sizes of rubber thread, and is not damaged by body oils, perspiration, lotions, or detergents. Spandex is used in the following products: bras, lingerie straps, sock tops, support and control-top hosiery, medical products requiring elasticity, fitted sheets, upholstery, bathing suits, and webbing. Spandex is never used as 100% of any fabric construction.
How do you tell if a spandex garment contains latex? You get conflicting reports. According to one manufacturer, the more sheer a garment is, the less likely it will have latex. Latex threads make a much heavier garment and cannot be woven into the very fine sheer configurations that characterize spandex garments.
Waistbands are the most likely place to find latex thread. Sewn-in waistbands are more likely to contain latex threads than knitted-in waistbands. In contrast, another manufacturer says that you cannot tell whether a waistband is made from rubber yarn or spandex yarn.
Some makers of dancewear and hosiery say that they have moved completely away from latex. U.S. garment manufacturers say that cheaper brands of clothing which are made in other countries are more likely to contain latex since latex is cheaper than lycra spandex. Most manufacturers I surveyed say that lycra spandex products are moving away from latex, but not because of latex allergies. The reason for moving away from latex is that the newer technology makes all lycra spandex garments more durable.
Cases of dermatitis due to spandex have been traced to rubber or rubber processing chemicals added to spandex. The spandex polymer itself has not been proven to be a sensitizer.
One of the largest manufacturers of swimsuits was also aware of latex allergies and confirmed that rubber elastic is used in the leg openings and straps of its lycra spandex bathing suits. They have tried other materials, but no other material can be sewn as easily. Production costs go up when you cannot sew as fast. The demand for latex-free bathing suits is not yet great enough to justify changing to another type of elastic that does not sew as easily.
In surveying textile manufacturers, sometimes the information is vague, to say the least. Some textile manufacturers have heard of latex allergies. Some have not. Some immediately tell you that there is no latex in their products, but will not certify that statement in writing. That makes me suspicious. Some do not know what latex is.
Labeling is still the only way of knowing what is contained in a finished consumer product. The FDA proposal that will require mandatory labeling is a much needed reform for medical devices.
But what about consumer products? Current FTC rules say that a manufacturer does not have to list components of a garment if the ingredient comprises less than five percent of the total make up of the product. Less than five percent is still a lot of material if the material is an allergen.
Allergists have indicated that the concentration to which sensitized persons respond is as small as four molecules. Usually, a latex allergy victim is atopic with multiple allergies. When a reaction to a garment is strictly dermatological in nature, it is possible that individuals are reacting to a chemical dye or some other sensitizing component. This is yet another situation where victims of latex allergy must rely on manufacturers for product content information.
Unfortunately, some manufacturers in industries unrelated to healthcare do not comprehend the implications of latex allergy. Maybe someone should make an elastomeric yarn that contains nitrile.
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