Washing, colorfastness

Stilbene dyes ate classed as a subgroup of azo dyes having excellent colorfastness and typical direct dye wash fastness on cotton and ate arranged iato six categories by the Society of Dyers and Colourists (2), as described ia the foUowiag. 

Flax fabrics (linen) have an excellent hand, fair abrasion resistance, fair pilling resistance, good stability to repeated launderings, fair sunlight resistance, excellent colorfastness. veiy poor wash and wear performance, and poor wrinkle resistance. 

The physical and chemical properties of dyes are very important for even coloring. First a hair dye should have comparable affinities for the roots, damaged areas, and tips. Second, the combined yellow-to-blue dyes used for shading must have similar properties so that color shifts will not take place when the hair is washed, for example. The importance of these problems is illustrated by the number of patent applications disclosing new, custom-tailored dyes [35] and suitable dye mixtures [42], The relatively good colorfastness and stability of some nitro dyes allow them to be used in oxidation hair dyes as well, especially for the shading of brilliant (mainly red) fashion colors. 

Normally, the first step in textile conservation is the examination of the piece to determine the fibers from which it was made and the technique by which it was created. One determines the spin of the yarns, whether Z or S, and the number of wefts and warps per inch. Next, one tests for colorfastness first with distilled water, then with glycerin and water, and finally with a neutral detergent and water. If the colors run with any of these solutions, obviously the piece cannot be washed, and one tests with dry-cleaning solvents and other chemicals. 

Table II. Transfer of Color from Fabric to Multifiber Test Strip in Colorfastness to Washing and Colorfastness to Perspiration Tests (Evaluated Using Gray Scale for Staining)...

Color Reaction to Historic Cleaning Procedures. Another set of colorfastness tests was adapted primarily to simulate conditions under which the dress may have been cleaned. X-ray analysis indicated the presence of potassium and the higher levels of sulfur on the dress, as compared with the unused remnant. In the earlier X-ray analysis, the Kevex-ray detected some detergent residues on the washed specimen. It is possible that the elements detected on the dress could be residues from cleaning processes used earlier in this century, which might have been used to care for this dress. 

AATCC Test Method 61-75 "Colorfastness to Washing, Domestic and Laundering, Commercial Accelerated," and International Standard Method C06 were modified to establish the laundry procedure to simulate one home laundering cycle. An Atlas Launder-Ometer equipped with stainless steel canisters was used. Teflon liners were used In the lids to prevent retention of pesticides by the rubber gaskets. Abrasive action was provided by the placement of 25 steel balls In each canister. 

Cellulose acetate and triacetate can be spun-dyed. Spun-dyed acetate and triacetate yarns are extremely colorfast to washing, dry cleaning, sunlight, perspiration, sea water, and crocking and are very resistant to gas or fume fading [15]. 

Yuen and Kan (2007) studied fasmess to light, washing, and crocking of the digital inkjet-printed cotton fabrics with plasma pretreatment. The results showed that colorfastness of inkjet-printed cotton fabric with plasma pretreatment was better than the untreated cotton fabric. Of the different plasma treatment exposure limes studied, better maximum colorfastness was achieved at 2 and 5 min of plasma exposure... 

Colorfastness n. Resistance to fading i.e., the property of a dye to retain its color when the dyed (or printed) textile material is exposed to conditions or agents such as light, perspiration, atmospheric gases, or washing that can remove or destroy the color. A dye may be reasonably fast to one agent and only moderately fast to another. Degree of fastness of color is tested by standard procedures. Textile materials often must meet certain fastness specifications for a particular use. 

A garment that isn t colorfast may bleed its dye in the wash and stain other clothing. Luckily, it s easy to test colorfastness before washing. Simply soak the fabric in soapy (room temperature) water, and, after a half-hour or so, take it out and check for dye in the water. Set your garment on paper towels to dry. If no dye bleeds into the water or onto the towels, your garment is colorfast. 

Consider and test the detaiiing. Some care instructions are for the fabric only—not the embellishments or hardware, which may be attached at another factory. This is why some labels come with caveats, such as exclusive of decorative trim. Before attempting to wash items featuring beads, sequins, fringe, or tassels, make sure they are sewn on (not glued) and colorfast. 

In particular, tests regarding surface changes after applying a load and colorfastness tests after washing are of special interest. In addition, handle and drapeability are often considered. 

---