Silk fabrics are characterized by a unique feel, luster, body, hand and sheen. These characteristics are imparted by the manufacturer when producing silk. The successful wetcleaning process maintains these inherent properties. When drycleaners immerse silk in water and the fabric comes out stiff, lusterless and wrinkled they are not using proper wetcleaning techniques.
IDENTIFICATION
Many drycleaners who are adept at fabrics can determine silk from polyester by feel. You can also distinguish silk from polyester by wetting a small area and squeezing it in attempts to wrinkle. Silk will wrinkle easily while polyester will not. A burn test is a positive identification of silk. Cut a small sample from an unexposed area. Apply a lit match to the sample. Silk will sizzle, smell like burning hair and leave a bead that can be crushed. Polyester will simply melt and leave a bead that cannot be crushed.
POTENTIAL DYE PROBLEMS
You can check dye fastness by flushing the silk with a steam gun over a clean white towel. Note how readily the dye bleeds. A small amount of dye transfer does not designate a poor dye.
SHRINKAGE
Silk that contains twisted yarns such as crepe and matte jersey are potential shrinkage problems. You can put the hemline of the silk on a spotting board and spray with water, noting whether the fabric shrinks.
DISTORTION
Silk velvets will distort in the wetcleaning process and should not be wetcleaned.
PRESPOTTING
Use a soft brush or padded brush for mechanical action. When brushing with a bristle brush angle the brush so the outside edge contacts the fabric.
- Soil: Avoid spray spotters since they are usually anionic in nature. This means that they will break down and form rings when in contact with a cationic detergent used for wetcleaning. Manufacturers are now producing nonionic lubricants which are compatible with all detergents.
- Tannin stains: Tannin formulas can usually be used safely but need to be flushed thoroughly before wetcleaning to avoid detergent breakdown.
- Protein formulas: They are usually low in alkalinity and are usually safe for silk. They also must be flushed thoroughly before wetcleaning.
WTCLEANING PROCESS FOR SILKS
Many detergent manufacturers advocate using anionic detergents and fabric softeners for silks. In my experience the best detergent for silk should be a cationic detergent. These detergents tend to stay with the fabric providing better softness and dye stability. Wetclean the silks using cationic detergent on a gentle machine cycle or wetcleaning equipment programmed for silk. Do not allow the silks to soak in the washer as this promotes dye transfer. It must be kept moving in the machine at all times. The next cycle is rinse cycle with a prescribed amount of fabric softener. The fabric softener used should be cationic in nature which are compatible with the cationic detergents. After rinsing the fabric is extracted, ready for drying.
DRYING
Dry in a dryer at 120℉ or in a moisture controlled dryer. The silk fabric should come out 90% dry. This means that the fabric is dry but the seams are slightly wet. In a regular dryer it may take anywhere from 12 to 18 minutes to dry.
BLEACHING SILK FOR WHITENING
- Soak white silks in sodium perborate or sodium percarbonate. Use approximately 2 ounces per gallon of water. Add a nonionic detergent to help penetration of the bleach and maintain softness to the fabric. Rinse fabric and then neutralize with acetic acid (2 ounces per gallon of water). Rinse again in water with a fabric softener.
- White silks can also be soaked in sodium hydrosulphite and a nonionic detergent for 15 minutes. Use 2 ounces per gallon of water. Rinse again with a fabric softener.
