Silk continues to be a troublesome fabric for many drycleaners. Independent Garment Analysis Service receives many silk garments ranging from color loss due to oxidation and spotting procedures. The dye choice of the manufacturer and its application determines the fastness of the dye. Poorly dyed silk fabrics can still be processed but the inspections, spotting and cleaning methods must be changed.
If you go into a retail store and examine silk garments on the rack it will enlighten you to the extent that fading can occur. Just compare unexposed areas to exposed areas such as on the shoulder. The same inspection should be done at the counter. Examine for discolorations on the underarm area as well as weak areas. Silk fabrics are highly sensitive to chloride salts found in deodorants and perspiration.
SAFE SPOTTING TECHNIQUES
Always place an absorbent towel under the fabric when flushing with the steam gun. This will prevent dye transfer and indicate the stability of the dye to water and wetside agents. If you flush into a screened area the wet area of the silk will not indicate dye loss until it is dry. If dye transfer occurs readily the method of stain removal must be modified.
If dyes are stable to flushing, the garment is placed on a towel and a neutral lubricate is applied. Tamp area with a soft spotting brush and note stability of dye.
If dyes are determined to be weak the safest spotting agent available is a powdered enzyme. This is good for protein and albuminous stains as well as some tannin stains. Alkali in protein formulas will bleed dyes on silk. Liquid enzymes have lubricants in their composition and require extensive flushing which is not quite as safe. To use powdered enzymes put ½ teaspoon of digester in a pint of warm water (100-120oF). Add a teaspoon of glycerin or neutral lubricant for better penetration and also keep the area wet. Place this mixture on stained area for 20 minutes before flushing. This method is considered to be as safe as just applying plain water.
- TANNIN STAINS
Most tannin formulas are safe to dyes on silk. If the lubrication tends to bleed the dye when mechanical action is applied use a chemical action of the tannin formula. Apply to stain and heat with a steam gun and then flush. Acetic acid can also be used for chemical action. Test oxalic and rust remover which are generally safe to the dyes on silk.
- PROTEIN AND ALBUMINOUS STAINS
Refer to the section on digesters.
Last traces of staining can usually be removed with a mild hydrogen peroxide. This is the only neutral based bleach available. Sodium perborate and sodium percarbonate are alkaline in nature and will discolor silk dyes. Although testing is required before using peroxide it is generally safe. Apply hydrogen peroxide with a q-tip and allow it to be exposed to the air for 20 minutes. Then flush and repeat the method if it has been showing results.
Many cleaners are adept at feathering by flushing the area and forced drying the wet area from the outside toward the center. The only problem with this method is that the forced drying can remove dye from the silk garment as well as chafing the yarns. I would rather use the method of steaming the outside area of the ring and wiping the wet area with a towel so it blends into the dry area. This is the safest and most efficient way of feathering a silk fabric.
- LEVELING AGENTS
Difficult feathering can be avoided by applying a leveling agent. It is also interesting to note that Cleaners Chemical Corp has a tannin and enzyme based protein formula with a built in leveling agent. This means that after spotting the area can be feathered or just hung to dry and then recleaned.
- DRYSIDE STAINS
I would rather use a mild oily type paint remover then a strong one. You can judge the strength by the color of the paint remover. The light colored paint removers are mild while the darker ones are stronger. The problem with oily type paint remover is that water present in the paint remover will activate the alcohol that is present in its composition causing color loss. Oily type paint remover should also be used with amyl acetate which aids in dryside stain removal as well as diluting the strength.
DRYCLEANING POORLY DYED SILK
The routine drycleaning process should not affect dyes on silk. If moisture is present the dyes will bleed and discolor. The problem I have observed in my consultations is that a small load of silk is subjected to the same amount of soap injection as a large load. Detergent is injected based on the amount of solvent in the wheel rather than garment weight. Batch injection detergents contain a great deal of moisture and small silk loads subjected to the moisture can bleed and discolor.