Silk
A protein fibre like wool, and subject to the same alkali, enzyme and bleach restrictions — but no silk-specific fabric-care authority confirms them.
What not to do
Best avoided
The available guidance advises against this.
The failure modes are listed rather than implied: shrinkage, fading, dye bleeding, loss of shape, and a limp or rough texture.
Evidence
Supported
Sources
Drycleaning & Laundry Institute International (DLI) · Trade or professional body
Relied on for: That silk is highly sensitive to moisture, that washing it at home can cause shrinkage, fading, dye bleeding, loss of shape and a limp or rough texture, and that silk generally responds best to professional drycleaning. (states this directly)
Precautions
- Check the manufacturer's instructions
- Test on an inconspicuous area first
In detail
Silk is a protein fibre, built from fibroin rather than the keratin of wool, and it shares the chemistry that governs wool care: proteins are hydrolysed by alkali, cut by protease enzymes, and attacked by oxidising bleaches. On that basis the same restrictions apply — a mild neutral detergent rather than a biological one, no bleach, and gentle handling. That is an inference from protein chemistry rather than a silk-specific instruction, because no silk-specific fabric-care authority addresses it. What can be said with authority is where the answer lives. The body that devised the care-labelling system states that a garment's symbols indicate the MAXIMUM SEVERITY of treatment it can withstand without irreversible damage — so on silk the label is not a suggestion to weigh against general fibre advice, it is the specification, issued for that made-up garment including its dyes and finishes. Silk also differs from wool in ways the shared chemistry does not cover: it lacks wool's scale structure and so does not felt, and water spotting on some finishes has no analogue in wool care. Where the label specifies professional textile care, that is the answer.
Properties
Sensitivity
- Alkalis
- Not known
- Chlorine bleach
- Not known
- Heat
- Not known
- Abrasion
- Not known
- Porous
- Not known
“Not known” means nobody has established this, not that the material is unaffected.
Why
- Silk is explained by Dye migration and colour bleeding
- Silk is explained by Fibre swelling and shrinkage
- Silk is explained by Keratin digestion
Related
- Silk is commonly affected by Perspiration
- Silk is commonly affected by Antiperspirant residue
- Silk is commonly affected by Keratinophilic fungi
- Silk is commonly affected by Frass and pest residue
Hacks and claims involving this
- Oxygen bleach is the wool-safe bleach Does not work
- Dry-clean-only labels are just the manufacturer being cautious Does not work
- Washing silk at home Disputed
- The care label allows oxygen bleach even when it bans chlorine Does not work
- The dots on a care label are just a rough guide Does not work
- A stain method that works on cotton works on anything Does not work
- Leaving a stain in the sun to fade it Plausible mechanism, untested in this application
Sources for this page
Sources
GINETEX Technical Booklet — international care labelling system
GINETEX, The International Association for Textile Care Labelling, 2018 · Standards body
Relied on for: That care symbols indicate the maximum severity of treatment a consumer can use without damaging the article, that the labelled processes are intended to avoid any irreversible damage, and that professional textile care is one of the five labelled treatment families. (states this directly)
Kirk-Othmer Encyclopedia of Chemical Technology
John Wiley & Sons · Reference work
Relied on for: That silk fibroin is a protein and that proteins are hydrolysed by alkali and by protease enzymes. (background and mechanism only)