2—PERMANENT-PRESS EFFECTS IN WOOL: PART V: METHODS OF STABILIZING SET

Abstract

Shrink-resist wool set in the normal way can lose wanted set or acquire unwanted set during machine-washing and tumble-drying because the molecular-bond rearrangements responsible for setting can still occur during the laundering cycle. The set can be stabilized to withstand such laundering by any of the following methods:

1. the inhibition of thiol-disulphide interchange by:

   1. removing ionized thiol groups, or

   2. converting disulphide bonds to non-interchangeable links, such as —S—, —SCH₂S—;

2. the introduction of new cross-links; or

3. denaturation to form structures that are slow to rearrange during washing.

The stability of set is enhanced by a combination of the methods because these operate by different mechanisms. Prevention of thiol-disulphide interchange appears to be more important during washing, whereas the presence of cross-links appears to be more important to aid recovery during tumble-drying.

KEY WORDS (SPECIFIC TERMS):

• SET
• PERMANENT SET
• DURABLE-PRESS
• STABILIZATION
• STATIC RELEASE
• OXIDATION
• DENATURATION
• BLOCKING
• STEAMING
• SOAKING
• HEATING
• MACHINE-WASHING
• TUMBLE-DRYING
• SHRINKPROOFING
• CROSS-LINKING
• SELF-CROSS-LINKING
• DISULPHIDE INTERCHANGE
• WET SETTING
• DRY SETTING
• COLD SETTING (EXCEPT SYNTHETICS)
• HIGH-TEMPERATURE SETTING
• CROSSBRED WOOL
• WORSTED FABRICS
• FORMALDEHYDE
• METHYLOL-NYLONS
• SODIUM BISULPHITE
• SODIUM PERBORATE
• APO
• DISULPHIDE BONDS
• THIOL GROUPS
• WASHING MACHINES

KEY WORDS (BROADER TERMS):

• STRESS–STRAIN PROPERTIES (TENSILE)
• FINISH (PROPERTY)
• REACTIONS (CHEMICAL)
• WET FINISHING
• LAUNDERING
• DRYING
• SETTING (EXCEPT SYNTHETICS)
• WOOL
• WOOL FABRICS
• FABRICS (ACCORDING TO FIBRE)
• METHYLOL COMPOUNDS
• POLYMERS
• CHEMICAL BONDS