Hydroxypropyl beta-cyclodextrin: Ushering in the era of "molecular keys" for textile dyeing and finishing

Hydroxypropyl beta-cyclodextrin ( Hydroxypropyl- β -Cyclodextrin, HP- β -CD ) is a hydroxypropyl derivative of β - cyclodextrin (β -CD ), which significantly improves the water solubility, inclusion capacity, and biocompatibility of β -CD through the introduction of hydroxypropyl substituents. Its application in textile printing and finishing not only inherits the unique properties of cyclodextrin but also expands its functional range due to improved properties after modification. The following is HP- β -CD a specific application and technical analysis:

I. HP- β -CD Characteristic Advantages

1.  Enhanced Water Solubility: Hydroxypropyl substituents break the intermolecular hydrogen bonds of β -CD molecules, significantly increasing their solubility in water (up to 50% or more), making them easier to disperse in printing and dyeing processing liquids.

2.  Optimized Inclusion Capacity: The hydrophobic cavity size ( 0.78 nm ) is similar to β -CD ，but the hydrophilic surface is more likely to form stable inclusion complexes with polar molecules (such as dyes and drugs).

3.  Low Toxicity and Safety: High biocompatibility, suitable for medical textiles and fabrics in direct contact with the skin.

4.  Improved Thermal Stability: Suitable for high-temperature dyeing or finishing processes (such as polyester high-temperature and high-pressure dyeing).

II. Application in Textile Printing and Dyeing

1.  Dye Solubilization and Dispersion

   -  Hydrophobic Dye Dispersion: HP- β -CD It can efficiently encapsulate and disperse hydrophobic dyes such as disperse dyes and acid dyes, reducing dye aggregation and improving dyeing uniformity. For example, in polyester disperse dye dyeing, adding HP- β -CD can lower the dyeing temperature (from 130 ℃ to 110 ℃), saving energy.

   -  Natural Dye Enhancement: It significantly enhances the solubilization of plant dyes (such as indigo and curcumin), improving the depth and fastness of natural dyes.

2.  Improved Color Fastness

   -  Enhanced Dye Fixation: By encapsulating dye molecules, it reduces the hydrolysis or shedding of unfixed dyes, improving wet rub fastness (improving 0.5-1 grade).

   -  Wastewater Reduction: Adsorption of residual dyes, reducing the COD value of dyeing wastewater, meeting environmental protection requirements.

3.  Functionalized Dyeing Processes

   - Simultaneous Dyeing of Multiple Components: Utilizing HP- β -CD the selective inclusion of different dyes to achieve simultaneous dyeing of multiple dyes (such as the mixed use of reactive dyes and disperse dyes), simplifying the process flow.

   -  Smart Responsive Dyeing: Combining thermosensitive / photosensitive molecules (such as spiro pyran) to develop color-changing textiles.

III. Application in Textile Finishing Agents

1.  Long-lasting Slow-release Functional Finishing

   -  Antibacterial Finishing: Encapsulating antibacterial agents such as silver nanoparticles and quaternary ammonium salts, prolonging the antibacterial effect through slow release (such as cotton fabric after HP- β -CD/ chitosan composite finishing, the antibacterial rate against E. coli >90% ).

   -  Fragrant Finishing: Loading essential oils (such as tea tree oil and peppermint oil), HP- β -CD the strong inclusion ability can prolong the fragrance retention time to 30 washings or more.

   -  Drug Slow Release: Encapsulating anti-inflammatory drugs (such as ibuprofen) in medical dressings for release triggered by body fluids or friction.

2.  Flame Retardant and Anti-UV Synergy

   -  Flame Retardant Enhancement: Encapsulating phosphorus - nitrogen flame retardants, reducing flame retardant migration and improving thermal stability (such as polyester fabrics after flame-retardant finishing LOI value increased to 28% ).

   -  Anti-UV Durability: Encapsulating benzotriazole UV absorbers, enhancing the binding with fibers through hydrogen bonds, and improving the washability 50%。

3.  Self-cleaning and Stain Removal

   -  Oil Stain Adsorption: HP- β -CD The treated fabric can adsorb oil and sweat stains, releasing the stains during washing, suitable for sportswear or tablecloths.

   -  Photocatalytic Synergy: With TiO ₂ or ZnO nanoparticles composite, improving photocatalytic decomposition efficiency by encapsulating pollutants.