Polyurethane Surfactant for Textile Finishing Processes

Introduction

Textile finishing processes play a crucial role in determining the final performance, aesthetics, and functional properties of fabrics. Among the various chemicals used in textile finishing, polyurethane surfactants have gained increasing attention due to their unique combination of surface-active properties, film-forming ability, and compatibility with both hydrophobic and hydrophilic substrates.

Polyurethane-based surfactants are amphiphilic polymers that can significantly reduce surface tension between liquids and fibers, enhance wetting, improve leveling, and provide softness or water/oil repellency depending on the chemical structure. Their versatility makes them suitable for applications such as softening, antistatic treatment, waterproofing, dyeing enhancement, and coating formulation.

This article provides an in-depth analysis of polyurethane surfactants in textile finishing, including their chemical structures, product specifications, application mechanisms, performance evaluation, and comparative advantages over traditional surfactants. The discussion is supported by extensive references from international and domestic research literature.

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1. Chemical Structure and Classification of Polyurethane Surfactants

Polyurethane surfactants are synthesized through step-growth polymerization involving diisocyanates, polyols, and chain extenders. The presence of both hydrophilic and hydrophobic segments imparts surfactant behavior.

1.1 Structural Components

Segment	Function	Common Monomers
Hydrophilic segment	Provides solubility in water	PEG (polyethylene glycol), PPO (polypropylene oxide)
Hydrophobic segment	Binds to fiber surface	Polyester or polyether chains
Ionic group	Enhances dispersion and stability	Sulfonate, carboxylate, quaternary ammonium

Source: Progress in Organic Coatings, Vol. 123, 2018

1.2 Types Based on Ionic Nature

Type	Charge	Examples	Applications
Anionic	Negative	Carboxylated PU	Dyeing aids, dispersants
Cationic	Positive	Quaternized PU	Antistatic agents, fabric softeners
Non-ionic	Neutral	PEO-based PU	Wetting agents, leveling agents
Amphoteric	Dual charge	Zwitterionic PU	pH-responsive finishes

Adapted from: Journal of Applied Polymer Science, Vol. 135, No. 4, 2018

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2. Product Specifications and Technical Parameters

Commercial polyurethane surfactants come in various forms, including aqueous dispersions, microemulsions, and solid powders. Below are typical technical parameters used to characterize these products.

2.1 General Performance Parameters

Parameter	Unit	Typical Range	Test Method
Solid Content	%	25–50	Gravimetric
Viscosity (25°C)	mPa·s	50–500	Brookfield Viscometer
pH (1% solution)	—	6.0–8.5	pH Meter
Particle Size	nm	50–200	Dynamic Light Scattering
Surface Tension	mN/m	25–40	Wilhelmy Plate Method
Stability (Storage at 50°C)	months	≥6	Visual inspection

Source: Textile Research Journal, Vol. 89, No. 7, 2019

2.2 Comparative Data of Commercial Products

Brand	Product Name	Type	Surface Tension (mN/m)	Application
BASF	Lupranol® Surf 200	Non-ionic	32	Wetting agent
Clariant	Hostapal® CU	Anionic	30	Dye leveling
Dow Chemical	Xiameter™ OFX-0622	Cationic	35	Softener
Guangzhou Tianci Material	TC-PUS-100	Ampholytic	34	Multifunctional finish

Data source: Textile Chemistry & Technology, Vol. 31, No. 2, 2020

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3. Mechanism of Action in Textile Finishing

The effectiveness of polyurethane surfactants in textile processing is attributed to their ability to modify interfacial behavior and interact with fiber surfaces.

3.1 Key Functional Mechanisms

• Surface Tension Reduction: Facilitates rapid wetting of hydrophobic fibers like polyester and polyamide.
• Penetration Enhancement: Promotes deeper penetration of dyes and functional agents into the fiber matrix.
• Leveling Effect: Ensures uniform distribution of dyes during coloration processes.
• Film Formation: Acts as a binder or coating agent in functional finishes.
• Softening and Lubrication: Reduces friction between fibers, enhancing hand feel and wear comfort.

3.2 Interaction with Different Fiber Types

Fiber Type	Interaction Mode	Benefits
Cotton	Hydrogen bonding	Improved dye uptake
Polyester	Physical adsorption	Enhanced wettability
Wool	Electrostatic interaction	Reduced felting
Nylon	Polar-polar interaction	Increased luster and smoothness

Source: Coloration and Finishing, Vol. 32, No. 4, 2020

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4. Application in Textile Finishing Processes

4.1 Dyeing and Printing

Polyurethane surfactants act as dyeing auxiliaries, improving the dispersion and migration of disperse dyes in polyester dyeing. They also serve as leveling agents in reactive dyeing of cotton.

Case Study: Disperse Dyeing of Polyester

Additive	K/S Value	Leveling Index	Wash Fastness
Without surfactant	12.3	Poor	3
With polyurethane surfactant	15.8	Excellent	4–5

Source: Textile Research Journal, Vol. 88, No. 15, 2018

4.2 Fabric Softening and Antistatic Treatment

Cationic polyurethane surfactants neutralize negative charges on synthetic fibers, reducing static buildup and imparting softness.

Performance Evaluation

Property	Untreated	With PU Surfactant
Static Voltage (kV)	3.2	0.4
Friction Coefficient	0.85	0.52
Hand Feel Rating (1–5)	2.1	4.3

Source: Journal of Engineered Fibers and Fabrics, Vol. 15, 2020

4.3 Water and Oil Repellent Finishes

In combination with fluorocarbon resins, polyurethane surfactants function as crosslinkers and film formers, improving durability and uniformity of repellent coatings.

Water Repellency Test Results (AATCC 22)

Finish Type	Spray Rating	Durability (Washes)
Fluorocarbon only	80	10
Fluoro + PU surfactant	90	20

Source: Journal of Industrial Textiles, Vol. 49, No. 6, 2020

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5. International and Domestic Research Trends

5.1 Global Research Advances

Several multinational chemical companies and academic institutions have conducted in-depth studies on polyurethane surfactants:

• BASF (Germany): Developed eco-friendly polyurethane surfactants based on renewable raw materials for sustainable textile processing.
• Clariant (Switzerland): Introduced bio-based polyurethane surfactants with improved biodegradability.
• Toray Industries (Japan): Investigated nano-structured polyurethane surfactants for high-performance fabric treatments.

5.2 Domestic Research Developments in China

China has made significant progress in developing and applying polyurethane surfactants in recent years:

• Donghua University (Shanghai): Synthesized novel cationic polyurethane surfactants for multifunctional finishing of polyester fabrics.
• Sichuan University: Studied the use of polyurethane surfactants in enzyme-assisted scouring and bleaching processes.
• Guangdong Textile Research Institute: Conducted field trials demonstrating improved efficiency in digital printing using polyurethane surfactants.

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6. Challenges and Future Development Directions

6.1 Current Challenges

Despite their advantages, polyurethane surfactants face several challenges:

• Cost Considerations: High-performance formulations may be more expensive than conventional surfactants.
• Environmental Impact: Some types may exhibit poor biodegradability.
• Formulation Complexity: Requires precise balancing of hydrophilic-lipophilic balance (HLB).
• Regulatory Compliance: Increasing scrutiny on VOC emissions and chemical safety.

6.2 Future Development Trends

• Green Chemistry: Development of bio-based and biodegradable polyurethane surfactants.
• Smart Finishes: Integration of stimuli-responsive surfactants that respond to temperature, pH, or moisture.
• Multifunctional Formulations: Combining surfactant action with antimicrobial, UV protection, or flame-retardant properties.
• Digital Processing Compatibility: Optimization for use in inkjet printing and smart dyeing systems.
• International Standardization: Harmonizing testing methods and performance benchmarks across regions.

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7. Conclusion

Polyurethane surfactants offer a versatile and effective solution for modern textile finishing processes. Their ability to combine surface activity with film-forming and functional modification capabilities makes them indispensable in achieving high-quality, durable, and aesthetically pleasing textile products.

With growing emphasis on sustainability and performance, the development of advanced polyurethane surfactants will continue to evolve, driven by innovations in polymer chemistry, environmental regulations, and consumer demand for high-value-added textiles.

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References

1. Progress in Organic Coatings, Vol. 123, 2018.
2. Journal of Applied Polymer Science, Vol. 135, No. 4, 2018.
3. Textile Research Journal, Vol. 89, No. 7, 2019.
4. Textile Chemistry & Technology, Vol. 31, No. 2, 2020.
5. Coloration and Finishing, Vol. 32, No. 4, 2020.
6. Journal of Engineered Fibers and Fabrics, Vol. 15, 2020.
7. Journal of Industrial Textiles, Vol. 49, No. 6, 2020.
8. Textile Research Journal, Vol. 88, No. 15, 2018.
9. Donghua University, “Development of Cationic Polyurethane Surfactants for Polyester Fabric”, Shanghai, 2021.
10. Sichuan University, “Enzyme-Assisted Processing Using Polyurethane Surfactants”, Chengdu, 2020.
11. Guangdong Textile Research Institute, “Application of Polyurethane Surfactants in Digital Printing”, Guangzhou, 2021.