A Comprehensive Analysis of the Four Key Parameters of Amino Silicones and Their Impact on Application

Amino silicones are an important component of textile finishing agents, and their quality directly affects the performance and style of fabrics. Below is an in-depth analysis of four key parameters—ammonia value, viscosity, reactivity, and microemulsion particle size—along with their effects on the characteristics and application of amino silicones.

1. Ammonia Value: The Core Indicator for Softness and Emulsification Performance

The ammonia value refers to the volume (in milliliters) of 1 equivalent molar concentration of hydrochloric acid required to neutralize 1 gram of amino silicone, which directly reflects the amino content.

• Softness and Smoothness Enhancement: The higher the ammonia value, the higher the amino content, resulting in softer and smoother fabric after finishing. This is due to the increased affinity of the amino groups, leading to more regular molecular arrangement.
• Risk of Yellowing: The active hydrogen in amino groups is prone to oxidation, forming chromophores that can cause yellowing of fabrics. The higher the ammonia value, the greater the likelihood of oxidation and yellowing.
• Emulsification Performance: A higher ammonia value increases molecular polarity, facilitating the preparation of microemulsions, while optimizing emulsifier selection and particle size distribution.

2. Viscosity: The Key to Balancing Feel and Penetration

Viscosity is related to the molecular weight and molecular distribution of amino silicones, directly affecting fabric performance:

• Advantages of High Viscosity: Higher viscosity results in better film-forming properties, providing fabrics with a softer, smoother feel. However, its penetration is reduced, especially in densely woven fabrics.
• Advantages of Low Viscosity: Lower viscosity improves penetration, and through the addition of crosslinking agents or process optimization, both softness and smoothness can be achieved.
• Viscosity Balance: It is necessary to adjust viscosity in combination with ammonia value to meet the specific requirements of different fabrics.

3. Reactivity: A Key Factor in Improving Elasticity and Fullness

Amino silicones have crosslinking reactivity:

• Enhancing Finishing Effect: Self-crosslinking during finishing or by increasing curing conditions can enhance fabric smoothness, softness, and elasticity, with especially significant improvements in elasticity for stretch fabrics.
• Optimizing End-Group Design: The higher the ammonia value, the better the crosslinking degree, which in turn improves fabric elasticity.

4. Microemulsion Particle Size and Charge: Determining Stability and Processing Effectiveness

• Impact of Particle Size: Small particle sizes (typically <0.15μm) improve dispersion, penetration, and uniformity, while enhancing storage and heat stability.
• Charge Selection: Cationic emulsions are more easily absorbed by anionic fibers, improving the treatment effect; non-ionic emulsions are generally better for uniformity compared to anionic emulsions.

Conclusion: The Art of Balancing Amino Silicone Performance Optimization

The four key parameters—ammonia value, viscosity, reactivity, and particle size—of amino silicones are interrelated and determine the final fabric performance, including touch, gloss, and elasticity. By adjusting these parameters according to specific process requirements, optimal treatment results can be achieved, providing fabrics with superior texture and functionality.