How Does Silicone Emulsion Enhance the Durability of Textile Materials?

Extending the service life of textiles requires an understanding of the molecular phenomena at play. When a textile is treated with a siloxane polymer, the molecular structure of the polymer and the siloxane enable the polymer to form a protective barrier around each individual fiber. Additionally, the siloxane polymers have flexible organic “side chains” that act like miniature springs, absorbing the energy of the mechanical stress when the fabric is bent or stretched. In contrast, traditional fabric treatments are hard and stiff which leads to increased localized stresses. These localized stresses create a focus of mechanical energy that leads to more rapid failure of the fabric. Siloxane coating treatments are able to redistribute stresses more evenly throughout the entire reinforced area which allows the fabric to withstand substantially more stretches and bends without losing its original mechanical properties.

The Reduction of Surface Energy and Interfiber Lubrication Minimize Damage Caused by Friction

Silicone microemulsions used on fabrics have shown to decrease surface energy to less than 30 mN/m compared to ~70 mN/m for untreated cotton. This makes them super water repellent; during a rain event or a splash the water beads and rolls off the surface rather than wetting the fabric. The PDMS component in these treatments also performs in a fantastic way between fibers. It serves as a lubricant and reduces the friction between threads by 50%. This means that during the wear of the garment when fabrics rub against each other the fibers do not snag as much. This reduces the development of the annoying fuzzing or abrasion that would normally develop with friction. The result is a combination effect that protects the fabric from both external chemicals and abrasion in turn extending the life of the garment.

Application Science: Optimizing Silicone Emulsion Finishing for Maximum Durability

Pad-Dry-Cure Parameters: Crosslink Density vs. Fiber Softness (180° C - 90 s)

Most manufacturers implement a standard pad-dry-cure process where the fabric is exposed to around 180 degrees Celsius for about 90 seconds because it achieves the desired results. The process creates just enough crosslinking to ensure that the silicone film is anchored to the fabric without compromising the fabric's elasticity and drapability. Going any higher than that temperature can cause the fabric to become *super* brittle especially for synthetic fabrics like polyester which is quite heat-sensitive. On the other hand, if the curing time is too short, the film will not even form, and therefore the water resistance will be *super* poor.  Industry tests have shown that 25 to 35 % crosslinking is optimal to achieve a 18 - 22 % increase in fiber strength (Textile Research Journal, 2023) while keeping the fabric soft. Real-time Infrared spectroscopy shows that the significant silanol condensation reactions, which are critical for optimal reactions, are fully completed within 85 seconds of the desired temperature.

Formulation Shift: Replacing Solvent Based Softeners for Denim and Knit Garments with Cationic Silicone Emulsions

Cationic silicone emulsions finishing agents for denim and knit garments are becoming very popular as they are very green and highly efficient. The Global Textile Sustainability Report of last year showed that water based formulations dramatically reduce VOC emissions compared to traditional solvent based softeners, up to 92% less. So, what makes these emulsions so effective? The reason they are more effective is that they are attracted to and stick to cotton fibers, which allows manufacturers to achieve the same softness with 30% less product. Reports from knit producers say they have seen an up to 42% reduction in broken knitting needle and line speed increase by up to 15% because of less friction cause by the use of cationic silicone emulsions. In addition, these new emulsions are almost 37% better than the older softener tech in fabric abrasion testing under ASTM D3886. Besides helping to comply with strict ZDHC MRSL guidelines, using cationic silicone emulsions shows an improvement in the wear of the fabric, which customers can notice.

Tests Have Shown Silicone Emulsions Perform Better Than Conventional Softeners With Real World Durability Measures 

Improved Abrasion Resistance: 42% Higher In Polyamide Blends (AATCC 117)

Testing for the AATCC 117 standard, polyamide blends with silicone emulsion finishes demonstrate 42% higher resistance to abrasion than polyamide blends finished with conventional softeners. How is this possible? Silicone provides dual functionality. The flexible siloxane chains dissipate mechanical stress during normal use, while the hydrophobic siloxane chains shield the fabric from dirt and limit the wear and tear that is caused by the fabric being wet. In the end, the materials treated with silicone emulsions retain a protective layer for more than 50 commercial laundry cycles, and that’s after 50 cycles, which means the manufacturer’s investment is justified for products designed for extreme abuse, like sports clothing where fabric integrity is critical.

Trade-offs Between Pilling and Tensile Retention in Polyester-Cotton Blends 

Silicone emulsions as applied to polyester-cotton blends result in a pilling reduction of about 35% based on the ISO 12945-2 standards because the emulsion modifies the fibers to slide over each other better, thus reducing the formation of the pilling that occurs on the surface of fabrics. Of course, it must be mentioned that an emulsifier that reduces pilling, reduces the fabric strength as well. Tests indicate that the tensile strength of an emulsion-treated fabric is 5 to 8% less than that of the untreated fabric. This is the reason that manufacturers must be cautious of their dosages. Silicone applications of less than 4% of the fabric's weight have been shown to offer the pilling resistance needed while not reducing the strength too much for everyday use fabrics. Finding this balance is even more important on knits where the customer can see individual pilling on their sweaters. This balance means that clothes stay looking new for longer, but they do not become damaged and unusable after a few washes.

FAQ Section

What is the most significant advantage of using silicone emulsion on fabrics? 

Silicone emulsion of fabrics caused a significant reduction in pilling and associated increases in strength retention of the fabric, thereby prolonging the useful life of the fabric.

How does silicone emulsion affect surface energy in textiles?

Silicone emulsions decrease surface energy in textiles to increase their resistance to water and moisture.

Why are cationic silicone emulsions preferred in denim and knit manufacturing?

Because they are more environmentally sustainable, cationic silicone emulsions decrease the amount of VOCs and increase the softening and the overall production rate of the fabric.

What are the trade-offs when using silicone emulsion on polyester-cotton blends?

Silicone emulsions decrease the pilling of fabrics, however they may also decrease the strength of the fabric, resulting in the need of more precise control of the emulsion.