I. Definition and chemical nature
Silicone softener is an organic polymer compound with polysiloxane (PDMS) as the main chain. By introducing functional groups such as methyl, amino, epoxy, and polyether groups on the siloxane skeleton, a modified polysiloxane with special surface properties is formed. The Si-O bond energy in its molecular structure is as high as 452kJ/mol, which gives the product excellent thermal stability, while the organic groups on the side chains determine how it interacts with the fiber. For example, amino-modified silicone forms hydrogen bonds with the hydroxyl groups of cotton fibers through the side chain amino groups, and can form a three-dimensional network structure under baking conditions of 150°C, reducing the bending stiffness of the fabric by more than 60%.

II. Technological evolution and product iteration
First generation: mechanically emulsified silicone oil
Represented by dimethyl silicone oil, an emulsion with a particle size of 5-10μm is formed by mechanical emulsification. Although this type of product can reduce the fiber friction coefficient, it lacks reactive groups and has poor washability. The softness decreases by 40% after 3 washes.
Second generation: Hydroxyl-terminated silicone oil
Hydroxyl groups are introduced at both ends of the molecular chain to react with fibers for esterification. The hydroxy silicone oil emulsion developed by Zhejiang Sci-Tech University reacts with cellulose at 180°C to form ester bonds, which increases the washing durability of cotton fabrics to 20 times, but the emulsion is not stable enough and is prone to oil bleaching.
Third generation: Block-modified silicone oil
Using a polyether-amino diblock structure, such as Huntsman's ULTRATEX® UHS product, a hydrophilic-hydrophobic double-layer structure is formed on the fiber surface through the phase separation of the siloxane main chain and the polyether side chain. This technology increases the water absorption of polyester fabrics from 3 seconds to 0.5 seconds while maintaining a 98% softness retention rate.

III. Environmental technology breakthroughs
Application of bio-based raw materials
35% of the active ingredients in Archroma's Siligen® EH1 product come from ethanol extracted from corn straw, and its D4, D5, and D6 siloxane content is less than 0.1%, which meets REACH regulations. When this product is used for recycled polyester finishing, it can reduce VOCs emissions by 42%.
Closed-loop production process
The TUBINGAL RISE technology of CHT in Germany uses recycled siloxane and recycled emulsifier to achieve 98% raw material recycling through supercritical CO2 extraction process. This process can reduce wastewater discharge by 15 tons and carbon footprint by 65% for every ton of softener produced.
Low-temperature cross-linking technology
The low-temperature catalytic system developed by domestic enterprises can complete the silicone oil cross-linking reaction at 80°C. Compared with the traditional 150°C process, energy consumption is reduced by 53%, and the yellowing problem of amino oxidation caused by high temperature is avoided, which is particularly suitable for light-colored fabric finishing.

IV. Market application pattern
In 2024, the global silicone softener market size will reach US$2.8 billion, of which block-modified products account for more than 60%. As the largest consumer country, China's annual demand exceeds 150,000 tons, and companies such as Demei Chemical and Runhe Materials occupy 45% of the market share. In the high-end field, Huntsman's amino-epoxy copolymer silicone oil has been used in Lululemon sports fabrics, reducing the elastic modulus of the fabric to 0.8MPa, reaching the international advanced level.