Amino silicone oil is an organosilicon polymer whose main molecular chain is composed of siloxane bonds (-Si-O-Si-), with amino functional groups (-NH₂) attached to the side chains or end groups. It is a functional silicone oil produced by chemically modifying ordinary dimethyl silicone oil to introduce active amino groups. The introduction of amino groups fundamentally changes the surface properties and reactivity of the silicone oil, transforming it from an inert, hydrophobic material into a high-performance specialty chemical with strong adsorption, excellent softness, and reactive cross-linking capabilities.

Main Characteristics of Amino Silicone Oil
Due to its unique molecular structure, amino silicone oil combines many excellent properties, making it an irreplaceable softening agent in many fields, especially in textile finishing.

I. Excellent Softness and Smoothness
This is the most core characteristic of amino silicone oil. The amino group has strong polarity and can form strong hydrogen bonds and electrostatic adsorption with hydroxyl and carboxyl groups on the fiber surface. This action allows the silicone oil molecules to firmly and directionally attach to the fiber surface, forming a continuous, flexible organosilicon film. This film significantly reduces the friction coefficient between fibers (smoothness) and the rigidity of the fibers themselves (softness), thus giving the fabric an unprecedented soft, smooth, and full hand feel.

II. Excellent Adsorption and Durability
Due to the strong polarity of the amino group, amino silicone oil exhibits excellent affinity for various fibers, especially natural fibers such as cotton, wool, and silk. It is not easily washed off during laundering, thus providing a long-lasting and washable softening effect, which is unmatched by many traditional softeners.

III. Good Emulsification and Compatibility
By selecting different emulsifiers and processes, amino silicone oil can be prepared into stable microemulsions. This makes it easy to disperse in aqueous working solutions and allows it to be used in the same bath with other textile auxiliaries (such as resins, waterproofing agents, etc.) under certain conditions, simplifying the processing procedures for textile manufacturers. IV. Modifiable Reactivity
Amino groups (especially primary amino groups) possess certain reactivity.  They can not only bind to fibers but also react with resin crosslinking agents or carbon dioxide in the air under heating conditions, forming a more robust network film and further enhancing the durability of the finishing effect. Furthermore, by changing the amine value (amino group content), molecular weight, and amine value distribution, its properties can be precisely controlled, for example, achieving different handfeels ranging from extremely soft to elastic recovery.

V. Impact on Fabric Whiteness (Points to Note)
Amino groups, particularly primary amino groups, may oxidize and yellow at high temperatures or during prolonged storage, leading to yellowing of light-colored or white fabrics. This is a drawback of amino silicone oil. To address this problem, low-yellowing or ultra-low-yellowing modified amino silicone oils (such as cyclohexylamino and secondary amino modified products) have been developed in the industry.

In summary, amino silicone oil, with its unique combination of "strong polar adsorption" and "flexible siloxane chains," has become a key material for achieving high-quality fabric softening finishes.