Amino-Modified Polyorganosiloxane Softener

I. Amino Silicone Oil Softener

The active components of amino silicone oil softeners consist primarily of copolymers of modified amino silane coupling agents and dimethylsiloxane. This structure allows amino silicone oil to interact with functional groups such as hydroxyl and carboxyl on the fiber surface.

Amino silicone oil forms chemical or hydrogen bonds with polar groups on the fiber surface through the amino groups, promoting the directional adsorption of the siloxane backbone onto the fiber surface. This directional adsorption reduces the coefficient of friction between fibers, imparting excellent softness and smoothness to textiles.

Application Range

Amino silicone oil softeners are suitable for softening a wide range of synthetic and natural fibers and are widely used for treating materials such as acrylic and polyester staple fibers. By treating these materials with amino silicone oil, they can achieve styles similar to animal fur or feathers, often used in products such as filling cotton.

Relationship Between Molecular Structure and Softening Effect

The molecular structure of amino silicone oil, particularly its amine value (amino group content) and viscosity, significantly affects its softening effect. Generally, when the amine value is low, viscosity needs to be appropriately increased to maintain the softening effect. Choosing the right amine value and viscosity based on fabric type and quality requirements can optimize the softening effect.

Impact of Formulation Process

The formulation process of amino silicone oil emulsions also plays a critical role in the softening effect and the stability of the finishing process. Choosing the appropriate type of amino silicone oil and combining it with the proper formulation process can create softeners that meet the needs of various fabrics.

Preparation Process

1. Amine Neutralization:?The amino groups in amino silicone oil are neutralized with acid to enhance emulsification and dispersion, aiding in the formation of microemulsions.

2. Microemulsion Preparation:?The prepared microemulsion has particle sizes smaller than 50 nm, high transparency, and high stability against mechanical and thermal stress, preventing demulsification and oil separation during the finishing process.

3. Surfactant Selection:?Non-ionic, cationic, anionic, or amphoteric surfactants can be used. Non-ionic or amphoteric surfactants are typically preferred to ensure compatibility with other ionic additives.

1. Non-Ionic Surfactants:?Include polyethylene alkyl ethers, polyethylene isomerized alkyl ethers, polyethylene alkyl esters, etc. Different HLB-value surfactants can be used together for optimal emulsification.

4. Surfactant Dosage:?The recommended dosage is 30–70 parts to ensure the formation of microemulsions with oil particle sizes less than 100 nm, while avoiding excessive residues that could affect performance.

5. Choice of Neutralizing Acids:?Organic carboxylic acids such as formic acid, acetic acid, propionic acid, or amino-containing acids like glutamic acid, DL-aspartic acid, or sulfamic acid can be used.

6. Emulsification Method:?High-speed homogenizers or other emulsification devices are typically used. The acid can be added after emulsification or together with water. Alternatively, the amino silicone oil and surfactant can be mixed first, followed by the addition of acid and water.

7. Water Usage:?The amount of water ranges from 40 to 5000 parts, adjusted as needed.

8. Post-Treatment:?After adding the acid, the solution is treated at 60–80°C for 3–20 hours to promote the hydrophilization of the amino silicone oil and the refinement of the emulsion particles.

Application Example

Formulation Preparation: In a 2L beaker, add 150g of amino silicone oil and 15g of polyethylene lauryl ether. Stir at high speed, then slowly add 800g of water and 1.1g of acetic acid, continuing to stir until a white emulsion forms.

Post-Treatment: Transfer the emulsion to a 2L flask and stir at 80°C with a paddle stirrer for 4 hours to obtain a blue-white transparent microemulsion with an average oil particle size of 80 nm.

Performance: This microemulsion softener exhibits good storage stability, dilution stability, and mechanical stability. No demulsification occurs after one year of storage at room temperature.

Enhancers: Adding diols such as ethylene glycol monomethyl ether or diethylene glycol monomethyl ether can further improve the microemulsion's stability, dilution stability, mechanical stability, and transparency.

Amino silicone oil is widely used in textile softeners due to its excellent softness and smoothness.

II. Amphoteric Surfactant-Based Amino Silicone Oil Softener

Characteristics: Microemulsions prepared using amphoteric surfactants offer simple processing, good reproducibility, and low usage levels. These microemulsions exhibit high shear stability and do not demulsify during the textile finishing process, resulting in excellent softness and smoothness.

Surfactant Selection: Amphoteric surfactants containing at least one long-chain alkyl group, such as amine oxides, betaines, or sulfobetaine, can be used in amounts of 5% to 20%.

Alcohol Additives: Alkanols such as isobutanol should also be added to the formulation, with usage levels between 5% and 25%.

Formulation Method: The amino silicone oil, amphoteric surfactant, alcohol, and a small amount of water are first mixed into a concentrate, which is then diluted with water. The water content in the concentrate should be 2 to 5 times the amount of the surfactant.

Application Example: Specific formulation steps can produce amino silicone oil microemulsions with various particle sizes and properties, used for softening cotton and other textiles, imparting softness, smoothness, elasticity, and good recovery.

Stability Improvement: Combining non-ionic surfactants and solubilizers can further improve the microemulsion's shear stability.

III. Amino Silicone Oil Emulsion Softener without Acid

Formulation Principle: When emulsifying amino silicone oil, acid is added to form quaternary ammonium salts, enhancing the polarity of the silicone oil and making it easier to disperse in water to form a microemulsion. However, an excess of quaternary ammonium salts may affect the softening effect.

Choice of Emulsifiers: To achieve stable emulsions, use two or more types of branched alkyl ether emulsifiers with different HLB values. These emulsifiers allow the preparation of emulsions with particle sizes ranging from 50 to 250 nm, without the need for, or with minimal use of, acid.

Application Effect: This type of emulsion can impart softness and smoothness to various fibers and has good adsorption onto fibers.

IV. Amino Silicone Oil Softener Prepared by Emulsion Polymerization

Polymerization Method: Through the emulsion polymerization method, modified amino silane coupling agents and other raw materials are emulsified and dispersed in water in the presence of cationic and nonionic surfactants. Then, a base catalyst is added to initiate the ring-opening polymerization.

Product Characteristics: The resulting amino silicone oil microemulsion has good stability and is suitable for improving the resilience and wash resistance of fabrics.

Stability and Effect Comparison: Compared to microemulsions prepared by simply emulsifying amino silicone oil, products made by the emulsion polymerization method may contain residual siloxane oligomers, which can easily contaminate finishing equipment. Additionally, the softening and smoothing effects are slightly inferior.

Self-Crosslinking Amino Silicone Oil Emulsion Preparation

Crosslinking Principle: By adding trifunctional alkoxysilane into the amino silicone oil emulsion, a self-crosslinking structure is formed through polymerization.

Stability and Effect: An appropriate amount of trifunctional silane can improve fabric resilience, but excessive amounts may affect the emulsion’s stability.

Application Effect: The treated fabric has a soft hand feel, with enhanced resilience and wash resistance.