Amino‑modified silicone oil is a class of organosilicon‑modified polymers incorporating amino functional groups onto the polydimethylsiloxane (PDMS) backbone. It combines the exceptional flexibility, thermal stability, and hydrophobicity of the siloxane skeleton with the strong polarity, reactivity, and protein‑binding affinity of amino groups, forming a unique amphiphilic molecular characteristic. It serves as the core category of reactive organosilicon auxiliaries.
I. Chemical Structure and Classification
1. Basic Structure
Molecular formula: R₁(CH₃)₂SiO[(CH₃)₂SiO]ₘ[(R₂)(CH₃)SiO]ₙSi(CH₃)₂R₁
- R₁: Methyl (inactive) or hydroxyl/methoxy (active)
- R₂: Aminoalkyl group (e.g., aminopropyl, aminoethylaminopropyl)
Amino groups are connected to silicon atoms via propyl spacer chains, preventing instability caused by direct interaction between amino groups and siloxane bonds.
2. Main Classification Methods
| Classification Criterion | Type | Characteristics and Application Scenarios |
|---|---|---|
| Amino Position | Side‑chain type (60% market share) | General standard grade with fluffy hand feel, suitable for most textiles |
| Terminal amino type (α,ω‑diamino terminal) | Dense film formation, excellent wash fastness, firm and smooth hand feel, mostly used for high‑end knitwear and leather | |
| Single‑end type/copolymer type/hybrid type | Special applications such as fiber lubricants and resin modifiers | |
| Amino Type | Monoamine type | Low yellowing tendency, suitable for white/light‑colored fabrics |
| Diamine type (aminoethylaminopropyl) | Superior softness and smoothness, significant yellowing tendency, suitable for dark‑colored fabrics | |
| Functional Modification | Epoxy modification | Enhances reactivity with fibers and improves wash fastness |
| Polyether modification | Increases hydrophilicity and antistatic properties | |
| Long‑chain alkyl modification | Enhances smoothness and hydrophobic effect | |
| Fluorine modification | Imparts superhydrophobic and antifouling properties |
II. Core Performance Parameters and Characteristics
1. Key Technical Indicators
| Parameter | Typical Range | Impact and Significance |
|---|---|---|
| Amine Value | 0.2~1.2 mmol/g | Higher amine value means better softness and smoothness, but more yellowing and stronger affinity for fibers |
| Viscosity | 100~1,000,000 mPa·s (25°C) | Higher viscosity results in better film‑forming ability and thicker hand feel, but increases processing difficulty |
| Density | 0.98 g/cm³ (25°C) | Lighter than water, facilitating emulsion preparation and application |
| Refractive Index | 1.404~1.408 (25°C) | Matches fiber refractive index without affecting fabric transparency |
| Volatile Content | ≤4% (150°C, 3h) | Low volatile content indicates good thermal stability and minimal loss during processing中国氟硅有... |
2. Core Performance Characteristics
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Excellent softness and smoothness: The siloxane main chain provides low surface tension, significantly reducing friction between fibers and endowing fabrics with a "silky smooth" hand feel.
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Strong adsorption and reactivity: Amino groups are cationic (pH 7‑9), forming hydrogen bonds and electrostatic interactions with hydroxyl/carboxyl groups on fiber surfaces, enabling oriented adsorption and firm bonding, thus improving wash fastness.
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Multifunctional finishing effects: Enhances fabric tear strength, wrinkle resistance, and elasticity, improves drapability, and provides long‑lasting antistatic properties.
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Good compatibility and emulsifiability: Can be compounded with various organosilicon or organic softeners to form stable, transparent microemulsions, facilitating processing and application.
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Excellent thermal stability: The siloxane skeleton provides good thermal stability, suitable for high‑temperature setting processes.
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Yellowing tendency: Diamine‑type amino silicone oils tend to yellow under high temperature or light, while monoamine‑type or modified types can significantly reduce yellowing risk.
III. Main Application Fields
1. Textile Industry (Core Application with Highest Proportion)
| Application Scenario | Functional Effects | Suitable Fabrics |
|---|---|---|
| Fabric Finishing | Imparts soft and smooth hand feel, enhances elasticity and wrinkle resistance, reduces shrinkage rate, improves drapability | Cotton, wool, silk, linen, polyester, nylon, spandex, and blended fabrics |
| Fiber Spinning | Reduces friction between fibers, prevents yarn breakage, improves spinning efficiency and yarn quality | Component of synthetic fiber spinning oils |
| Knitwear Finishing | Enhances elasticity and recovery, improves sewability, reduces pilling tendency | Knitwear, stretch fabrics, sportswear |
| Functional Fabrics | Compounded with waterproof, antibacterial, and other functional finishing agents to enhance comprehensive performance | Outdoor clothing, medical textiles, home textiles |
Application Notes: Low amine value (0.2‑0.6) for lightweight fabrics and white textiles; medium amine value (0.6‑0.9) for ordinary fabrics; high amine value (0.9‑1.2) for heavy fabrics and dark‑colored textiles.
2. Personal Care Field
Hair Care Products: Core ingredient in shampoos, conditioners, hair masks, and hair care oils
- Smoothes hair cuticles, reduces combing force, minimizes frizz and split ends
- Forms a protective film, locks in moisture, repairs perm and dye damage, enhances luster
- Provides long‑lasting antistatic effect, making hair soft and easy to manage
Skin Care Products: Additive in high‑end facial creams, body lotions, and hand creams
- Provides silky skin feel, improves product spreadability and extensibility
- Enhances moisturizing effect, forms a breathable hydrophobic film on skin surface to reduce water loss
3. Leather and Paper Industry
Leather Treatment:
- Leather feel agent: Imparts soft, smooth, and plump touch, enhances tear strength
- Leather waterproofing agent: Enhances hydrophobicity and improves durability
- Leather coating additive: Improves coating flexibility and glossiness
Paper Industry:
- Paper softener: Improves softness and water absorption of toilet paper, facial tissues, etc.
- Paper antistatic agent: Improves printability and paper processing performance
4. Other Application Fields
Coatings and Inks:
- Leveling agent and anti‑crater agent: Improves coating surface properties and reduces orange peel effect
- Slip agent: Enhances coating wear resistance and scratch resistance
- Defoamer component: Suitable for water‑based coating systems
Furniture and Wood:
- Wood floor and furniture polish: Provides long‑lasting luster and protection, enhances wear resistance
- Wood waterproofing agent: Extends service life
Resin Modification:
- Modifier for polyurethane and epoxy resins: Improves flexibility, adhesion, and weather resistance
- Enhances impact resistance and hydrophobicity of composite materials
IV. Application Considerations
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pH Value Control: Amino silicone oil is weakly alkaline (pH 7‑9). Direct mixing with strong acidic substances should be avoided to prevent amino protonation that affects performance.
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Compatibility Restrictions: May form precipitates with anionic surfactants (e.g., sodium lauryl sulfate). Nonionic or cationic emulsifiers should be selected for compounding.
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Yellowing Control: For white/light‑colored fabrics, low‑yellowing monoamine‑type or modified amino silicone oils are preferred, and prolonged high‑temperature treatment should be avoided.
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Emulsion Stability: Select a matching emulsification system and control particle size at the nanometer level to ensure long‑term emulsion stability and prevent stratification.
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Dosage Optimization: Excessive use may cause fabrics to have an "oily" or "waxy" feel. The typical dosage is 0.1%‑3% of fabric weight, adjusted according to fabric type and amine value.
V. Development Trends
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Low Yellowing and High Wash Fastness: Optimization of monoamine structure and new modification technologies to solve yellowing issues and improve wash fastness.
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Functional Complexity: Multi‑component modification combining amino groups with epoxy, polyether, long‑chain alkyl, fluorine, etc., to meet specific application requirements.
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Environmental Friendliness: Development of low‑VOC and biodegradable amino silicone oils to comply with green production trends.
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Microemulsification: Nanoscale microemulsion technology enhances application effects, reduces dosage, and improves cost‑effectiveness.
With its unique molecular structure and multifunctional properties, amino‑modified silicone oil has become an indispensable key material in textile, daily chemical, and other industries. In the future, with technological innovation, its application fields will be further expanded, and its performance will be continuously optimized.
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