The synthesis process of ternary copolymerized silicone softeners is primarily based on the design and functional modification of block copolymers, aiming to address issues such as poor hydrophilicity, yellowing tendency, and insufficient emulsion stability in traditional silicone softeners. Below is a summary of the key synthesis steps, compiled from multiple literature sources and patents:
I. Core Synthesis Steps
(1).Synthesis of Epoxy-Terminated Silicone Oil
Using octamethylcyclotetrasiloxane (D4) and epoxy-terminating agents as raw materials, ring-opening polymerization is carried out under a catalyst (e.g., acidic or alkaline catalyst) to produce epoxy-terminated siloxane prepolymers. This step typically requires a temperature range of 70–130°C and a reaction time of 4–8 hours, yielding epoxy-terminated silicone oil with a molecular weight range of 8,000–14,000 g/mol.
(2).Block Copolymerization Reaction
Construction of Ternary Block Structure: Epoxy-terminated silicone oil is reacted with amino polyethers (e.g., polyetheramine ED series) and small-molecule organic amines (e.g., ethylenediamine, propylenediamine) at a molar ratio ranging from (1:1:1) to (1:1:2). The introduction of amino polyethers enhances hydrophilicity, while small-molecule organic amines promote crosslinking, forming the backbone of the block copolymer.
Introduction of Crosslinking Agents: A crosslinking agent (e.g., 3-(2,3-epoxypropoxy)propyltrimethoxysilane) is added, and the reaction proceeds at 70–130°C for 4 hours to form a three-dimensional network structure (T-branched chains), significantly improving wash resistance and emulsion stability.
(3).Hydrophilic Modification
Hydrophilic modifiers (e.g., 2,3-epoxypropyltrimethylammonium chloride) are used for terminal modification of the block copolymer, introducing cationic groups to further enhance hydrophilicity and anti-yellowing properties.
II. Key Process Optimizations
(1).Solvent Selection and Environmental Considerations
Common solvents include isopropanol and ethylene glycol butyl ether, with usage controlled at 10%–30% of the total mass to reduce environmental impact.
Some processes employ self-emulsification techniques (e.g., direct dilution with water) to eliminate emulsifiers, simplifying the process and reducing costs.
(2).Reaction Condition Control
Temperature range: 70–130°C, with staged heating to avoid side reactions.
Vacuum dehydration: During chain extension polymerization, byproduct water is removed under vacuum to ensure reaction efficiency.
(3).Structural Design Innovations
Hyperbranched Structure: Condensation reactions between allyl polyoxyethylene polyoxypropylene glycidyl ether (e.g., Danwei Technology’s epoxy-terminated polyether) and epoxy-terminated polyether siloxane form a hyperbranched-linear composite structure, improving fiber cohesion and wash resistance.
Dual-Functional Modification: Combining epoxy and amino polyether modifications imparts multifunctional properties such as softness, hydrophilicity, and antistatic performance to fabrics.
III. Performance Advantages and Applications
(1).Performance Characteristics
Low Yellowing: Reduced free amine content and the introduction of stable crosslinked structures significantly minimize yellowing at high temperatures.
High Stability: Self-emulsification technology prevents emulsion stratification or oil separation during storage and padding.
Wash Resistance: The three-dimensional network structure enhances chemical bonding with fibers, achieving over 20 wash cycles.
(2).Application Techniques
Padding Method: Dosage of 20–80 g/L, pre-drying at 120°C, and curing at 150–180°C.
Dipping Method: Dosage of 2%–5% (o.w.f), treatment time of 20–30 minutes, suitable for synthetic fibers, cotton, and blended fabrics.
IV. Future Trends
Future processes will focus more on environmental friendliness and efficiency:
(1).Solvent Alternatives: Development of water-based or solvent-free synthesis routes to reduce VOC emissions.
(2).Functional Integration: Designing multifunctional copolymers to meet demands such as cooling and antistatic properties.
(3).Process Simplification: Improving efficiency through one-step polymerization or continuous production, as seen in patent CN104650363A for hyperbranched processes.
Summary
The above process integrates block design, crosslinking modification, and environmental optimization, providing technical support for the industrial production of ternary copolymerized silicone softeners. Specific implementation requires further parameter adjustments based on raw material characteristics and target performance.
