The synthesis processes of silicone wetting agents vary depending on their chemical structure, functional requirements, and application fields. Below are several synthesis methods and their characteristics:
1. High-Temperature and Hydrolysis-Resistant Silicone Wetting Agent
(1).Raw Materials
Main components: Trisiloxane ethoxylate (TRSE), polyether, fluorinated compounds (e.g., perfluorooctyl sulfonamide, perfluorobutyl sulfonic acid).
Catalyst: Platinum catalyst (e.g., 1% chloroplatinic acid in ethanol).
(2).Synthesis Steps
Mixing reaction: Trisiloxane ethoxylate (10–50 mol), polyether (5–40 mol), and fluorinated compounds (1–10 mol) are added to a reactor and heated to 85–135°C.
Catalytic reaction: A platinum catalyst is introduced under vigorous stirring, and the temperature is maintained for 2–4 hours.
Post-treatment: Byproducts are removed via vacuum distillation to obtain the final product.
(3).Key Parameters
Surface tension: <22.5 mN/m, stable in pH 2–12.
High-temperature stability: Maintains stable surface tension for 72–240 hours at 80–150°C.
Applications: Coatings, synthetic leather, textile coatings, and other industrial scenarios requiring high-temperature and hydrolysis resistance.
2. Pesticide-Use Silicone Wetting Agent
(1).Raw Materials
Hydrogen-containing silicone oil (e.g., heptamethyltrisiloxane), allyl polyether, nonionic surfactants (e.g., polyoxyethylene-polyoxypropylene block copolymer), polystyrene sulfonic acid.
Catalysts: Dilute hydrochloric acid, triethylenetriamine.
(2).Synthesis Steps
Precursor preparation: Hydrogen-containing silicone oil and allyl polyether undergo an addition reaction at 100–150°C for 5–8 hours to form a polyether-modified silicone precursor.
Modification reaction: The precursor is mixed with glycerol, polyvinyl alcohol, etc., followed by stepwise addition of catalysts (e.g., trimethylchlorosilane) at 50–80°C.
Compounding and thickening: Nonionic surfactants, polystyrene sulfonic acid, thickeners (e.g., carboxymethyl cellulose), and trace element chelates are incorporated.
(3).Characteristics
Enhances pesticide wettability, reduces surface tension, and improves foam resistance.
Incorporation of hydrophobic fluoroalkyl groups increases penetration and adhesion on nonpolar surfaces.
3. Reactive Silicone Wetting Agent
(1).Raw Materials & Reaction
Main components: Terminal hydrogen-containing silicone oil, allyl epoxy polyether.
Key step: A Grignard reaction (e.g., chloroethane/magnesium system) is used to react terminal hydrogen-containing silicone oil, followed by polycondensation with allyl epoxy polyether.
(2).Process Highlights
Reaction temperature: 20–80°C (Grignard reaction stage), ≤80°C for hydrolysis-polycondensation.
Molecular rearrangement: Concentrated sulfuric acid catalyzes rearrangement to optimize hydrophobicity-hydrophilicity balance.
(3).Advantages
Branched structure enhances wettability and stability, suitable for complex interfacial systems.
4. Hyperbranched Silicone Wetting Agent
(1).Synthesis Method
Raw materials: Terminal hydroxyl hyperbranched polymer, terminal epoxy silicone oil.
Reaction mechanism: Epoxy ring-opening reaction forms a hyperbranched network structure.
(2).Application Features
Significantly reduces surface tension in waterborne polyurethane, improving substrate wetting and leveling.
Ideal for leather, synthetic leather, and other fields requiring high dispersion and leveling performance.
5. Process Comparison & Optimization Directions
(1).Catalyst selection: Platinum catalysts suit high-temperature systems, while acidic catalysts (e.g., dilute HCl) are used for modification reactions.
(2).Functional design: Fluorinated compounds enhance hydrolysis resistance; polyether chains adjust hydrophilicity-hydrophobicity balance.
(3).Eco-friendly trends: Water-based formulations and low-VOC solutions are current R&D priorities.
Hangzhou Danwei Technology Co., Ltd. has specialized in specialty polyether development for over 20 years. For more product information and technical insights, visit our website: https://www.danweichem.com/
