Can amino silicone oil be used?
Absolutely, and in polyester fabric coating, amino silicone oil is often a better choice, especially for meeting adhesion, hand feel, and functional requirements. Here is a detailed analysis:
1. Characteristics and advantages of amino silicone oil
Amino silicone oil is a modified silicone oil with amino groups (-NH₂ or -NHR) introduced into the molecular chain. Compared with dimethyl silicone oil, its core advantages are:
- Stronger polarity and excellent adhesion: Amino groups are polar and can form hydrogen bonds or dipole interactions with ester groups (-COO-) on the surface of polyester fabric, solving the problem of insufficient adhesion of dimethyl silicone oil. The film is more resistant to friction and water washing;
- Softer and smoother hand feel: Amino silicone oil can form an oriented film on the fiber surface, endowing the fabric with a delicate and fluffy hand feel, making it a common material for textile softening finishing;
- Easy to cure: Amino groups can react with cross-linking agents (such as epoxy-based or isocyanate-based) or under acidic conditions to achieve chemical curing without extremely high temperatures.
2. Applicable scenarios of amino silicone oil
Compared with dimethyl silicone oil, amino silicone oil is more suitable for the following needs:
- Focusing on fabric soft hand feel and anti-pilling (such as clothing fabrics, home textile fabrics);
- Requiring strong film adhesion and water-wash resistance (such as outdoor fabrics, workwear fabrics);
- No need for extreme waterproofness (the waterproofness of amino silicone oil is slightly lower than that of pure dimethyl silicone oil, but it can be balanced by adjusting the structure).
3. Curing methods of amino silicone oil
The curing of amino silicone oil relies on the reaction between amino groups and cross-linking agents. Common processes are:
- Cross-linking agent matching: Add a small amount of epoxy silane (such as KH-560), isocyanate cross-linking agents, or adjust the pH to weakly acidic (pH 4-6) with organic acids (such as formic acid or acetic acid) to promote the combination of amino groups with fibers/cross-linking agents;
- Curing conditions: Slow curing can occur at room temperature, and medium-temperature (80-120°C) baking can accelerate the reaction, improving curing efficiency and film fastness;
- Note: Avoid excessive cross-linking agents that may make the fabric stiff; adjust the ratio through small sample tests.
4. Comparative selection with dimethyl silicone oil
| Dimension | Dimethyl Silicone Oil | Amino Silicone Oil |
|---|---|---|
| Adhesion | Poor (non-polar) | Excellent (enhanced by polar amino groups) |
| Hand Feel | Smooth but slightly stiff | Soft, fluffy, and delicate |
| Waterproofness | Better (low surface tension) | Moderate (optimizable via modification) |
| Curing Difficulty | Requires reactive groups + high temperature/cross-linking agents | Curable at room/medium temperature |
| Water-Wash Resistance | Poor | Good |
Summary
- Curing of dimethyl silicone oil: Ordinary models are difficult to cure. It is necessary to use hydroxyl/vinyl modified silicone oil, match with cross-linking agents (such as tetraethyl orthosilicate + organotin catalyst) or peroxides, and achieve chemical cross-linking at medium to high temperatures;
- Amino silicone oil is recommended: It is particularly suitable for polyester fabric coating, with better adhesion, hand feel, and curing convenience than dimethyl silicone oil. It is more suitable for scenarios focusing on softness and water-wash resistance. Curing can be achieved through weakly acidic conditions or adding epoxy/isocyanate cross-linking agents, with a simpler process.
If your requirement is to balance functionality and practicality, prioritize amino silicone oil and further optimize the effect through pre-treatment (corona/plasma) + an appropriate amount of cross-linking agent.
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