Conventional Dimethyl Silicone Oil Emulsion

I. Product Properties

II. Advantages for Hydrophobic Treatment of Glass Fiber

1. Low cost with high cost performance and affordable raw materials.
2. Instant hydrophobic effect: water beads form distinctly right after treatment.
3. It provides lubrication simultaneously, making glass fibers smooth, less prone to fuzzing and fluffier.
4. Water-based system with simple dilution, stable at ambient temperature and resistant to demulsification at low concentrations.
5. It does not affect the whiteness of glass fibers and will not cause yellowing.

III. Critical Drawbacks (Major Defect for Long-term Waterproofing of Glass Fiber)

1. Extremely poor adhesion and non-durable hydrophobicity
   Without chemical bonding with glass fibers, the silicone merely floats on the surface. When exposed to water washing, rain or high-humidity environments, the silicone is quickly washed away, and the hydrophobic performance declines sharply within a few days. It is completely unsuitable for outdoor use or filter materials.
2. Prone to migration and oil bleeding under high temperature
   During drying or post-processing of glass fibers above 200℃, the silicone oil will separate and bleed out freely, leaving oily surfaces on glass fibers, sticking rollers and finished products. Subsequent resin lamination or film lamination will suffer delamination, poor adhesion and failure of printing performance.
3. Non-dense film layer with poor soaking resistance
   Waterproof performance fails completely after prolonged soaking, only suitable for short-term moisture-proofing.
4. Silicone easily rubs off
   Hydrophobicity deteriorates rapidly after repeated rubbing of glass fiber felts and filter cotton.

IV. Applicable Glass Fiber Scenarios Only (Short-term Indoor Moisture Resistance Only)

1. Disposable indoor glass fiber cotton and packaging filling glass fibers requiring short-term moisture resistance in dry environments.
2. Low-end glass fiber semi-finished products that only need lubrication and temporary waterproofing without long-term rain or water immersion exposure.
3. Simple semi-finished glass fiber products without resin lamination or high-temperature post-processing.

V. Completely Unsuitable Scenarios

VI. On-site Application Process of Conventional Silicone Emulsion for Glass Fiber

1. Dilution ratio: dilute with clean water to a working liquid solid content of 5%–10%.
2. Application methods: spray, pad dip, or mix a small amount into glass fiber sizing agent.
3. Drying conditions: only evaporate moisture at 80–120℃; higher temperatures will accelerate silicone oil separation and oil bleeding.
4. Dosage: 0.2%–0.5% by dry weight of glass fiber; excessive dosage inevitably causes fiber adhesion due to oil bleeding.
5. Compatibility taboo: anionic conventional silicone emulsion cannot be mixed with cationic sizing agents or cationic additives, otherwise direct demulsification and stratification will occur.

VII. Low-cost Compounding Formulas for Improved Durability

1. Mix conventional silicone emulsion and hydroxyl silicone emulsion at a ratio of 7:3. The introduced crosslinkable groups greatly enhance resistance to water washing.
2. Add a small amount of water-based silane coupling agent KH550. The silane anchors to the silica surface of glass fibers to lock the silicone layer and reduce shedding and migration.

VIII. Performance Comparison: Conventional Silicone Emulsion vs. Hydroxyl Reactive Silicone Emulsion

Summary & Recommendations

1. Choose conventional dimethyl silicone oil emulsion for temporary short-term waterproofing in dry indoor environments with limited budget.
2. For glass fibers requiring long-term hydrophobicity, water contact, outdoor service, filter material application or subsequent composite bonding: Do not use conventional dimethyl silicone oil emulsion alone. Prioritize hydroxyl self-crosslinking silicone emulsion, or improve performance by compounding hydroxyl silicone emulsion with silane coupling agent.