In silicone-coated glove production, bubbling is one of the most common yet often misunderstood defects. Many users immediately assume it is a material issue, but in reality, it is usually the result of a combination of material behavior, coating process, fabric condition, and curing control.
Bubbles not only affect appearance but can also weaken adhesion and reduce anti-slip performance. In severe cases, they may lead to partial coating failure. Therefore, understanding the real root cause is far more important than simply treating the surface symptom.
Why does silicone coating on gloves form bubbles?
At its core, bubbling happens because air or gas is trapped inside the silicone system and cannot escape before curing. However, the sources of this trapped gas can come from multiple stages of the process.
During the mixing stage, improper blending of A/B components or overly fast stirring can introduce large amounts of micro air into the silicone. If no vacuum degassing is applied, these bubbles remain inside the material and are carried into the coating process.
During application (dot, line, or coating), unstable dispensing pressure, inconsistent flow, or rapid needle retraction can also pull air into the silicone stream, creating localized bubble formation.
Another major source is the fabric itself. Knitted gloves made of polyester or nylon often contain trapped air, moisture, or chemical residues inside the fiber structure. During heating and curing, these gases are released. If the silicone surface has already started to form a skin layer, the gas becomes trapped underneath, forming visible bubbles or internal voids.
Why do different coating structures show different bubbling behavior?
Although bubbling can occur in all coating types-dot, line, grid, and full coating-the way it appears is different because of structural geometry.
In dot (anti-slip) coating, bubbles usually appear as individual hollow or swollen dots. Since each dot is independent, defects remain localized.
In line coating, bubbles often follow the dispensing path, forming intermittent swelling or breaks along the line. This is closely related to movement speed and flow stability.
In grid coating, bubbles tend to concentrate at intersection points, where material overlaps and stress is higher. These nodes are more prone to trapped air and uneven curing.
In full coating, the issue becomes more severe and systemic. If gas cannot escape during curing, large-area bubbling or even complete layer lifting may occur.
How can bubbling in silicone glove coating be solved?
Solving bubbling issues requires controlling the entire process rather than focusing on a single step.
In the material preparation stage, air introduction must be minimized. Vacuum degassing is highly recommended, and mixing speed should be controlled to avoid air entrapment.
During application, stable dispensing pressure and continuous flow are critical. Sudden stops, retraction, or pressure fluctuations should be avoided as they directly introduce air into the system.
Fabric pre-treatment is also essential. Pre-drying the gloves helps remove moisture and residual chemicals trapped in the fibers, which otherwise release gas during curing.
Finally, curing control plays a key role. If temperature rises too quickly, the silicone surface may seal too early, preventing internal gas from escaping and leading to trapped bubbles. A controlled curing profile allows gases to release gradually before full crosslinking.
Conclusion
Bubbling in silicone glove coating is not a single-factor defect but a classic gas entrapment and release imbalance problem throughout the entire process chain.
It can be summarized in three principles:
Air should not be introduced during mixing
Air should not be trapped during coating
Air must have time to escape during curing
When these three conditions are properly controlled, bubbling can be significantly reduced across all structures-dot, line, grid, and full coating-resulting in stable, high-quality silicone-coated gloves.