Bubbling is a common problem during the production of silicone heat transfer transfers for gloves. In many cases, the bubbles appear before the transfer is even heat pressed onto the glove.
Manufacturers often notice:
Small bubbles inside the silicone layer
Raised spots on the transfer surface
Blistering during drying
Air holes inside the hot melt adhesive layer
Uneven transfer surfaces after curing
This problem usually occurs during the transfer production process on PET film, rather than during final transfer onto the glove.
Because glove transfer silicone printing involves multiple layers, including silicone, color layers, hot melt adhesive, and PET release film, any trapped air, unstable curing, or improper printing condition can create bubbling defects inside the transfer structure.
Why Bubbles Appear During Transfer Silicone Printing
One of the most common causes is air trapped during silicone mixing. When silicone and catalyst are mixed too aggressively, air enters the material and forms small bubbles inside the silicone paste. If the trapped air is not released before printing, the bubbles expand during drying or curing and appear on the transfer surface.
This problem becomes more obvious when:
Mixing speed is too fast
Silicone viscosity is too high
Silicone rests for insufficient time
No vacuum degassing process is used
Screen printing parameters can also create bubbling issues. If the screen mesh is too low, excessive silicone thickness may trap air inside the printed layer. Thick deposits reduce air release during drying and increase the risk of internal blistering.
Improper squeegee pressure is another important factor. Excessive printing pressure may force air into the silicone layer during printing, while unstable squeegee movement can create uneven silicone distribution and localized bubbles.
The PET release film also affects bubble formation. If the PET surface contains dust, moisture, oil contamination, or uneven release coating, air pockets may form between the silicone layer and the film surface. During heating, these trapped areas expand and create visible bubbling defects.
Drying and curing conditions are extremely important in transfer silicone production. If the drying temperature rises too quickly, the silicone surface may cure first while internal air or solvent remains trapped underneath. As the internal pressure increases during heating, bubbles form inside the layer.
Overheating can make the problem worse. Excessive oven temperature may cause rapid expansion of trapped air, especially in thick silicone areas or multilayer transfer structures.
Hot melt adhesive printing can also contribute to bubbling. If the adhesive layer is printed too thick or unevenly, airflow during curing becomes restricted. Moisture or air trapped inside the adhesive layer may later expand during secondary heating or transfer pressing.
Humidity inside the production environment is another hidden cause. In high-humidity conditions, moisture can collect on PET film surfaces or mix into the silicone and adhesive layers. During drying, the moisture evaporates and creates blistering inside the transfer structure.
Dust contamination is also common in transfer printing workshops. Small particles trapped between layers can prevent smooth silicone flow and create localized air pockets that later become visible bubbles.
How to Reduce Bubbling During Transfer Silicone Production
To reduce bubbling problems, silicone should be mixed slowly and evenly to minimize air intake. After mixing, allowing the silicone to rest or using vacuum degassing equipment can help remove trapped air before printing.
Screen mesh selection, squeegee hardness, and printing pressure should be optimized to avoid excessive silicone thickness and unstable coating distribution.
The PET release film must remain clean and dry before printing. Dust, oil, and moisture contamination should be strictly controlled inside the production area.
Drying temperature should increase gradually to allow internal air and moisture to escape before the silicone surface fully cures. Thick silicone structures may require slower curing conditions to improve air release stability.
Hot melt adhesive thickness should also remain controlled to avoid excessive internal pressure during curing and heat transfer.
For high-quality glove transfer production, stable workshop temperature and humidity control are equally important.
Conclusion
Bubbles during silicone heat transfer production for gloves are usually caused by trapped air, unstable curing, excessive silicone thickness, moisture contamination, or improper printing conditions. Factors such as silicone mixing, screen printing parameters, PET film cleanliness, drying temperature, and adhesive coating stability all directly affect bubble formation.
By optimizing material preparation, printing conditions, curing processes, and environmental control, manufacturers can significantly reduce bubbling defects and improve the quality and stability of glove silicone heat transfer production.