A sticky surface on silicone parts can affect their feel, assembly, and appearance. Troubleshooting should address material migration, the curing state, surface treatment, and storage conditions, rather than relying solely on wiping.
1. Distinguishing Between Types of Stickiness
The root causes of initial stickiness and stickiness that develops after storage are different; you should first record the time and location when it occurs.
- Confirm whether it is concentrated on thick-walled areas, contact surfaces, or sprayed surfaces
- Check for any accompanying odors, exudates, or discoloration
- Comparison of Samples from Different Batches and Different Process Stages
2. Materials and Vulcanization
The compound formulation, the ratio of vulcanizing agents, and the actual heating conditions all affect the surface condition.
- Verify the rubber compound's shelf life and the uniformity of the mix
- Check the adequacy of vulcanization in areas of varying thickness
- Evaluate the improvement in volatile residue resulting from secondary vulcanization, if necessary
3. Surface Treatment and Contamination
An unusual texture may be caused by oil residue, release agents, or migration from packaging materials.
- Confirm the amount of release agent to use and the cleaning method
- Check the Spray Coating Curing Conditions and Adhesion
- Avoid prolonged direct contact with materials containing plasticizers
4. Improve Validation
After the adjustment, accelerated storage and exposure tests should be conducted to confirm that the problem does not recur.
- Compare surface friction, appearance, and odor
- Perform high-temperature storage and retest after exposure to heat and humidity
- Retain nonconforming items for root cause analysis
FAQ
1. Can alcohol be used directly to fix stickiness?
Cleaning can only remove surface residues; if the root cause is sulfidation or material migration, the problem will recur.
2. Will secondary vulcanization definitely eliminate stickiness?
Depending on the formulation and specific circumstances, this should be confirmed through comparative trials and should not be relied upon as the sole measure.