When walking into daily chemical warehouses, many product manufacturers encounter a common trouble: stored tinplate cleaning aerosol cans gradually develop liquid leakage. Sticky residues cover the can surfaces and pollute warehouse shelves. Such issues rarely stem from defective can production. Instead, ammonia ingredients inside cleaning formulas slowly erode internal sealing structures and lead to component failure. In fact, most manufacturers focus too much on can craftsmanship while overlooking the alkali aging resistance of aerosol rubber gaskets, which makes leakage risks exist throughout production, storage and sales.
1. Ammonia Erosion: The Core Cause of Damaged Aerosol Sealing Systems
1.1 Leakage Phenomenon in Full Distribution Channels
Cleaning aerosol cans usually stay in circulation for several months. Cans filled with ammonia-based cleaning solutions show no obvious defects in the first two months of storage. However, leakage problems break out intensively in the third month. Some cans leak slowly, while others suffer severe leakage at valve ports. This not only causes product loss, but also triggers consumer complaints and damages brand reputation after products reach the market.
Is there an effective way to avoid hidden dangers from the source? To solve the problem fundamentally, we need to figure out how ammonia damages sealing parts, rather than simply replacing accessories.
1.2 Chemical Reaction Mechanism of Ammonia
As a weak alkaline medium, ammonia will not swell rubber like organic solvents, yet it continuously changes the molecular structure of standard nitrile rubber. Rubber relies on flexible molecular chains to achieve sealing performance. Ammonia breaks the connections between molecular chains step by step and deprives rubber gaskets of ductility. Finally, NBR gasket hardening failure becomes unavoidable.
Latest accelerated aging test data shows that for cans equipped with standard NBR gaskets, the leakage rate will far exceed industrial standards after 90 days of storage under normal temperature and humidity. If the warehouse has poor ventilation and high temperature, chemical reactions speed up obviously, and the hardening cycle of sealing parts is nearly halved. As gasket hardness rises, gaps between valve cups and can crimps expand gradually. High-pressure propellant inside cans leaks continuously through tiny gaps, resulting in visible liquid leakage eventually. The whole failure chain is closely linked, and every minor change will aggravate product loss.
2. Two Main Seal Failure Modes: Essential Differences Between Hardening and Swelling
Rubber gaskets mainly suffer from two types of failure in chemical media. Many practitioners confuse the two modes and make wrong choices in material selection.
Swelling usually occurs in oil and aromatic hydrocarbon environments. Rubber absorbs external media, expands and softens. Deformation and dislocation of sealing surfaces then cause leakage. This problem can be improved by adjusting rubber formulas or controlling medium concentration.
Failure caused by ammonia is totally different. Ammonia does not expand rubber volume. It triggers chemical cross-linking reactions and makes rubber molecular chains lose flexibility. Elastic rubber gradually turns into rigid plastic. This kind of damage is irreversible. Once gaskets start to harden, they can never recover original sealing performance even after being moved out of ammonia environment. In most cases, ammonia-based cleaning formulas barely cause swelling, so hardening is the key risk to prevent.
3. Comprehensive Evaluation of Main Ammonia-resistant Sealing Materials
Four types of sealing materials are widely used for ammonia-related cleaning aerosols. Combining material characteristics, actual test data, compliance requirements and long-term application experience of SAILON in supporting tinplate cleaning aerosol cans, we compile a detailed comparison table for efficient material selection.
| Material | Ammonia Resistance Rating | Aging Resistance | Applicable Temperature Range | Deformation Rate | Compliance Certification | Suitable Ammonia Concentration Scenarios |
|---|---|---|---|---|---|---|
| Standard NBR | Poor | Average | -20℃~80℃ | Fast hardening | Basic General Certification | Ultra-low ammonia concentration, short-term turnover products |
| EPDM | Good | Excellent (Ozone & Moisture Resistance) | -40℃~120℃ | Slight deformation | General Contact Certification | Low ammonia concentration, conventional storage |
| HNBR | Outstanding | Good (High-temperature Aging Resistance) | -30℃~110℃ | Controllable deformation | Full-range Daily Chemical Certification | Medium & high ammonia concentration, closed high-temperature warehouse |
| PTFE Composite | Premium | Permanent anti-aging | -60℃~200℃ | Nearly no deformation | Food & Daily Chemical Dual Certification | High ammonia concentration, long shelf life, high-end cleaning formulas |
Based on the table above, here is the material selection guide for different formulas:
- Ammonia concentration below 3% and product turnover cycle less than 2 months: EPDM is the best choice with balanced cost and performance;
- Ammonia concentration between 3% and 8% and high temperature in warehouse in summer: HNBR is recommended to meet the requirements of aerosol long-term storage sealing stability;
- Ammonia concentration above 8%, long shelf life requirement or food-related cleaning scenarios: PTFE composite gaskets provide full protection;
- Standard NBR is not recommended for cans with ammonia formulas for long-term storage.
4. Standard Testing: Verify Sealing Reliability with Professional Methods
Visual inspection alone cannot predict seal failure after several months. A complete testing procedure is essential for quality control. The aerosol pressure decay test is the most recognized core testing method in the industry. Combined with auxiliary tests, it can fully evaluate sealing performance.
4.1 Advantages and Disadvantages of Three Main Leak Detection Methods
- Water bath visual inspection: Easy to operate, only detects obvious large-gap leakage, suitable for preliminary factory inspection;
- Pressure decay method: Monitors internal air pressure continuously, accurately captures tiny leakage, the core test for long-term sealing performance evaluation;
- Helium mass spectrometry leak detection: Highest detection accuracy, locates micron-level gaps, widely used for high-end products and harsh working conditions.
4.2 Accelerated Aging and Simulated Storage Test Procedures
In accordance with ISO 14644-3:2019 standards, complete verification includes two stages. The first stage is high temperature and high humidity accelerated aging test, which simulates extreme storage conditions to quickly check alkali resistance and aging resistance of gaskets. The second stage is real-scenario storage test. Finished cans are placed in conventional warehouses, and air pressure & leakage conditions are tracked for months.
When customizing tinplate cleaning aerosol cans, SAILON provides complete test reports for every batch of products. Seal performance tests are integrated into quality control to eliminate potential risks in advance. General industrial qualification standards require that the internal pressure drop of finished cans shall not exceed 2.2% within 30 days, and the leakage rate shall be lower than 0.3% after 90-day accelerated aging test.
5. Practical Case: Batch Problems Caused by Mismatched Formulas and Seals
A household cleaning brand once used standard NBR gaskets to match ammonia-based glass cleaner. Production and delivery ran smoothly at the beginning. However, after the whole batch was stored in conventional warehouses for three months, nearly 30% of cans suffered leakage. It caused product loss and disrupted the overall supply schedule.
After investigation, the technical team confirmed that continuous erosion from ammonia led to gasket hardening. Later, the brand replaced NBR with HNBR gaskets according to formula concentration and optimized warehouse temperature and humidity management. After adjustment, continuous tracking tests for twelve months showed zero leakage for the whole batch, and product loss was completely eliminated.
This case proves that cans, valves, gaskets and formulas form an integrated system. Qualified single component is far from enough. The matching performance of all accessories determines product stability. Many enterprises focus on can manufacturing, while ignoring small gaskets, which often become the weakness of quality control.
6. Practical Suggestions for Procurement and Quality Control
To avoid seal failure from the source, proper material selection is not enough. We also need to standardize procurement and daily quality control work. Key points are listed as follows:
- Verify supplier qualifications: Confirm suppliers hold complete quality system certifications and can provide chemical composition descriptions and past application cases of sealing materials;
- Ensure batch consistency: Require original test data of hardness and deformation rate for every batch of gaskets, and forbid arbitrary raw material replacement;
- Specify testing clauses in cooperation agreements: Require suppliers to provide data of accelerated aging tests and pressure decay tests to guarantee consistent performance of each batch;
- Arrange trial production: Carry out small-batch trial production and full-cycle tests before mass production when updating formulas or replacing sealing materials.
7. Frequently Asked Questions (FAQ)
Q1: The ammonia concentration of my cleaning formula is about 2.5%, and the warehouse keeps good ventilation. Do I need to replace original NBR gaskets?
A: Original accessories are acceptable for short-term turnover. But if products need to be stored for more than three months, switching to EPDM will greatly reduce the risk of gasket hardening.
Q2: Can thicker plates of tinplate cleaning aerosol cans solve leakage caused by ammonia?
A: The answer is no. Leakage results from failed valve seals. Thicker can plates only resist extrusion and deformation, and have no connection with sealing performance.
Q3: Why do some cans leak severely while others stay intact with the same batch of gaskets?
A: It is usually caused by slight differences in raw materials or inconsistent crimping precision. It is suggested to strictly control crimping parameters and require suppliers to ensure batch stability of gaskets.
Q4: Is it necessary to conduct regular sampling inspection for stored products after factory inspection?
A: Yes. Factory inspection only reflects the real-time status. Temperature, humidity and chemical erosion during long-term storage will change sealing performance. Regular sampling can detect hidden dangers in time.