Proper cleaning of the silicone tubing can ensure product quality, thereby enhancing your brand reputation and reducing production costs. So, we will provide you with professional guidance on industrial-grade cleaning methods and the mistakes to avoid during the cleaning process.
Why Does Silicone Tubing Need Regular Cleaning?
Silicone tubing possesses excellent heat resistance, chemical resistance and UV protection properties, and is applied in various industries. Moreover, the surface of silicone tubing has natural hydrophobicity. However, if you think that silicone tubes can resist all contaminants, you are completely wrong.
If you do not regularly clean the silicone tubing used in your production process, even the highest-quality silicone tubing will still have contaminants remaining inside and allow bacteria to grow, which will affect the quality of your products.
Proper cleaning not only can extend the service life of your silicone tubing and reduce costs, but also is a basic requirement for compliant production.
4 Industrial-Grade Cleaning Methods
Cleaning In Place (CIP)
When you are engaged in the food processing, pharmaceutical or biotechnology industries and use silicone tubes, CIP is an efficient and convenient option. Because this method can complete the cleaning without disassembly, it not only improves your cleaning efficiency, but also does not damage the silicone tubing and can be adapted for large-scale continuous production.
However, you should be aware that if the cleaning system is incompatible with the silicone tubing, it may cause the tube to be damaged or result in incomplete cleaning.
Cleaning Steps
First, you need to check the compatibility between the silicone tubing and the cleaning system to ensure they match. Then, start moistening the silicone tubing that needs to be cleaned.
Prepare the cleaning solution and set the cleaning parameters. For example, you can control the temperature of the cleaning solution within 40-60℃, keep the flow rate at 1.5-2.5 m/s, and adjust the cleaning time to 15-30 minutes according to the degree of contamination.
Inject the cleaning solution into the circulation system. After the equipment is started, allow the cleaning solution to circulate within the silicone tube. Don’t forget to regularly monitor the temperature and flow rate. After the circulation is complete, rinse with deionized water until no cleaning solution remains.
High-pressure Water Rinsing
If you are involved in the cosmetics or chemical industry, you will find that there are impurities remaining inside the silicone tubes. High-pressure water rinsing is the preferred method for removing large particles of impurities inside the tubes. This method is simple to operate and has a good effect in removing impurities.
Cleaning Steps
To prevent chemical reactions, we recommend that you use deionized water for rinsing. First, close the valves at both ends of the silica gel tube, and insert the high-pressure water gun into the opening at one end. You can adjust the water pressure to 5 bar to ensure uniform pressure and avoid damaging the pipeline.
After turning on the water gun, keep rinsing for 5 to 10 minutes. It’s best for you to constantly adjust the angle of the water gun during the rinsing process, so as to ensure that all parts of the inner wall of the pipe can be thoroughly washed.
If you find large stubborn particles that cannot be removed by a single rinse, you can repeat the rinsing process 2-3 times. After the rinsing is completed, promptly sterilize the silicone tube to prevent bacteria from growing due to residual moisture.
Soaking and Circulation Cleaning
If your production scale is small or you need to clean small quantities of silicone tubes, soaking and circulation cleaning is the easiest way to do it. Because this cleaning method doesn’t require complex equipment and is simple to operate with low costs.
Cleaning Steps
First, choose the appropriate cleaner. We recommend using a neutral cleaner or 70% IPA (Isopropyl Alcohol). Remove the silicone tube and place it in the container filled with the cleaning agent, leaving it to soak for 20 to 30 minutes.
If you want to completely dissolve the stains, gently oscillate the container during the soaking process to ensure that the cleaning agent can fully come into contact with the inner walls of the tube. After the soaking is complete, connect the silicone tube to the simple circulation device and use the cleaning agent to rinse it in a circular motion for 10 to 15 minutes.
Finally, rinse thoroughly with deionized water until no cleaning agent or IPA remains. However, you should be aware that the rinsing process must be thorough; any remaining cleaning agent or IPA could cause contamination of the product.
High-Temperature and High-Pressure (HTHP) Sterilization
When you are in industries such as pharmaceuticals that have strict requirements for the working environment and need to ensure sterility, silicone tubes also need to be thoroughly sterilized. HTHP sterilization is the most reliable method to meet your needs and can achieve complete sterilization.
However, if you frequently perform high-temperature and high-pressure sterilization, it will accelerate the aging of the silicone tube and shorten its service life. Therefore, we recommend that you reasonably arrange the number of sterilizations according to the actual usage frequency.
Cleaning Steps
Before placing the silicone tubes neatly into the sterilization pot, you need to clean and dry them thoroughly, and set the key parameters. We recommend that you use the following parameters: temperature 121℃, pressure 15psi, and sterilization time 30 minutes.
Then turn off the sterilization pot and start the equipment. After the sterilization process is completed, you need to slowly release the pressure; otherwise, dangerous incidents may occur. After the temperature drops to room temperature, remove the silicone tube and store it sealed.
Standards for Silicone Tubing Cleaning Validation
If you want to ensure the safety and reliability of the silicone tube cleaning process, you can refer to the following international standards for inspection.
| Category | Standard / Regulation | Scope of Application |
| Pharmaceutical Compliance | USP <87>, USP <88>, FDA 21 CFR 177.2600 | Biocompatibility and material safety |
| Food Industry Compliance | EC 1935/2004, FDA 21 CFR 177.2600 | Compliance of food contact materials |
| General Cleaning Validation | USP <643>, ASTM D7579 | Cleaning residue testing by TOC method |
| Cleanroom Standards | ISO 14644 (series) | Post-cleaning treatment and storage environment |
5 Mistakes to Avoid When Cleaning Silicone Tubing
Using Incompatible Chemicals
Strong solvents such as ketones, toluene, highly concentrated strong acids or strong bases can cause your silicone tubing to swell severely, become sticky, and even degrade, which may lead to the failure of production equipment.
When cleaning ordinary silicone tubes, you should also avoid using high-concentration bleach, as it can cause the silicone to age. While ordinary silicone tubes may absorb synthetic oil-based detergents, they will later seep out and contaminate the products. If you notice that the silicone tubing has been damaged by chemical solvents, you must replace it immediately.
Overexertion and Improper Tool Use
If you use abrasive polishing agents or hard brushes to rub repeatedly with force, fine scratches will be formed on the surface of the silicone tubing, which will lead to the growth of bacteria. Especially when you are in the dairy industry, a significant decline in tubes’ cleanliness can lead to the spoilage of beverages.
Similarly, excessive twisting, excessive stretching, and vigorous pounding can all cause damage to the silicone tubing, resulting in deformation.
Inadequate Rinsing
When you choose an effective detergent to clean the silicone tubing, the cleaning process is actually only half complete. If you don’t thoroughly rinse it with pure water multiple times, the cleaning agent may remain in the silicone tubing.
If you are involved in the pharmaceutical industry, silicone tubing usually requires 3 to 5 rounds of rinsing. For the last rinse, we recommend using water of higher purity, such as purified water, for final cleaning. You can use pH test paper or specialized testing agents to confirm if there are any cleaning agent residues after the rinsing process.
Ignoring High Temperature Effects
Although silicone tubing can withstand high temperatures, they will still age if exposed to excessive temperatures for a long time. Because after steam sterilization, you need to drain the water vapor from the tube material, and the combined effects of rapid cooling and high pressure accelerate the aging process of the silicone tubing.
Especially, during the sterilization process, you failed to keep one end open, which blocked the air flow exchange and created a high-pressure environment inside the silicone tubing.
One-Size-Fits-All Cleaning Solution
Different application fields have their own specific cleaning procedures, post-cleaning inspection standards, and replacement cycles for silicone tubing. If you use a uniform cleaning method, it will cause the equipment to malfunction.
No matter which field you are in, if it involves critical materials, it is necessary to conduct verification of total organic carbon and conductivity on the residues after processing.
If you want to ensure the reliability of the operation, after each cleaning of the silicone tubing, personnel should be arranged to conduct a visual inspection and require them to record the cleaning execution information.
FAQ
Can Ultrasonic Cleaners Be Used to Clean Silicone Tubing?
Yes, but we suggest you use it with caution. Because ultrasonic cleaners can remove tiny particles on the inner wall of the silicone tubing, but if you use it for a long time or at a high power, it may cause damage to the interface.
Is Complete Drying Mandatory Before HTHP Sterilization of Silicone Tubing?
It is recommended that you perform a moderate drying process, as residual water droplets can affect the sterilization effect. It can be decided according to your actual needs. If you use it immediately after sterilization, there is no need to dry it; if you need to store it for future use after sterilization, it must be completely dried.
What Are the Residue Testing Standards for Silicone Tubing After Cleaning?
When you check for residual contamination in the silicone tubing, you can refer to the following standards:
Whether the change in conductivity exceeds 0.5 µS/cm;
If you are in the pharmaceutical industry, whether the TOC is controlled within 0.5 mg/L.
For visual inspection, you must ensure that there are no visible residues on the surface.
If you are in the medical industry, you also conduct bacterial endotoxin testing.
Does the inner surface roughness of silicone tubing change after cleaning?
Yes. The inner wall roughness of a new silicone tube is usually between 0.2 and 0.5 μm. It increases with each cleaning. If you tilt the silicone tube towards the light and notice a frosted texture or rainbow patterns on it, then you should replace it.
Are there pretreatment methods to avoid residue adsorption on silicone tubing during cleaning?
Yes. You can soak the silicone tubing in 0.1% non-ionic surfactant for 4 hours. After rinsing thoroughly, it can reduce the adsorption of protein or oil-based dirt.
Final Thoughts
Legensilico is a silicone manufacturer in China with over 20 years of manufacturing experience and possesses extensive knowledge in silicone. If you want to learn more about silicone products and knowledge, please feel free to contact us at any time.
