Rubber lining materials play a crucial role in protecting industrial tank equipment. By providing a resilient barrier against corrosion, abrasion, and chemical attacks, rubber linings extend the lifespan of these vessels, reducing maintenance costs and operational downtime.
When selecting the right rubber lining solution for your application, it’s essential to understand the properties, benefits, and limitations of the different materials available.
Cured vs. Uncured Rubber
There are two main types of rubber used to line tanks: cured and uncured. The difference between them primarily lies in their state of vulcanization, a chemical process by which the physical properties of the rubber are improved.
Cured rubber undergoes the vulcanization process before installation, while uncured rubber does not.
More on Vulcanization
Vulcanization typically involves mixing crude rubber with 5-30% sulfur or another similar agent to create cross-links between the polymer chains. Other additives like zinc oxide, thiurams, calcium chloride, amines, phenolics and phosphites, color pigments, oils, and anti-foaming agents may also be used in the process.
Some alternative vulcanization methods are peroxide vulcanization, which is used for rubbers incompatible with sulfur or that require high temperature resistance, and radiation vulcanization, which is used for specialized applications where chemical residues must be limited.
Vulcanized (or cured) rubber is used to make tires, conveyor belts, shoe soles, rubber hoses, erases, and of course rubber lining for tanks.
Cured Rubber Lining Materials For Tanks and Vessels
Because they’ve undergone the vulcanization process, cured rubber linings are typically more durable and elastic than uncured rubber linings.
Cured Rubber Lining Benefits
The benefits of using cured rubber to line tanks are:
- High durability: Vulcanization significantly enhances the rubber’s toughness, making it highly resistant to abrasion and impact.
- Chemical resistance: Cured rubber linings exhibit excellent resistance to a variety of chemicals, from acids to alkalis to solvents. For tanks storing aggressive substances, this ensures long-term protection.
- Temperature stability: Cured rubber linings maintain their integrity across a broad temperature range, making them suitable for applications in extreme heat or cold.
Cured Rubber Lining Limitations
However, cured rubber is not without its limitations. Some disadvantages of this material are:
- Installation complexity: Vulcanization requires precise temperature and pressure control, making installation more complex and time-consuming.
- Repair challenges: For similar reasons, repairs to cured rubber lining can be difficult, often requiring specialized techniques and equipment to ensure proper adhesion and integrity.
Uncured Rubber Lining Materials For Tanks and Vessels
Uncured rubber lining, also known as soft rubber lining, is applied in its raw, unvulcanized state. It is then vulcanized in place, typically with heat and pressure.
Uncured Rubber Lining Benefits
Why would you choose uncured rubber vs. cured rubber to line tanks? If you wanted to take advantage of any of these properties:
- Flexibility: Uncured rubber can conform closely to the contours of a tank or vessel, which is ideal when working with complex shapes and intricate installations.
- Ease of installation: Since this lining doesn’t require pre-vulcanization, it’s generally easier and quicker to install. If reduced labor costs and less operational downtime are important to you, this may be your preferred material.
- Repairability: Uncured rubber lining can be repaired more easily than cured rubber lining. Damaged sections can simply be removed and replaced with new uncured material, then vulcanized in place.
Uncured Rubber Lining Limitations
But uncured rubber lining also has its drawbacks:
- Lower initial strength: Before vulcanization, uncured rubber lining lacks strength and chemical resistance, so it could be susceptible to damage during installation.
- Vulcanization requirements: The need for on-site vulcanization can complicate the installation process, requiring specialized equipment and experienced technicians to ensure proper curing.
Rubber Coatings for Industrial Tank Applications
To enhance the performance of rubber linings even further, you can apply a range of industrial rubber coatings. These coatings provide additional layers of protection and improve the overall durability and efficiency of a lining system.
Popular Industrial Rubber Coatings
When selecting a rubber lining coating, it’s important to consider your unique application. Where is the tank or vessel located? What substance(s) will it store? What types of wear and abrasion will it most often be exposed to?
From there, you may choose one of these popular coating solutions:
Chemical-resistant Coatings
As the name suggests, chemical-resistant coatings are designed to withstand exposure to harsh chemicals, providing an extra barrier that prevents chemical degradation of the lining. If your tank will hold or be exposed to corrosive substances, this is likely your solution.
Epoxy and vinyl ester coatings are popular chemical-resistant coating choices.
Abrasion-resistant Coatings
Abrasion-resistant coatings combat mechanical wear and tear, such as scratches, impacts, and other forms of physical — not chemical — damage. This physical damage could be brought on by environmental factors, or by storing solid materials inside the tank.
Polyurethane and ceramic-filled coatings are popular choices in this coating category.
Thermal-resistant Coatings
Thermal-resistant coatings are key in applications involving extreme temperatures. They help maintain the integrity of the rubber lining by preventing thermal degradation from high heat or cold, which is typically caused by environmental factors but can also be due to substances stored.
Silicone and polytetrafluoroethylene (PTFE) are popular thermal-resistant rubber coatings.
Anti-microbial Coatings
Tanks used to store water or food products can experience microbial growth and bacterial or fungal contamination. Anti-microbial coatings incorporate silver ions, which have natural anti-microbial properties, to prevent this.
Putting It All Together: How to Select the Right Rubber Lining & Coating Combination
Choosing the appropriate rubber lining material and associated coatings for your specific needs requires careful consideration of various factors. Some key points to keep in mind are:
Evaluate Environmental Conditions
Think about the chemical exposure, mechanical wear, and temperature range in your application. These factors will be the main drivers in your choice of material and coating.
Assess Installation and Maintenance Needs
Consider the level of installation complexity (and costs associated with it) you can tolerate, plus the ease of future maintenance you’d prefer. Uncured rubber linings may offer advantages in terms of flexibility and repairability, while cured solutions will provide superior initial strength and durability, meaning they may not need to be repaired as often.
Consult with Experts
Whether you think you’ve found your answer or not, it’s important to consult an expert in the field. Working with experienced rubber lining technicians will ensure the best choice is made, resulting in the peak performance and longevity of your equipment. They may even bring up some points you hadn’t considered before!
Need an expert to talk to? Get in touch with our team at US RUBBER, with over 35 years of experience in multiple industrial sectors.
