Rubber adhesives play a crucial role in various industries. Whether it is firmly connecting rubber components to metal, plastic, or other rubber components to form functional components, rubber bonding is essential.
For example, in the automotive industry, rubber adhesives are crucial for manufacturing seals, gaskets, and shock absorbers. In industrial machinery, it ensures the durability of rollers and belts. Medical devices rely on adhesive rubber to manufacture flexible tubes or protective covers. Rubber adhesives are also commonly used in consumer goods such as footwear and electronics, as their durability and functionality are crucial. Whenever a product requires strength, flexibility, or environmental resistance, rubber bonding becomes a critical step in the manufacturing process.
Why is rubber type crucial for bonding?
Each type of rubber material has different characteristics, such as flexibility, chemical resistance, and surface energy, which can affect its compatibility with adhesives
Low surface energy: such as silicone and EPDM rubber, require the use of primer or specialized adhesive to ensure firm bonding.
Plasticizer migration: Rubber such as NBR, SBR, EPDM, etc. may release plasticizers over time, affecting long-term adhesion performance.
Environmental conditions: Some rubbers perform well in extreme temperatures or harsh environments, requiring adhesives to work under these conditions.
Surface treatment of rubber bonding
Proper surface treatment is crucial to ensure the firmness of rubber bonding. Rubber surfaces often adhere to contaminants such as release agents, slip additives, or lubricants, which can affect adhesion.
Cleaning the surface with solvents such as isopropanol can effectively remove these impurities, but it is important to avoid using corrosive solvents such as acetone, which may damage certain rubber.
To improve adhesion, surface energy can be increased by polishing the rubber surface or using plasma, chemical primer, and other methods, especially for low surface energy rubber such as silicone and EPDM.
Due to the migration of plasticizers in certain rubbers over time, it is recommended to use adhesives that are resistant to plasticizer migration. Before applying adhesive, ensure that the rubber surface is clean, dry, and treated to achieve a reliable and long-lasting bonding effect.
The best adhesive suitable for different rubbers
When choosing a suitable rubber adhesive, it is necessary to consider the type of rubber used. Common types of rubber include nitrile rubber (NBR), butyl rubber (IIR), polyurethane rubber (PUR), silicone rubber (SiR), ethylene propylene diene monomer (EPDM), and natural rubber (NR), which are widely used in products such as hoses, gaskets, seals, and inner tubes.
Cyanoacrylate adhesive (usually referred to as strong adhesive) is widely popular due to its rapid curing and strong adhesion, suitable for most rubber types such as natural rubber and NBR. When used in conjunction with specialized hard rubber adhesives, no primer is required, simplifying the bonding process. For certain specific materials, such as EPDM, there are also specialized cyanoacrylate adhesives on the market that do not require the use of a primer. However, the ability of cyanoacrylate adhesive to fill gaps is poor, its applicability is limited (usually less than 0.5 millimeters), and there is not much time to readjust after curing.
Silicone adhesive: designed specifically for bonding silicone rubber, it has excellent properties such as UV resistance, high temperature resistance, chemical resistance, and moisture resistance, as well as good flexibility and electrical insulation. It is commonly used in O-rings, seals, and electronic products.
Structural acrylic adhesive: suitable for bonding EPDM rubber. Due to its slow curing time, it can achieve precise alignment and spreading, making it suitable for applications that require precision assembly.
ELAPLUS recommended products
SIPC 1859 silicone adhesive sealant
SIPC 1859 silicone adhesive sealant SIPC 1859 alcohol free silicone adhesive sealant is a neutral silicone sealing material that absorbs moisture from the air and solidifies at room temperature. It is non corrosive to materials and has good adhesive and sealing properties for most plastic, metal, and other materials, protecting electronic products in a stable state under harsh conditions.
SIPC 1846 silicone adhesive sealant
SIPC 1846 silicone adhesive sealant is a neutral silicone sealing material that absorbs moisture from the air and solidifies at room temperature. This adhesive is made of specially modified silicone material. After the thin layer of adhesive is completely cured for 7 days, it can maintain elasticity at a high temperature of 250 ℃ without sticking or bubbling on the surface. Compared with other silicone systems, SIPC 1846 produces very little white mist in a closed environment.
SIPC 1856 silicone adhesive sealant
SIPC 1856 silicone adhesive sealant RTV 1856 silicone adhesive sealant is a neutral silicone sealing material that absorbs moisture from the air and solidifies at room temperature. It is non corrosive to materials and has good adhesive and sealing properties for most plastic, metal, and other materials, protecting electronic products in a stable state under harsh conditions.
Common rubber bonding problems and solutions
Weak adhesion: Check the surface for contaminants such as oil, release agent, or dirt. Confirm whether the amount of adhesive used is appropriate and whether the curing process is completed under the recommended conditions.
Adhesive failure: Ensure that the adhesive used is compatible with the type of rubber. Using unsuitable adhesives can lead to poor bonding or even complete failure. For certain rubbers such as silicone and EPDM, specialized adhesives or primers may be required.
Layering: If the bonding surface separates over time, it may be due to improper surface treatment. Please ensure that the surface has been thoroughly cleaned, roughened, or coated with primer before applying the adhesive to ensure a good bonding effect.
By understanding the characteristics of different types of rubber and suitable adhesives, and ensuring proper surface treatment, the effectiveness and durability of rubber bonding can be greatly improved. For more knowledge about adhesives, please continue to follow ELAPLUS.
Tags: Rubber Adhesive · Silicone Rubber Adhesive
