The topic of which glue is best for rubber adhesion is a difficult one to answer. Rubber comes in a variety of shapes and sizes, and it’s employed in a wide range of applications. Furthermore, it may cling to a variety of substrates in various applications, including hard to flexible, metal to plastic, and even another rubber. That’s why we at apelusa.com decided to put our heads together to compile a list of all the general guidelines of dealing with rubber so you can choose the best glue for rubber adhesion that will fulfill the majority of your needs.
Rubber Adhesion Rules in General
Identifying Your Rubber Type
Rubber comes in a variety of forms. It’s helpful to know which sort you’re trying to stick to so you know how much flexibility and hold you’ll need. The following are the most typical types of rubber you’ll try to bond:
- Nitrile rubber is a common rubber used in hoses, o-rings, gaskets, conveyor belts, cable jacketing, and print rollers, among other things.
- Butyl rubber is utilized in a variety of applications, including linings, inner tubes, seals and stoppers, and valve seats.
- Molds and modeling are made of polyurethane rubber.
- Mountings, carpet backing, gaskets, and seals can all be made of natural rubber.
- Silicone rubber is a common material for o-rings, gaskets, cookware, ovenware, medical devices, and prostheses because of its great heat resistance.
- EPDM rubber is used in automobile hoses, seals, and other applications.
Rubber Adhesion Preparation
Your rubber may have mold release, slip additives, or other lubricants on it by the time you’re trying to bond it due to its many usage. So, regardless of the rubber you’re working with, degrease it using a solvent before trying any adhesion.
Because acetone can be too harsh for some types of rubber, opt for isopropanol. Keep in mind that your rubber may contain a plasticizer that may eventually find its way to the surface and jeopardize your bond. That’s why it’s critical to try to identify your rubber and pair it with the appropriate adhesive!
Choosing the Best Adhesion Glue for Your Rubber
Adhesive made with cyanoacrylate
When it comes to gluing rubber, cyanoacrylate, commonly known as “crazy glue” or “super glue,” is an excellent place to start because it can adhere to a variety of substrates. Cyanoacrylate glue is an acrylic resin with cyanoacrylate as the major constituent, which is an acrylic monomer that cures to a plastic state. While moisture is required for cure, the connection will become extremely strong and hard nearly quickly.
While this is fantastic for fast assembly line settings, it may be a problem if your project takes a longer setup time to alter your substrates or if you need any flexibility at all. Due to its short open time, cyanoacrylate has a maximum gap fill of 0.5mm and cannot be utilized in a sprayer or roll coater for wide areas. On our blog, What Is Cyanoacrylate Glue?, you may learn how to use super glue correctly.
If your joint isn’t sticking, it’s possible that your rubber is EPDM or natural. We propose a cyanoacrylate made specifically for “challenging” rubbers for these surfaces.
Adhesive Made of Silicone
Silicone-based adhesives can be created to connect silicone rubber in a range of applications, from the home to transportation to outer space, thanks to elastomeric technology. Even after curing, silicone-based adhesives can be quite flexible, and they can survive extremely high temperatures, chemicals, and dampness. Depending on your demands, different formulations can even provide electrical insulation or conductivity.
While mixing is required with a two-component system, it can cure in thicker portions than one-part systems, which may be important for some applications. UV- or radiation-cured silicone adhesives cure without extra heating or excessive heat output using UV lamps or an electron beam.
Silicone adhesive systems with only one component require no mixing and cure at ambient temperature. The inclusion of a curing agent is required for two-component silicone adhesive systems, however they can cure in thick layers, which is necessary in some cases. For surfaces that are susceptible to extreme heat or contact pressure, silicone adhesive solutions that cure with UV light or an electron beam are ideal.
Keep in mind that due to its slick nature, silicone rubber may necessitate extra caution when bonding. Look for a primer to increase surface friction before applying an adhesive if your bond isn’t holding. At apelusa.com, you’ll find a large assortment of silicone and silicone-based adhesives.
Structural Acrylics in Two Parts
Difficult plastics like polypropylene, polyethylene, and PTFE are frequently bonded with two-part structural acrylics. Because EPDM rubber contains polypropylene, a two-part structural acrylic should adhere effectively to this similarly “tough” rubber substrate. While two-part acrylics require mixing to activate, they are more shelf stable than one-part acrylics, allowing them to be purchased in bulk and stored for extended durations.
Another advantage is that they cure more slowly than cyanoacrylates, allowing for re-alignment and spreading over a larger area. Some kinds are also resistant to extreme situations, even being completely submerged in water. While two-part structural acrylics are more difficult to apply than super glue, they’re worth it if you’re working with a problematic rubber like EPDM.
