Surface Preparation for Rubbers
Master Bond manufactures a wide range of adhesives for bonding rubbers to rubbers, as well as rubbers to other substrates. Surface preparation plays a key role in ensuring that good bond strength is achieved. The following techniques are typically used as practices for proper surface preparation.
Degreasing
Degreasing is carried out in order to remove any loosely held dirt or other contaminants from the surface. Surfaces can be degreased using volatile solvents such as toluene, acetone, methyl ethyl ketone, methyl alcohol, isopropyl alcohol, and trichloroethylene. Please make sure, however, that all the environmental, health, and safety regulations are met prior to selecting a solvent. The most common methods used typically include three main steps:
Vapor degrease/clean/rinse the parts with the appropriate solvents Immerse the substrates in a fresh bath of solvent for the wash and follow with an immersion in the second tank for a rinse Clean and dry the substrate post-degreasing
Abrasion
The surfaces need to be degreased and cleaned before as well as after abrasion to remove any pre-existing contaminants on the surface. Once the surfaces have been abraded, they need to be degreased to remove the debris from abrasion.
Depending on the exact rubber being used, the abrasion technique that is eventually employed might vary. Please note: caution must be exercised based on the exact material used regarding the feasibility of this technique.
Chemical Treatment
Specific chemical techniques have been developed for treating different substrates. These treatments change the physical as well as the chemical properties of the surface in order to improve adhesion. A wide range of acids and alkalis are used for this purpose. Typically the specific chemical or mixture of chemicals is placed in a chemically resistant container. The chemical bath is then heated to the appropriate temperature and the rubber is immersed in the chemical bath for the required amount of time.
After chemically treating the surfaces, it is important to rinse the surface with DI water and thoroughly dry the surface before it is subjected to further use. Extreme care, including good laboratory skills, should be used while handling these chemicals. Personnel should be wearing appropriate personal protective equipment and should be well trained in handling of these chemicals.
The three most common techniques used for surface treating rubber substrates are:
Trichloroethylene Solvent: Degrease the rubber substrate as mentioned above using trichloroethylene solvent. Modified Bleach Solution: Prepare the modified bleach solution by pouring cold DI water (1 liter) into a clean container made of plastics, glass, or similar inert ware. While stirring the water, add concentrated hydrochloric acid (5 ml) in a slow steady stream. Then add household bleach (30 ml), stirring it thoroughly into the diluted acid. Immerse the rubber substrate in modified bleach solution for 1 to 3 minutes at room temperature. Following that, rinse it in cold DI water, followed by a rinse in hot DI water. Finally, dry the substrate in hot air. Sulfuric Acid Solution: Immerse the rubber substrate in concentrated sulfuric acid for 2 to 10 minutes. Following that, rinse it in cold DI water, followed by a rinse in hot DI water. Finally, dry the substrate in hot air.
A combination of degreasing, abrasion, and chemical treatment techniques can be employed for preparing rubber surfaces.
