What are the requirements for the technical specifications of drum rubber coating?

The quality of roller rubber coating is determined by both the coating material and the coating construction technology. Even with the same material, different construction parties will result in varying quality of roller rubber coating. Besides their own construction qualifications, it also depends on whether the technical specifications for roller rubber coating are strictly followed.
Cold vulcanization roller rubberizing is an internationally leading roller rubberizing technology. The cold vulcanized roller rubberizing, which is made using CVUL wear-resistant rubber sheets with a semi-vulcanized layer, cleaning agents, CVUL metal treatment agents, cold vulcanization adhesive CV2000, and rubber repair agents, can achieve the final bonding strength of hot vulcanization, and its service life is 8-10 times that of hot vulcanized rubberizing. However, some construction companies have encountered situations where the rubber sheets delaminate shortly after rubberizing.
Cold vulcanization adhesive, metal treatment agent, cleaning agent, roller rubber coating material
Next, we will elaborate step by step on the requirements of the technical specifications for roller rubberizing. In the actual operation process, it is necessary to strictly follow these specifications to avoid various situations that may arise after the roller is rubberized.
Polishing
Grinding is a process of derusting, leveling, and cleaning the surface of the roller. Properly deep grinding can increase the bonding area and improve the bonding strength while ensuring overall flatness. Good grinding of the roller is the foundation for roller rubber coating and bonding. The grinding depth is 30μm. If the depth is difficult to grasp, visually, grind the roller until the metal color is exposed and then slightly deeper.
For some conveyor belt drums with very high tension, it may also be necessary to perform sandblasting on the polished drums to further increase the roughness of the drum surface and enhance the adhesive force.
Cleaning
Clean the surface of the drum
The purpose of cleaning is to ensure the cleanliness of the roller surface, preparing it for the next step of applying metal treatment agent. Use cleaning agent SK353 to thoroughly clean the polished surface of the roller for 1-2 times, removing any impurities such as grease, oil stains, dust, and other substances that may affect the bonding strength.
Apply primer
CVUL metal treatment agent, also known as metal primer, provides a strong adhesive bond with glue to difficult-to-stick smooth metal surfaces. The metal treatment agent itself does not possess adhesive strength. Metal treatment agent is an important guarantee for preventing glue failure and debonding of the rubberized board after roller rubberization. Many times, the insufficient bonding strength of roller rubberization is due to uneven application, excessive or insufficient thickness of the metal treatment agent. Not using metal treatment agent is even more irresponsible towards the project.
Glue mixing
Before using the cold vulcanization adhesive CV2000, the glue and curing agent must be fully mixed in a ratio of 100:4. The adhesive strength and tensile strength of the mixed glue are significantly enhanced, and the curing time is greatly shortened. 1kg of glue can be applied to cover an area of about 1 square meter. The unmixed part should be sealed and placed in a cool and dry place.
The mixed glue will lose its effectiveness after 1 hour, and high temperatures will accelerate this process.
Glue application
Apply cold vulcanization adhesive CV2000 to the surface of the drum
The roller should be coated with glue at least three times, twice on the roller surface and once on the semi-vulcanized layer of the rubber plate. After the metal treatment agent is thoroughly dried, apply the first coat of glue, and wait for it to fully dry. Then, apply the second coat of glue when it is semi-dry (i.e., has adhesive strength but does not adhere to the back of a finger). Finally, proceed with the bonding process.
The semi-vulcanized layer of the rubber sheet can undergo a vulcanization reaction and integrate with the cold vulcanizing adhesive CV2000. Without grinding, only one layer of adhesive is needed, and applying too thick a layer is meaningless. For rubber sheets without a semi-vulcanized layer, the bonding surface of the sheet needs to be ground, roughened, and cleaned before applying adhesive, which should also be done in two coats.
The application of glue must be even, as uneven application or excessive thickness of the glue layer in certain areas can reduce the adhesive strength.
The curing process of cold vulcanization adhesive CV2000 is an endothermic process, during which the surface temperature of the adhesive layer decreases. In low-temperature and humid environments, it is prone to condensation, which can affect the curing process and reduce the bonding performance. Therefore, when working in underground environments or other high-humidity settings, it is necessary to use heating devices such as iodine-tungsten lamps or heaters to dry and heat the adhesive, ensuring rapid curing.
If the glue is found to be too dry during the bonding process, a layer of glue should be applied again before bonding.
Rubber plate bonding
During the process of adhering the rubber plate, it should be gradually advanced, with a compaction roller rolling back and forth to eliminate bubbles within the bonding surface. Subsequently, a rubber hammer should be used to press it down firmly, ensuring that the rubber plate is fully adhered to the roller.
The cold vulcanization adhesive CV2000 boasts strong initial adhesion, which means it can immediately achieve a sufficiently strong bonding force once applied, thus eliminating the need for prolonged pressure.
It is ideal to complete the rubber coating with a single intact rubber sheet. For some drums, it may be necessary to use multiple rubber sheets for the coating process, but the number of sheets used for splicing should not exceed three. The splicing should be done with horizontal seams, and vertical splicing of rubber sheets is not allowed.
Gap treatment
Depending on the process, gaps may remain at the seams of the rubber plate. These gaps need to be filled with rubber repair agent CV2000. After filling, the rubber plate exhibits stronger integrity and better stress resistance. Additionally, it prevents erosion of the bonding surface of the rubber coating and the roller, extending the service life of the roller's rubber coating.
The drum rubberization is strictly carried out in accordance with technical specifications, and certain targeted treatments are implemented in harsh environments. It is entirely possible to obtain high-strength drum rubberization.