Butt vulcanisation

Butt vulcanisation is based on the chemical crosslinking of polymer chains using heat, pressure and vulcanising agents such as sulphur or peroxides. The material ends are precisely matched and vulcanised under specific conditions to achieve a seamless joint.

Steps in the butt vulcanisation process

• Preparation: the material ends to be joined are cleaned, cut to size and, if necessary, treated with vulcanisation aids such as bonding agents or adhesives.

• Positioning: the material ends are aligned exactly to ensure an even joint.

• Vulcanisation: heat and pressure are applied to initiate the chemical crosslinking of the polymer chains.

• Cooling: after vulcanisation, the product is cooled in a controlled way to fix the joint.

Butt vulcanisation produces joints with specific properties:

• High strength: the joint withstands mechanical loads and has high abrasion resistance.

• Seamless surface: minimises weak points and ensures a homogeneous material structure.

• Resistance: resistant to chemical, thermal and mechanical influences.

Butt vulcanisation offers a range of advantages:

• Robust joints: ideal for endless products with high load requirements.

• Flexibility: applicable to various types of elastomer and products.

• Efficiency: reduces material waste and enables cost-effective production.

Despite its advantages, there are also challenges:

• Precision: exact positioning of the material ends is crucial for the quality of the joint.

• Process control: temperature, pressure and time must be precisely controlled.

• Material compatibility: not all elastomers are equally suitable for butt vulcanisation.

Butt vulcanisation is used in numerous industries and products:

Conveyor technology

• Conveyor belts: production of endless belts for industrial use.

• Drive belts: joints that withstand high loads and continuous operation.

Sealing industry

• O-rings: precise joints for heavy-duty, tight products.

• Sealing profiles: production of seamless seals for windows, doors and machines.

Hose and pipe production

• Rubber hoses: joining end pieces to form seamless endless hoses.

• Industrial hoses: applications in the chemical, automotive and construction industries.

Butt vulcanisation differs from bonded joints in several respects:

Property	Butt vulcanisation	Bonded joint
Strength	Very high	Medium to high
Durability	Long-lasting	Depends on adhesive and ambient conditions
Temperature resistance	High	Limited
Surface	Seamless	Visible adhesive joint
Costs	Higher	Lower

• Which materials are suitable for butt vulcanisation? Elastomers such as NR, SBR, EPDM and NBR are ideally suited to this process.

• How long does the butt vulcanisation process take? The time depends on the material, temperature and pressure, but is typically between 10 and 60 minutes.

• Is butt vulcanisation more expensive than other processes? It can be more costly, but offers superior joint quality and longevity.

• Which machines are used for butt vulcanisation? Special vulcanising presses and heating plates are used.

Butt vulcanisation is an indispensable process in the rubber industry that enables high-quality joints for endless products. It combines strength, durability and precision, making it ideal for demanding industrial applications. Despite its challenges, it remains a preferred process for manufacturing durable, resilient products.