Continuous vulcanisation

Continuous vulcanisation combines extrusion and vulcanisation in one continuous process, producing products of consistent quality. The key process consists of several steps:

Process steps of continuous vulcanisation

• Extrusion: the elastomer compound is extruded through a die in a continuous line to create the desired shape (e.g. profiles or hoses).

• Vulcanisation: the extruded material passes through a vulcanisation unit (e.g. hot air, microwave or liquid salt bath), in which the polymer chains are crosslinked.

• Cooling: after vulcanisation, the material is stabilised in a cooling tunnel.

• Processing: the product is either cut to length, wound up or, for special applications such as O-rings, processed into closed shapes.

For O-rings, continuous vulcanisation is combined with additional manufacturing steps. First, the material is continuously extruded and vulcanised to produce a uniform cord. The cord is then cut and the ends joined by butt vulcanisation or hot pressing. This approach ensures that the O-ring closes seamlessly and has optimum mechanical properties.

• Seamless products: elimination of joints, which increases tightness and durability.

• High production speed: the continuous process enables efficient production of large quantities.

• Consistent quality: uniform vulcanisation ensures consistent material properties.

• Flexibility: suitable for a wide range of products such as hoses, seals, profiles and conveyor belts.

Automotive industry

Continuous vulcanisation is used to manufacture door and window protection profiles, seals and hoses. These products must be seamless and extremely durable to meet the demands placed on vehicles.

Construction industry

In construction, continuously vulcanised seals and profiles are used for window frames, façades and doors. Continuous production makes weather- and UV-resistant products possible.

Industrial production

Conveyor belts, technical profiles and special seals made from continuously vulcanised elastomers are used in heavy industry, food production and chemical plants.

Vulcanisation is the decisive process for turning elastomer compounds into functional products. The following technologies are used in continuous vulcanisation:

Process	Description	Advantages	Typical applications
Hot air vulcanisation	The material is vulcanised in a hot air oven.	Cost-effective and suitable for simple profiles.	Seals, simple profiles.
Microwave vulcanisation	Microwave energy is used for fast and uniform vulcanisation.	High efficiency and fast production.	Hoses, technical profiles.
Liquid salt bath vulcanisation	The material is immersed in a heated salt bath.	Precise control of the vulcanisation temperature.	Complex technical profiles.
Infrared vulcanisation	Heat is transferred by infrared radiation.	Uniform heat distribution and energy efficiency.	Rubber and silicone profiles.

• Process control: precise control of temperature, speed and pressure is required to ensure consistent quality.

• Material requirements: the elastomer compound must be specially designed for the continuous vulcanisation process.

• Machine costs: purchasing and maintaining vulcanisation units is costly.

Feature	Continuous vulcanisation	Batch vulcanisation
Process	Continuous	Discontinuous
Production speed	High	Low
Product quality	Consistent	Variable
Initial costs	High	Medium
Typical applications	Profiles, hoses	Moulded parts, smaller series

• Which materials are suitable for continuous vulcanisation? Commonly used materials are EPDM, silicone, CR and NBR.

• Can continuous vulcanisation be used for O-rings? Yes, endless O-rings can be produced using additional processes such as butt vulcanisation.

• Which industries benefit from continuous vulcanisation? The automotive, construction and chemical industries benefit from the seamless products and high production speed.

• Is continuous vulcanisation energy-efficient? Yes, processes such as microwave or infrared vulcanisation in particular offer high energy efficiency.

Continuous vulcanisation is an essential process for manufacturing durable, seamless elastomer products. Thanks to its versatility and efficiency, it enables the production of high-quality profiles, hoses and seals for numerous applications. For O-rings in particular, it combines continuous processes with specialised manufacturing technology and is a key technology in modern elastomer production.