Metal oxide crosslinking

What is metal oxide crosslinking?

Metal oxide crosslinking is a special process for Vulcanisation in particular chloroprene rubber (CR) and some other halogenated elastomers (CIIR, CM, CSM, rarely FKM), in which metal oxides such as zinc oxide or magnesium oxide are used as Crosslinking chemicals can be used. This method ensures thermally stable, chemical-resistant and permanently elastic rubber products, which are used particularly in dynamically stressed components.

How does metal oxide crosslinking work?

In contrast to the Sulphur- or Peroxide crosslinking no radical reaction takes place during metal oxide crosslinking. Instead, the functional groups of the Polymers - e.g. the chlorine groups in the CR - with basic metal oxides. This creates ionically or coordinatively bonded networks that give the material particular resistance.

Typically used metal oxides:

Magnesium oxide (MgO) - main cross-linking agent for CR
Zinc oxide (ZnO) - often as a co-crosslinker or activator
Lead oxides (rarely used today due to toxicological concerns)

The reaction usually takes place at temperatures between 150°C and 200°C and is characterised by Anti-ageing agent and additives.

Advantages:

Excellent Resistance to ageing
Very good Flame resistance
Very good adhesion to metals (e.g. for Rubber-metal composite parts)

Disadvantages:

Can only be used for certain elastomers
Longer Cycle times due to slower volcanisation kinetics
Increased electrical conductivity
Possible interactions of the Crosslinking chemicals with other additives

Typical areas of application:

Bearing and damping elements made of CR
Seals in the engine compartment, gearboxes, air conditioning systems
Hoses and moulded parts with oil, weather or flame resistance
Rubber-Metal Composite Parts in construction or rail vehicle technology

Further entries

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Special alloys

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Azo and urea compounds

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FVMQ: Fluorosilicone

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Compression moulding

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Copolymerisation

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Autoclaves

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Toolmaking

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PES: Polyester

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PU: Polyurethane elastomer

PU elastomers are dimensionally stable, abrasion-resistant plastics with high mechanical strength that are ideal for rollers, seals and shock absorbers in heavy-duty industrial applications.

Silane crosslinking

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RoHS

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Rapid tooling

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Rubber caps

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Cycle time

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Crosslinking chemicals

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Sealing lips

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Polyurethane (PU)

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brass

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TPE: Thermoplastic elastomers

TPEs are elastic, malleable materials with rubber-like behaviour that can be thermally processed and recycled like plastics - ideal for flexible seals, handles and hybrid parts.

Inserts

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Transfer moulding

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Elastomer rollers

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Seals

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Engine damper

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Degreasing

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Elongation

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Cold resistance

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Stress cracking

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Titanium

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Fatigue

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Valves

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PPA: Polyphthalamide

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Tool costs

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Rubber

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Vibratory finishing (barrel finishing)

Mass finishing or barrel finishing is a mechanical mass finishing process in which surfaces are machined and burrs removed using abrasive media and movement.

Compound

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Shore hardness

The Shore hardness measures how deeply a test pin penetrates a material and thus provides information about its degree of hardness - a decisive factor in the selection of elastic and technical materials.

Anti-ageing agent

Anti-ageing agents are functional additives that protect elastomers and plastics from damaging influences such as oxygen, ozone, UV radiation or heat, thereby significantly extending their service life.

Rubber blank

A rubber blank is a non-crosslinked, mouldable elastomer precursor that is processed in moulding tools to produce elastic rubber parts.

Molded Rubber Parts

Moulded rubber parts are elastic components made from vulcanised rubber by pressing, transfer moulding or injection moulding. They are manufactured according to drawings and are used as sealing, damping or functional elements in technical applications.

Fillers

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Metal oxide crosslinking

Metal oxide crosslinking is a crosslinking process that is mainly used for chloroprene rubber and produces particularly durable, ageing and flame-resistant rubber parts.

Injection moulding

Injection moulding is a precise moulding process for manufacturing complex plastic and rubber parts in which the material is injected into a mould under pressure and cured there.

Sealed seats

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Vibration dampers

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Grommets

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PA: Polyamide

Polyamide (PA) is a robust, wear-resistant plastic with very good strength and chemical resistance, which is used in particular in technical components and rubber-plastic composite systems.

Biocompatibility

The proof of biocompatibility proves through standardised tests that a medical device or material does not cause any harmful reactions in the human body.

Caoutchouc vs. rubber vs. elastomer

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Bellows

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Mould cavity / cavity

Mould cavities are the cavities in a mould that give the component its final geometry during the moulding process.

Rubber-fabric composite parts

Rubber-fabric composite parts are elastic components with integrated fabric inserts that ensure high tensile strength, dimensional stability and dynamic load-bearing capacity - for example in membranes, seals or conveyor belts.

Polymerisation

Polymerisation is the chemical reaction in which many monomers are combined to form long polymer chains - the basis for plastics and rubber elastomers.

ISO 9001

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LABS (paint wetting impairment substances)

LABS are substances that interfere with the wetting of paints and must therefore be strictly avoided or tested in paint-critical applications.

NBR: Acrylonitrile butadiene rubber

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Medical device regulation (MDR)

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Extrusion of rubber

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Elasticity

Elasticity is the ability of a material to deform under load and then return completely to its original shape - essential for flexible technical components.

Sulphur crosslinking

Sulphur crosslinking is a proven vulcanisation process in which rubber is crosslinked with the aid of sulphur to form an elastic, dimensionally stable and mechanically resilient material.

Tool cleaning

Tool cleaning ensures reliable, clean moulding, protects against burr formation and extends the service life of tools in series production.

Synthetic rubber

Synthetic rubber is an industrially manufactured elastomer material that is categorised into main chemical groups and whose properties can be specifically adapted to technical requirements.

CAD modelling

CAD modelling is the digital design of technical components and tools that serves as the basis for production, simulation and prototype development in industry.

Prototype construction

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ABS: Acrylonitrile butadiene styrene

Acrylonitrile butadiene styrene (ABS) is a robust, impact-resistant and easy-to-process plastic that is used for housings, interior parts and rubber-plastic composite components with high surface and dimensional stability requirements.

Rubber buffers

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RTV silicone: Room temperature curing solid silicone

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HNBR: Hydrogenated NBR

HNBR is a particularly heat-, oil- and ageing-resistant elastomer that is ideal for durable seals and technical components in dynamically stressed applications.

SBR: styrene-butadiene rubber

SBR is a cost-effective, abrasion-resistant elastomer with good mechanical properties that is mainly used in tyres, seals and general moulded rubber parts.

Stainless steel

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Vacuum cups

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HTV silicone: High-temperature curing solid silicone

HTV silicone is a high-temperature curing solid silicone rubber that becomes a permanently elastic material when heated. It combines high mechanical strength with excellent resistance to temperature, ageing and chemicals.

Plasticiser

Plasticisers are additives that make rubber and plastics more elastic and easier to process and are mainly used in flexible sealing and moulded parts.

Deburring

Deburring is the process of removing burrs from components to ensure the function, appearance and safety of technical products.

Express Services

Express production refers to the particularly fast production of prototypes, tools or small batches and accelerated development projects with drastically reduced delivery times.

PP: Polypropylene

Polypropylene (PP) is a lightweight, chemical-resistant thermoplastic with a wide range of applications that is ideal for technical plastic parts and rubber-plastic composite solutions.

Aluminium

Aluminium is a lightweight, corrosion-resistant material with high thermal conductivity that is used in a variety of ways as a construction material and support element in technical components.

Freeze deburring

Freeze deburring is a process for removing burrs, particularly on rubber parts, by cooling and mechanical blasting.

Saturated and unsaturated polymers

Saturated polymers have only single bonds in the main chain and are resistant to ageing, while unsaturated polymers contain double bonds in the main chain and are easier to crosslink; EPDM is a speciality because its double bond is in the side chain.

Housing and cover with integrated seal

Housings and covers with integrated seals are components in which the sealing function is embedded directly in the plastic or metal part. The sealing function is usually realised as an overmoulded or pressed-in rubber sealing lip. They enable reliable sealing without a separate sealing component and are often used for compact, easy-to-install assemblies.

Shaft seal

A shaft seal is a sealing element that seals between a rotating shaft and a housing. It prevents lubricants from escaping and at the same time protects against dirt, dust and moisture.

Adhesion promoter

Adhesion promoters are chemical bonding agents that permanently bond rubber with other materials and thus form the basis for resilient rubber composite parts.

Rubber-Plastic Composite Parts

Rubber-plastic composite parts are hybrid components in which elastic and thermoplastic components are functionally combined - ideal for seals, housings and flexible technical solutions.

Peroxide crosslinking

Peroxides are reactive cross-linking chemicals that produce stable, temperature- and chemical-resistant elastomer structures without sulphur bridges in rubber processing.

Keyboard and switch covers

Keyboard and switch covers are elastic protective components that protect keys and operating elements from dust, moisture and dirt. At the same time, they maintain the operating function by transmitting the actuation feel and enabling reliable sealing.

Rubber recycling

Rubber recycling includes mechanical, thermal and chemical processes for the reuse of vulcanised rubber products as raw materials or additives in new applications.

Primer

Primers are adhesion-promoting primers that improve the adhesion between rubber, plastic or metal and ensure a permanent bond in composite and coating applications.

Ageing

Ageing describes the gradual change in material properties due to external influences such as heat, UV radiation or media, which can lead to long-term impairment of function and service life.

Vulcanisation

Vulcanisation is the process in which raw rubber is converted into a permanently elastic, dimensionally stable and durable rubber state through chemical cross-linking.

Series production

Series production refers to the repeated, economical manufacture of similar components in large quantities.

Rebound resilience

Rebound resilience describes the ability of a material to return energy after rapid deformation - crucial for dynamic applications such as spring elements or dampers.

Heat resistance

Heat-resistant materials retain their properties at high temperatures and are ideal for industrial and technical applications.

Adhesion

Adhesion is the physical holding force between two different materials at their interface and is a key factor for strong, durable connections in technology and industry.

VMQ: Silicone rubber

Silicone rubber (VMQ) is a heat-, cold- and UV-resistant elastomer with very good insulation and media resistance, which is frequently used in medical, food and automotive technology.

Glass transition temperature

The glass transition temperature (Tg) is the temperature range in which a polymer changes from elastic to glassy and largely determines its low-temperature flexibility.

FDA conformity

FDA compliance means that a material or product meets the requirements of the U.S. Food and Drug Administration and is safe for contact with food, drinking water or pharmaceutical applications. Only approved ingredients may be used and the material must not release any substances of concern into the medium.

Profile seal

A profile seal is a seal with a defined cross-sectional shape (round, rectangular, hollow or with a complex profile) that ensures a seal between two components. It is made from elastomers and is used wherever gaps, movements or unevenness need to be compensated for.

Suction pad

Suction cups are cup-shaped suction cups made of elastomer or plastic that cling elastically to the surface and trap the resulting vacuum. Suction cups create an adhesive connection between the gripper and the workpiece by means of negative pressure.

DIN ISO 3302-1

DIN ISO 3302-1 defines the general tolerances for moulded rubber parts and is an international standard for ensuring dimensional accuracy in elastomer processing.

Valve seal

A valve seal is an elastic component that reliably seals the flow of gases or liquids in a valve. The seal prevents leaks, compensates for pressure and temperature changes and ensures that the valve fulfils its switching, control or shut-off function reliably and permanently.

REACH

REACH is an EU regulation for the registration, evaluation and regulation of chemical substances in order to better protect people and the environment. Companies must prove the safety of the raw materials they use and inform customers if their products contain substances of concern.