Silicone rubber: The complete guide to types, applications and market developments 2026

What is silicone rubber and why is it so special?

Silicone rubber is a synthetic elastomer material based on silicon, oxygen, carbon, and hydrogen. Unlike classic organic rubbers such as EPDM, NBR, or natural rubber, whose polymer backbone is essentially based on carbon-carbon bonds, silicone rubber is based on a silicon-oxygen chain, the so-called siloxane backbone. This structure forms the basis for a property profile that differs significantly from many other elastomer materials.

Key characteristics include a very wide temperature range, high resistance to UV radiation, ozone, and weathering, excellent electrical insulation properties, and good elasticity over extended periods. Depending on the formulation and quality, silicone rubber can also be suitable for applications involving food contact, skin contact, or in medical technology.

Typical advantages of silicone rubber

• Operating ranges from approximately minus 60 degrees Celsius to plus 250 degrees Celsius, and even higher for special types.
• very good resistance to UV radiation, ozone and aging
• good electrical insulation properties over a wide temperature range
• Low compression deformation with suitable design, which is crucial for continuously stressed seals.
• Availability in very different hardnesses, colors and processing forms

This combination of temperature resistance, aging stability, insulation properties and long-term elasticity makes silicone rubber one of the most important elastomer materials in many demanding applications.

This combination of temperature resistance, aging stability, insulation properties and long-term elasticity makes silicone rubber one of the most important elastomer materials in many demanding applications.

An overview of the most important silicone rubber types

Not all silicone rubber is created equal. This material class encompasses a wide variety of types that differ fundamentally in their processing methods, curing mechanisms, and performance profiles. Anyone wanting to select the right material for their application needs to understand these differences.

Material group	Typical processing	Cross-linking / Hardening	Performance profile	Typical applications	Current developments
HTV / HCR	Extrusion, compression molding, transfer molding, compression molding	High-temperature vulcanization, mostly peroxide or addition crosslinking	High mechanical strength, good elasticity, wide hardness ranges, good temperature resistance	Seals, cable insulation, profiles, hoses, technical molded parts	Ceramicizing compounds, improved flame retardant systems, specialized high-performance grades
LSR	Injection molding using the LIM process	Platinum-catalyzed addition crosslinking	Highly automatable, high reproducibility, suitable for delicate and complex geometries, short cycle times	Precision parts, seals, medical devices, baby products, electronic components	Medical and biocompatible grades, self-adhesive systems, optical and highly transparent types
RTV-1	Applying, dosing, sealing	Moisture crosslinking, one-component	Easy to use, no mixing required, good for assembly and maintenance	Sealants, adhesive and sealing applications, FIPG, repair and maintenance work	Low-emission systems, faster skin formation and curing profiles, improved adhesion to challenging substrates
RTV-2	Casting, pouring, coating, mold making	Two-component, condensation or addition crosslinking	Versatile, also suitable for larger volumes, good detail reproduction, wide property windows	Potting compounds, mold making, prototyping, electronics protection, technical molded parts	Fast-curing systems, softer special types, highly transparent and thermally conductive variants
Fluorosilicones (FVMQ)	Processing similar to HCR or LSR, depending on the type	Networking analogous to silicone rubber systems	High resistance to fuels, oils and non-polar media combined with good temperature resistance	Seals in fuel systems, O-rings, membranes, aerospace and automotive applications	Highly specialized qualities for aggressive media and demanding mobility applications
Silicone sponge / silicone foam	Extrusion, compression molding, foaming processes	Networking with targeted cell structure, open-cell or closed-cell	Low weight, good compressibility, thermal insulation, damping	Seals, padding, vibration damping, thermal and electrical insulation	Applications in the battery environment, fire protection solutions, lighter and more powerful cell structures
Conductive silicone rubber	Compounding with conductive fillers, followed by extrusion, compression molding or injection molding	Cross-linking as with standard silicones	Electrical conductivity, ESD protection, EMI and EMC shielding, elastic function despite conductivity	Shielding seals, contact elements, sensors, electronic applications	Soft sensors, wearables, function-integrated elastomer components
Thermally conductive silicones (TIM)	Processing as pads, gap fillers, gels, pastes, adhesives or potting compounds	Depending on the system, it is one- or two-component, usually addition-curing or physically configured	High thermal conductivity, compensation of tolerances, protection of sensitive components	Battery packs, power electronics, LEDs, control units, thermal management	Higher thermal conductivity gap fillers, automatable dispensing systems, materials for e-mobility and high-performance electronics

High-temperature vulcanizing silicone rubber (HTV / HCR)

HTV silicone, also known in technical terms as High Consistency Rubber (HCR), is a solid, high-viscosity silicone rubber that is vulcanized under heat and pressure. It belongs to the classic material groups of the silicone industry and has been used for decades for molded parts, extruded profiles, hoses, and sheets.

Processing is typically carried out by compression molding, transfer molding, or extrusion. HTV offers high mechanical strength and can be formulated to achieve a wide range of hardnesses, typically in the range of approximately 20 to 80 Shore A.

Typical applications include seals and O-rings for higher temperatures, cable insulation, exhaust hangers in the automotive industry, high-voltage insulators, fire protection sheathing, and profiles for construction and industry.

A recent development is the use of ceramic HTV compounds. These special formulations form a ceramic-like protective layer when exposed to fire, maintaining electrical insulation for as long as possible, even under high thermal stress. Such systems are becoming increasingly important, particularly in the context of high-voltage batteries, for example, for encasing or protecting busbars and coolant lines.

Liquid silicone rubber (LSR)

Liquid silicone rubber, or LSR for short, is a two-component, low-viscosity silicone system processed using injection molding, most commonly liquid injection molding (LIM). Curing typically occurs via addition curing and platinum catalysis. This process does not produce volatile byproducts, which is a significant advantage for sensitive applications.

LSR has developed into one of the most dynamic segments in the silicone market. Reasons for this include its high degree of automation, very good reproducibility over large production runs, and the ability to economically manufacture intricate geometries with tight tolerances.

Typical applications include seals for electronics and sensors, connectors in the automotive industry, disposable medical products such as catheter components or valves, baby and consumer goods, touch mats and membranes.

The medical sector is particularly relevant for LSR because it has high requirements for purity, biocompatibility, process stability, and traceability. Standards such as ISO 10993 or USP Class VI may be relevant depending on the application. For medical devices, regulatory evaluation as part of the respective product approval process is an additional consideration. The platinum-catalyzed addition system is particularly suitable for such applications because it crosslinks very cleanly and does not release any volatile byproducts.

Room temperature curing silicone rubber (RTV)

RTV silicones form a particularly broad and versatile product family. They cure at room temperature and, compared to HTV or LSR, often do not require complex processing infrastructure. This makes them very attractive for sealing, bonding, potting, and coating applications.

RTV-1

RTV-1 is a single-component, cross-linking system that cures through a reaction with atmospheric moisture from the outside in. These systems are ready to use and are particularly suitable for joints, surface sealing, repairs, and assembly applications. Curing is a relatively slow process, often progressing a few millimeters per 24 hours, depending on the system, temperature, and humidity.

RTV-2

RTV-2 is a two-component system. Both components are mixed before application. This allows for greater layer thicknesses, more defined curing profiles, and wider formulation windows. RTV-2 forms the basis for many mold-making silicones, potting compounds for electronics, and numerous specialized technical applications.

Typical applications include joint and construction sealants, adhesive and sealing applications in equipment and apparatus manufacturing, electronics potting, mold making for prototyping and model making, and sealing solutions in battery environments. RTV systems are also used in structural glazing, but only in formulations specifically qualified and approved for this purpose.

Fluorosilicones (FVMQ)

Fluorosilicones overcome a major weakness of standard silicone rubbers, namely their limited resistance to many nonpolar media. While classic VMQ silicones can swell considerably upon contact with fuels, oils, solvents, or hydraulic fluids, fluorosilicones offer significantly better resistance without completely losing the typical advantages of silicones at low and high temperatures.

The improved media resistance is achieved through fluorine-containing side chains, especially trifluoropropyl groups. However, fluorosilicones are generally more expensive and often somewhat weaker mechanically than standard VMQ systems.

Typical applications include seals in aerospace fuel systems, O-rings for hydraulic systems, membranes for chemically stressed applications, and sealing systems for contact with aviation fuels or more aggressive media.

Silicone sponge and silicone foam

Foamed silicones combine the thermal and chemical resistance of silicone rubber with the advantages of a cellular structure. These include low weight, good compressibility, good resilience, and effective thermal insulation. Depending on the manufacturing process, open-cell or closed-cell structures are produced, which differ significantly in their behavior towards water, air, and pressure.

Typical applications include seals in building glazing and facades, shock absorption in packaging or electronic housings, sound insulation, and thermal insulation in technical systems.

The use of closed-cell silicone foams is growing particularly rapidly in the battery sector. There, they have established themselves as an attractive solution for sealing, thermal insulation, and vibration damping. They offer a favorable combination of sealing, temperature resistance, and low weight.

Conductive silicone rubber

By adding conductive fillers such as metal-coated particles, silver, graphite, or other special additives, silicones can be made electrically conductive or shielding-effective without completely losing their basic elastomeric properties. This makes them suitable for applications where, in addition to sealing, electrical conductivity or electromagnetic shielding is required.

Typical applications include EMI and EMC shielding gaskets in communication and electronic systems, ESD protection components, conductive gaskets for electronic assemblies, and functional materials in sensors and wearables.

Thermally conductive silicones (TIM)

Thermally conductive silicones, often referred to as thermal interface materials or TIMs, are among the most important functional materials in modern thermal management. They fill air gaps between heat-generating components and cooling surfaces, replacing the poorly thermally conductive air with a adaptable material offering significantly higher thermal conductivity.

Depending on the formulation, such systems are available as pads, gels, pastes, gap fillers, adhesives, or potting compounds. This allows them to be adapted to very different component geometries and manufacturing processes.

Typical applications include thermal management in battery packs, heat dissipation in LED systems, power electronics in inverters and industrial plants, and cooling concepts in data centers and telecommunications systems.

Silicone rubber in electromobility

The electrification of transport is one of the most important growth drivers for silicone rubber. Particularly in battery systems, high thermal, electrical, and mechanical demands converge. Silicones perform several functions simultaneously there, especially in thermal management, sealing, and electrical insulation and shielding.

Thermal management

Lithium-ion batteries operate optimally only within a limited temperature range. Both excessively low and excessively high temperatures negatively impact performance, aging, and safety. Therefore, reliable thermal management is crucial.

Thermally conductive silicones such as gap fillers, gels, or pads help to dissipate heat from cells and electronic components to cooling structures. Their adaptability allows them to compensate for tolerances and maintain stable thermal contact even under temperature fluctuations or vibrations.

Additionally, thermally insulating and flame-retardant silicone materials are used where components need to be shielded from each other or protected from high thermal stress. Special ceramizing formulations can form a protective inorganic barrier under extreme heat, thereby improving functionality and fire protection

Sealing and protection against environmental influences

Battery packs must be reliably protected against moisture, dust, dirt, and mechanical stress for many years. At the same time, temperature fluctuations, vibrations, and exposure to various media affect the sealing systems.

Automated silicone sealing systems, such as form-in-place and cure-in-place gaskets, have become established in many applications. Silicone foam also plays an important role when high compressibility, elastic recovery, and thermal insulation are required.

Electrical insulation and shielding

With increasing voltages in modern vehicle architectures, the demands on insulation materials are growing. Silicone rubber offers a favorable combination of electrical insulation, thermal stability, and flexibility. Additionally, conductive silicones are used where electromagnetic interference needs to be shielded or defined discharge paths need to be created.

Why silicones are indispensable in electromobility

Silicones are particularly interesting for many battery applications because they can fulfill several requirements simultaneously: temperature resistance, elasticity, sealing function, electrical insulation, and aging stability. This multifunctionality is precisely the decisive advantage compared to many alternative material classes.

Characteristic	silicone rubber	epoxy resin	Polyurethan
Typical temperature range	very wide	medium	medium
flexibility	very good	low to moderate	good
Long-term elasticity	very good	small amount	medium to good
Electrical insulation	very good	good to very good	good
Automatable application	very good	good	good
UV and aging resistance	very good	usually good	limited depending on the system

Silicone rubber in other key industries

Medical technology

Silicone rubber is the preferred elastomer in medical technology—and this trend is growing. Over 72% of cardiovascular, neurological, and orthopedic devices now incorporate silicone components. The reasons: proven biocompatibility, sterilizability (autoclave, gamma radiation, EtO), hypoallergenic properties, and a long track record of clinical success.

The most important application areas include implants and long-term contact products, catheters and tubing systems, breathing masks and valves, surgical instruments, and wearable health sensors. Current development trends are moving towards antimicrobial silicone formulations and nanostructured surfaces for implants.

High-voltage and energy technology

In high-voltage engineering, silicones are used for composite insulators, cable joints and terminations, feedthrough insulation, and transformer seals. Key performance characteristics include surface hydrophobicity, which reduces tracking current formation, tracking resistance according to IEC 60587, and UV stability over decades in outdoor operation.

With the expansion of renewable energies and the decentralization of electricity grids, the demand for silicon components for photovoltaic inverters, wind turbines and energy storage systems is continuously increasing.

Construction industry and building envelope

Silicone sealants and structural silicone adhesives have been standard components of modern facade and building technology for decades. Structural glazing, the structural bonding of glass panes to metal frames, enables the flush glass facades that characterize the cityscape of modern metropolises.

Other important applications include weatherproofing for expansion joints, fire-resistant joint seals, insulating glass seals, and coatings for concrete and natural stone surfaces. The European Energy Performance of Buildings Directive and the focus on energy-efficient construction are driving demand for high-quality sealing solutions.

General mechanical engineering and industrial applications

Standard seals, O-rings, molded parts, diaphragms, hoses, expansion joints, and damping elements made of silicone rubber form the backbone of industrial maintenance and product development. The material's versatility—adjustable from 20 to 80 Shore A, formulatable in virtually any color, and resistant to a wide range of media—makes it the first choice when organic rubbers reach their thermal or chemical limits.

Market developments and megatrends 2026

A market undergoing structural growth

The global silicone rubber market is growing at an average annual rate of 5 to 6% and is increasingly shaped by three megatrends:

• Electrification of transport: The shift to electric and hybrid vehicles is fundamentally changing the material requirements in the automotive industry. Silicone will not only continue to be needed in existing applications such as seals, hoses, and cable insulation, but is also opening up new, high-volume application areas with sealing solutions for battery packs, thermal interface materials, and fire protection solutions.
• Digitalization and 5G: The increasing power density of electronic systems, from data centers and 5G base stations to autonomous vehicles, generates ever more waste heat that must be dissipated. Thermally conductive silicones and EMI shielding materials directly benefit from this trend.
• Expansion of renewable energies: Solar panels, wind turbines, battery storage systems, and the associated power electronics require materials that function reliably for many years under extreme environmental conditions. Silicone rubber, with its UV stability, weather resistance, and thermal resilience, is ideally suited for this purpose.

European market: Special features of the DACH region

The European silicone rubber market is growing at a CAGR of approximately 5.5% and is expected to reach a volume of over USD 3.2 billion by 2035. For customers in Switzerland, Germany, and Austria, some regional characteristics are particularly relevant.

Price levels in Europe are structurally above the global average, due to higher energy costs, stricter quality and regulatory requirements, and strong demand from the premium automotive and medical technology segments. Conversely, European buyers benefit from geographical proximity to top-tier manufacturers, shorter supply chains, and a secure regulatory procurement environment.

The global market is highly consolidated. The five largest manufacturers—Wacker Chemie, Shin-Etsu Chemical, Dow, Elkem Silicones, and Momentive Performance Materials—together control approximately 70 to 75% of the world market. For European customers, the role of specialized distributors is particularly important. They consolidate various manufacturer brands, offer local warehousing with short delivery times, provide support with technical material selection, and ensure regulatory documentation.

Supply chain resilience: Lessons from recent years

Experiences since 2020 have demonstrated the vulnerability of global supply chains for specialty chemicals. For silicone rubber, particular risk factors include dependence on Chinese silicon metal production, volatility in European energy costs, and sensitivity to logistical disruptions.

For users in the DACH region, collaborating with a specialized distributor is an effective way to minimize risk. A distributor like SILITECH consolidates various European manufacturer brands in its own portfolio and can therefore offer alternative sources of supply for many applications, without the customer having to develop and maintain a complex multi-sourcing strategy with international suppliers. Supplemented by local warehousing in Switzerland, technical advice on material selection, and the handling of regulatory documentation, this creates a procurement model that combines security of supply, short delivery routes, and regulatory compliance.

   Partner - SILITECH AG | Brands & Manufacturers of Specialty Chemicals

Regulatory environment in Europe: What users need to know

REACH and the restriction of cyclic siloxanes (D4, D5, D6)

For industrial users of silicone rubber, the most important news is this: Finished silicone rubber products are generally not affected by the REACH restriction on cyclic siloxanes. Their industrial use as monomers in polymer production remains explicitly exempt, and in high-quality products from European manufacturers, the residual levels of D4, D5, and D6 are typically well below the relevant threshold of 0.1%.

The regulatory background: EU Regulation 2024/1328 restricts the placing on the market of D4, D5, and D6 as pure substances or in mixtures with a concentration of 0.1% or higher, in stages, initially for consumer and professional applications, later for cosmetics, and finally for medical devices. The restriction primarily targets consumer-oriented product categories such as cleaning agents, personal care products, and cosmetics.

Nevertheless, it is particularly advisable for customers whose products are used in end applications with direct consumer or patient contact to request current certificates of analysis from suppliers, including documented D4, D5, and D6 residual values. SILITECH provides this documentation for all distributed silicone grades upon request and offers support with regulatory assessments.

Medical Device Regulation (MDR 2017/745)

The EU Medical Device Regulation has significantly tightened the requirements for materials used in medical applications. For silicone rubber in medical devices, this means more extensive clinical evaluations, stricter documentation requirements, and complete traceability of the entire supply chain, from the silicone manufacturer to the compounder and finally to the processor.

For users who employ silicone rubber in medical end products, material selection also becomes a matter of documentation. Crucially, the entire procurement process must be thoroughly documented, and the supplier must be able to reliably provide the required evidence, from batch traceability and biocompatibility data to declarations of conformity. SILITECH collaborates with manufacturers who offer medical-grade silicone rubbers according to ISO 10993 and USP Class VI and assists in compiling the necessary documentation.

Food contact materials

Silicones intended for direct food contact must comply with EU Regulation 1935/2004 and, where applicable, other national requirements. In Switzerland, food law regulations apply, overseen by the Federal Food Safety and Veterinary Office (FSVO). Addition-curing, platinum-catalyzed silicone grades are often the preferred choice here, as they do not release volatile breakdown products and can be processed very cleanly.

Here too, regulatory compliance hinges on documentation. SILITECH assists in obtaining the necessary declarations of conformity and test certificates, and works with the customer to determine which documentation is required for each specific application.

Sustainability and circular economy

In the context of the EU Green Deal and the Corporate Sustainability Reporting Directive, sustainability characteristics are becoming increasingly relevant for the procurement of technical materials.

Silicone rubber offers significant advantages: an extremely long lifespan, the absence of plasticizers and halogenated flame retardants, chemical inertness, and low toxicity in the event of a fire. The challenges lie in its energy-intensive production and the limited possibilities for material recycling. The industry is working on closed-loop systems and the partial substitution of petrochemical feedstocks with bio-based alternatives.

For users who need to include sustainability indicators in their procurement decisions, SILITECH AG compiles available manufacturer data on environmental indicators and product sustainability upon request.

Material selection: How do I find the right silicone rubber?

Selecting the right type of silicone rubber is both a technical and an economic decision. The following questions will help in systematically narrowing down the options.

1. What temperatures must the material withstand permanently?

For applications up to 200 °C, standard VMQ is generally sufficient. Above 200 °C, specially formulated high-temperature HTV compounds are recommended. For cryogenic applications below −60 °C, special formulations with extended low-temperature performance are available.

2. Which media does the material come into contact with?

Standard silicone rubber is resistant to water, many aqueous solutions, UV radiation, and ozone, but not to fuels, oils, and many solvents. Where contact with nonpolar media is unavoidable, fluorosilicones are the only option.

3. What regulatory requirements apply?

The choice of certification level – industrial, food-grade, medical, or aerospace – determines not only material costs but also delivery times, the supplier base, and the documentation effort. Precise specifications prevent the use of overqualified and therefore unnecessarily expensive materials.

4. Which processing method is used?

HTV/HCR for compression molding and extrusion. LSR for injection molding. RTV-1 for manual application. RTV-2 for potting, mold making, and automated sealing systems. The choice of processing method determines the appropriate silicone type, not the other way around.

5. What volume is needed?

For high-volume production, LSR injection molding is virtually unbeatable in terms of cost-effectiveness. For small batches and prototypes, RTV-2 casting processes or 3D printing with silicone are the more flexible options.

Technological outlook

Additive manufacturing with silicone rubber

3D printing with silicone has made significant progress in recent years, maturing from a laboratory curiosity to a production-ready technology. Various processes, from the extrusion of highly viscous pastes to inkjet-based systems and stereolithography with UV-curing silicone resins, now enable the production of functional prototypes and small-batch parts with material properties approaching those of conventionally processed silicones.

Self-healing silicone elastomers

In basic research, silicone elastomers are being developed that can partially regenerate after mechanical damage. The underlying mechanisms—reversible covalent bonds, hydrogen bond networks, or embedded therapeutic capsules—are promising but are still in an early stage of development.

Bio-based silicones

Several manufacturers are pursuing approaches to substituting petrochemical feedstocks, especially methanol, with bio-based alternatives. The challenge lies in ensuring the same product quality and process stability at competitive costs.

Conclusion

Silicone rubber is one of the most versatile high-performance elastomers in industry. Its strengths lie particularly where temperature resistance, aging stability, electrical insulation, sealing properties, and long-term reliability are required simultaneously. This is precisely why it plays a central role in future markets such as electromobility, medical technology, energy technology, and modern industry.

For users, the key lies not only in choosing silicone, but in selecting the right type of silicone for temperature profile, media contact, processing method, approval requirements and service life specifications.