RTV Silicone

RTV silicone is a versatile silicone material that cures at room temperature and is used in many industrial sectors. It stands out above all for its easy processing, high durability, and flexible application possibilities.

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RTV Silicone - Overview

What is RTV silicone and what types are there?

RTV silicone is a silicone  that cures at room temperature, available as RTV-1, which cures as a single component through atmospheric humidity, and as RTV-2, which cures through mixing as a two-component system.

What is the difference between RTV, HTV, and LSR silicone?

While RTV silicone cures at room temperature, HTV vulcanizes at high temperatures and LSR is used primarily in automated injection moulding and series production processes.

What properties does RTV silicone have?

The most important properties of RTV silicone include flexibility, good processability, temperature and chemical resistance, biocompatibility, and electrical insulation.

What are the advantages of RTV silicone?

Particularly advantageous in RTV silicone are the high dimensional accuracy, the cost-effective and fast prototyping, as well as the elasticity, tear strength, and good colour design capability.

In which sectors is RTV silicone used?

RTV silicone finds application in various industries, including mould making, for seals and bonding, as well as in the prototyping, electronics, and medical industry.

  • Last Update: 
  • 11.08.2026

RTV silicone: definition and types

RTV silicone is a liquid silicone rubber that cures (vulcanizes) at room temperature and is heat-resistant up to around 180 °C. The so-called room-temperature vulcanization means that the material sets without any additional heat supply. After curing, it remains permanently elastic and can, depending on the application, be cast, brushed, spread, or sprayed.

Types of RTV silicone

  • RTV-1: single-component,ready-to-use silicone that vulcanizes through contact with atmospheric moisture
  • RTV-2: two-component system in which curing only begins after mixing the base and the hardener.

Difference between RTV, HTV, and LSR silicone

RTV silicone differs from HTV and LSR silicone above all in curing, processing, and industrial application areas.

Property
RTV silicone
HTV silicone

LSR silicone

Processing method

Casting, brushing, spreading, spraying

Compression and moulding processes

Automated injection moulding

Production type

Small to medium series

Industrial series production

Highly automated mass production

Typical applications

Mould making, bonding, sealing, prototypes

Technical moulded parts, industrial components

High-precision components (electronics, medicine)

Material properties

Very elastic and flexible

Mechanically stable and heat-resistant

Very precise and uniform

Special features

Easy processing, good adhesion on many materials

High temperature and strength resistance

Ideal for automated large-series production

Property

Processing method

RTV silicone

Casting, brushing, spreading, spraying

HTV silicone

Compression and moulding processes

LSR silicone

Automated injection moulding

Property

Production type

RTV silicone

Small to medium series

HTV silicone

Industrial series production

LSR silicone

Highly automated mass production

Property

Typical applications

RTV silicone

Mould making, bonding, sealing, prototypes

HTV silicone

Technical moulded parts, industrial components

LSR silicone

High-precision components (electronics, medicine)

Property

Material properties

RTV silicone

Very elastic and flexible

HTV silicone

Mechanically stable and heat-resistant

LSR silicone

Very precise and uniform

Property

Special features

RTV silicone

Easy processing, good adhesion on many materials

HTV silicone

High temperature and strength resistance

LSR silicone

Ideal for automated large-series production

Properties of RTV silicone

RTV silicone is characterized by its easy processing, pronounced temperature resistance, strong durability, stable structure, and high longevity. In addition, the material is flexible, biocompatible, and has good electrical insulation properties.

  • Easy processing: cures at around 22 °C without any additional heat supply and, thanks to its good flowability, is suitable for mould making and potting applications.
  • High flexibility and low shrinkage: remains elastic after curing and shows a dimensional change of less than 0.1 %.
  • Pronounced temperature resistance: stable from around -50 °C to +180 °C.
  • Strong durability: resistant to chemicals, water, and UV radiation.
  • Good adhesion and material protection: adheres to glass, metal, ceramic, plastic, and rubber without damaging surfaces.
  • Uniform curing (RTV-2): RTV-2 systems cure homogeneously throughout the entire mass, ensuring high dimensional accuracy.
  • Electrical insulation: very good electrical insulation properties for technical applications.
  • Biocompatibility: Suitable for applications with direct or indirect contact with humans.
  • Cost-effectiveness: low acquisition and tooling costs.
1.

Mixing the Components:
Liquid silicone consists of two components that are mixed together in a precise, fixed ratio before processing.

2.

Injection into the Mold (Injection Molding):
The mixed material is injected under low pressure into a specially prepared mold.

3.

Shaping and Vulcanization:
The silicone cures inside the mold. This chemical process is referred to as vulcanization and gives the component its final shape and stability.

4.

Demolding the Component:
After curing, the finished silicone part is removed from the mold.

5.

Thermal Post-Treatment (Tempering, optional):
If required, the parts are post-treated. This removes volatile residues and improves the material properties.

6.

Further Customization and Processing: Depending on the area of application, the component can subsequently be further processed or specifically adapted.

Advantages of RTV silicone at a glance

Dimensional accuracy through low shrinkage

RTV silicone has only a very low shrinkage of about 0.1 %. As a result, the dimensions of the manufactured parts are retained very accurately, enabling high precision. Especially for elongated components, the material ensures stable, uniform, and dimensionally accurate results, as uneven shrinkage is avoided.

Suitable for small to medium series

The material is particularly suitable for producing small and medium quantities. Processing is done manually by mixing the two components, optionally adding colour, and then casting them into a mould. At room temperature, the silicone cures in about 5 to 10 hours.

Low-cost tooling and fast prototyping

Compared to classic metal moulds, the tooling costs are significantly lower. Since no heating or high pressure is required, even simple moulds made of wood or 3D-printed plastic can be used. This saves costs and shortens the production time often to under 24 hours. Overall, it is a simple, largely manual process.

High elasticity and tear strength

Thanks to its pronounced flexibility and stretchability, the material has high tear and tensile strength in its elastic state. In addition, RTV silicone is mostly transparent and can be designed with pigments in various colours.

Application areas of RTV silicone

RTV silicone is a versatile material that, due to its flexibility, durability, and easy processing, is used in a wide range of industries. It is suitable both for product development and for series production.

Typical application areas are:

  • Mould making and surface coating: suitable for producing positive and negative moulds in model and mould making, as well as for coating applications.
  • Sealing and bonding applications: sealing components, machines, and technical systems, as well as joining different materials.
  • Textile finishing: coating textiles to improve protective and functional properties.
  • Small-series production: cost-effective manufacturing of small to medium quantities.
  • Bridge tooling: transitional solutions between prototype development and series production.
  • Test and pre-series production: producing components for functional and stress tests.
  • Functional prototypes: developing and testing products under realistic operating conditions.
  • Glass industry: applications on sensitive glass surfaces and components.
  • Food industry: use in areas with high requirements for hygiene and material compatibility.
  • Electronics industry: insulation, protection, and sealing of electronic components. RTV silicone is often used in electrical engineering as a potting compound to protect sensitive components.
  • Medical and healthcare sector: applications where biocompatibility and material resistance are required.

Frequently Asked Questions

RTV silicone (Room Temperature Vulcanizing Silicone) is a liquid silicone rubber that cures at room temperature. It is flexible, temperature-resistant, and durable. Due to its versatile properties, it is used among other things in mould making, for seals, and in prototype production. RTV silicone is ideal for small to medium series production.

RTV sealant is a silicone that cures at room temperature, used for sealing joints, components, and connections. It is resistant to dust, moisture, many chemicals, as well as high and low temperatures. This makes it suitable for applications in industry, vehicle construction, and electronics. After curing, it remains permanently elastic and ensures a reliable and long-lasting seal.

RTV-1 silicone is a ready-to-use silicone rubber that cures at room temperature. Cross-linking takes place through contact with atmospheric humidity, so no mixing is required. It consists of a polysiloxane and a cross-linker (hardener). After curing, the material remains flexible, elastic, and durable. RTV-1 silicone is often used for bonding, sealing, and insulating and is especially suitable for quick repairs.

RTV-2 silicone consists of two components – a base and a hardener. Curing only begins after mixing both components. RTV-2 cures uniformly throughout the entire mass. It is often used in mould making, for prototypes and small series, and stands out due to its high dimensional accuracy and low shrinkage.

RTV adhesive is a silicone-based adhesive that cures at room temperature while simultaneously bonding and sealing. After curing, it remains elastic and can compensate for movements or vibrations. It adheres to many materials such as metal, glass, and plastic and is frequently used in industry and electronics.

After complete curing, RTV silicone is usually permanently waterproof, provided it has been processed properly and applied correctly. Under these conditions, it forms a flexible, tight barrier against water and moisture. With improper processing or incomplete curing, however, the sealing effect can be impaired.
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