Industrial silicone oil: properties, advantages, and applications

Industrial silicone oil is a synthetic fluid used in numerous technical applications when performance beyond simple lubrication is required.

Depending on the formulation, industrial silicone oils can offer:

• stability to temperature variations,
• dielectric properties,
• water repellency,
• low surface tension,
• damping capacity,
• oxidation resistance.

Due to these characteristics, silicone oil for industrial use finds application in very different fields: from the lubrication of plastic and rubber components to damping systems, transformers, and electrical equipment, through to release agents.

However, not all silicone oils are the same. Composition, viscosity, operating temperature, materials, and the required function of the fluid are determining parameters for identifying the most suitable solution.

What industrial silicone oils are

The industrial silicone oils are synthetic fluids belonging to the family of polysiloxanes, materials characterized by a main structure formed by alternating atoms of of silicon and oxygen, to which organic groups.

This structure distinguishes silicone fluids from many conventional oils and organic fluids and contributes to their technical characteristics.

Silicone oil represents the fluid form of this technology and is used when the behavior of the liquid must perform a precise function within a component, a machine, or an industrial process.

One of the most widespread families is that of polydimethylsiloxanes, or PDMS, available in a wide viscosity range and used in numerous technical applications.

How silicone oils are composed

The structure of silicone oils can be modified by varying the organic groups attached to the silicon-oxygen chain.

This possibility allows for the development of fluids with different characteristics in terms of:

• viscosity,
• thermal resistance,
• low-temperature behavior,
• chemical resistance,
• lubricating properties,
• electrical characteristics.

Speaking generically of silicone oil identifies a family of materials, but does not yet allow for the definition of their performance. To understand the behavior of an industrial silicone oil, it is necessary to consider both the chemical composition and the viscosity.

Properties of silicone oils in industrial applications

Industrial silicone oils are chosen primarily because they can combine multiple technical properties within the same fluid. Performance always depends on the specific formulation, but certain characteristics are particularly relevant in industrial applications.

Stability to temperature variations

In industrial applications subject to thermal variations, one of the advantages of silicone oils is the ability to maintain a relatively stable viscous behavior as temperature varies. This allows for a more predictable response of the fluid even when operating conditions change.

This property becomes particularly important in systems where viscosity influences the behavior of the component directly, such as dampers, shock absorbers, viscous couplings, and controlled mechanisms.

Thermal and thermo-oxidative stability

Many silicone oils exhibit good thermal stability and oxidation resistance. This allows them to be used in processes where the fluid must maintain its characteristics even in the presence of high temperatures or prolonged exposure.

However, there is no single thermal range valid for all silicone oils: the operating temperature must be verified for each individual product.

Viscosity stability

Viscosity tends to decrease when the temperature increases and to increase when the temperature decreases. In silicone oil, this variation can be relatively limited compared to that of other fluids.

In an industrial application, this means being able to maintain a more consistent system response even as thermal conditions change.

Dielectric properties

Specific silicone oils can offer high dielectric properties and be used as insulating fluids. This characteristic allows their use in applications such as transformers and electrical equipment, where the fluid can contribute to both insulation and thermal management.

Electrical performance must nonetheless be evaluated based on the formulation and operating conditions, including the presence of moisture.

Low surface tension and spreadability

Many types of silicone oil exhibit low surface tension, a characteristic that favors their distribution across a surface. This behavior can be exploited in industrial applications for release, surface treatment, and lubrication.

Water repellency

Specific silicone fluids show marked water repellency, useful in systems where it is necessary to limit the interaction between the surface and water. This property can contribute to the protection of the component and the maintenance of performance in the presence of moisture.

Shear stability

Some silicone oils exhibit good stability under shear stress, maintaining their characteristics even when subjected repeatedly to movement and deformation. This is an important advantage in dynamic systems where the silicone oil works continuously.

Damping capacity

The viscous behavior of silicone oil can also be exploited to control movement and dissipate energy. In these cases, the fluid does not simply perform a lubricating function but becomes part of the operation of the component.

Why choose an industrial silicone oil

An industrial silicone oil becomes particularly useful when the application requires multiple properties simultaneously and stable behavior under variable operating conditions.

Key advantages include:

• Viscosity stability with temperature: useful for maintaining a more uniform system response.
• Use across extended thermal ranges: even in the presence of temperature cycles or variations.
• Dielectric properties: relevant in electrical applications.
• Compatibility with plastics, rubbers, and elastomers: always to be verified on the specific material.
• Water repellency and surface behavior: useful in specific industrial treatments and processes.
• Ability to perform functions beyond lubrication, such as damping, insulation, heat transfer, and release.

The versatility of industrial silicone oils stems precisely from the possibility of combining these characteristics within the same fluid, depending on the formulation and application.

The role of viscosity in industrial silicone oils

Viscosity is one of the fundamental parameters in choosing an industrial silicone oil. It indicates the resistance of the fluid to flow and directly influences how the oil:

• distributes itself;
• flows within the component;
• remains in the application area;
• reacts to movement;
• contributes to damping.

Silicone oils can be produced in a very wide range of viscosities.

What changes when increasing viscosity

A low-viscosity silicone oil is generally more fluid and tends to distribute more easily. Conversely, as viscosity increases, the resistance to flow grows.

This behavior is exploited primarily in industrial systems where the fluid must control the speed or consistency of a movement.

There is therefore no ideal viscosity valid for every application. The choice depends on:

• operating temperature;
• movement speed;
• system geometry;
• materials involved;
• required function;
• load conditions;
• operating duration.

It is also important to always consider the temperature at which the viscosity is declared, because the value varies as thermal conditions change.

Applications of silicone oils in different industrial sectors

The combination of thermal stability, controlled viscous behavior, dielectric properties, and compatibility with different materials allows silicone oils to perform different functions depending on the industrial sector.

In some cases, they act directly as lubricants, while in others, they become functional fluids of the system or release agents.

General industry and components

In the production of components and in mechanical systems for general industry, industrial silicone oils can be used to lubricate plastic and rubber parts, facilitate sliding, or control the speed of a movement.

This is the case, for example, for plastic gears, damping mechanisms, seals, and O-rings where the viscosity of the fluid can contribute directly to the component’s response.

In a slowed-down mechanism, therefore, the oil does not simply serve to reduce friction: it opposes a controlled resistance to movement, allowing for a more progressive opening or closing.

Automotive and transport

In the automotive and transport sector, the presence of plastic and rubber components and multi-material couplings makes the use of fluids compatible with these materials particularly interesting.

Silicone oils can find use in:

• damping systems,
• adjustment mechanisms,
• components where it is necessary to maintain a uniform response even as the temperature varies.

In these cases, viscosity becomes part of the design: the fluid can be chosen to determine how quickly a component moves or how intensely a stress is damped.

Energy and electrical equipment

In the energy sector, silicone oil can perform a function completely different from lubrication.

Specific fluids are used within transformers and electrical equipment, where they must simultaneously contribute to electrical insulation and the dissipation of heat generated during operation.

The fluid surrounds the internal components of the transformer, absorbs the heat produced, and helps transfer it toward the dissipation zones, while maintaining the dielectric properties required by the system.

An example is XIAMETER™ PMX-561 Transformer Liquid, a PDMS silicone fluid developed specifically for the cooling and insulation of transformers and electrical equipment.

How to choose an industrial silicone oil

The choice of industrial silicone oil must start from the actual conditions of the application and the function required of the fluid.

The main parameters to evaluate are:

• Fluid function.
• Viscosity: to be chosen based on temperature, movement, and system geometry.
• Operating temperature: considering minimum and maximum values and potential continuous exposure.
• Materials involved: verifying compatibility with plastics, rubbers, elastomers, metals, and insulating materials.
• Load and type of movement: including contact pressure, speed, vibrations, and frequency of use.
• Operating environment: such as the presence of water, moisture, chemicals, dust, or contaminants.
• Dielectric properties: when the fluid is used in electrical equipment.

Evaluating these aspects as a whole allows for the identification of an industrial silicone oil consistent with the operating conditions, avoiding basing the choice on a single parameter like viscosity.

Mascherpa solutions for different industrial applications

The variety of functions performed by silicone oils is represented by solutions intended for different industrial applications.

Frequently asked questions about industrial silicone oil

From silicone oil properties to industrial application

The variety of industrial silicone oils demonstrates why it is not enough to choose a product based solely on the definition of “silicone oil”.

A fluid intended for damping, a dielectric oil for transformers, and a silicone oil for lubrication and release may belong to the same technological family, but meet completely different needs.

To identify the correct solution, it is necessary to evaluate all the properties analyzed throughout the article together.

Mascherpa supports companies in the selection of silicone oils and silicone technology solutions for industrial applications, starting from the operating conditions and technical requirements of the system. For more information, contact the Mascherpa experts.