Expandable Graphite

Discover the versatility

of an innovative raw material

 

In a world where material innovation is driving progress, expandable graphite stands as a remarkable example of the versatility and transformative power of material science. This unique form of graphite, also known as expandable graphite, has attracted the attention of various industries and established itself as an indispensable component of numerous applications.

Expandable graphite differs fundamentally from conventional graphite due to its remarkable ability to expand greatly when heated.

This expansion occurs due to the structure of the graphite, which consists of layers separated by gaps. When these spaces are activated by heat, the material expands rapidly, giving it a porous, lightweight structure. This property predestines the material for use in various fire protection applications.

The production of expandable graphite is a fascinating process that requires careful control and expertise. Based on our many years of experience and a global network, we can offer expandable graphite with properties that are specifically tailored to our customers’ requirements

The areas of application for expandable graphite are as varied as they are impressive. The material is ideal for use in building fire protection.

Expandable graphite is used, for example, in penetration seals for pipes and cables, between firewalls and ventilation systems. Seals with expandable graphite protect doors and windows in the event of fire. In paints and varnishes, expandable graphite provides fire protection for steel beams, for example. Expandable graphite is also used as a fire protection additive in the textile industry. The carpet backings of aircraft carpets or passenger trains contain expandable graphite, as do innovative fire protection jackets. In addition to its use in fire protection applications, the expanding property is also used in other applications, e.g. in metallurgy, where expandable graphite is used in covering powders. By expanding the graphite, the heat/energy is retained for longer.

ADVANTAGES OF RMC

Long-standing partnerships

Thanks to our long-standing partnerships, we benefit from constant further developments, familiar production processes and efficient logistics.

Technical advice

Our many years of experience in the field of technical carbons enable us to provide individual, technical advice based on your application.

Quality control within Germany

The expandable graphites on offer are tested and approved in the German laboratory on a batch-by-batch basis. New developments are also tested and delivery
sources validated on this basis.

rEach compliant, iso 9001:2015, Ecovadis


We ensure REACH compliance for all materials, are ISO 9001:2015 certified and a member of Ecovadis.

Rapid availability

The storage of standard types in the German warehouse enables rapid deliveries. We usually supply our customers on the basis of framework agreements, which are then held in the German warehouse for the long term. This enables flexible, rapid delivery without long delivery times and minimizes logistics risks in worldwide transport.

Further development

We see ourselves as a supply partner who not only supplies existing raw materials, but also develops them further in cooperation with the customer if necessary. We are characterized by the implementation of new ideas and adaptations.

 

FROM NATURE

Graphite – the natural base

fLAm and BraND protection

 

Graphite is one of the most natural forms of carbon in its pure form, characterized by the hexagonal crystal lattice system. Gráphein means writing in ancient Greek, from which the name graphite is derived, as graphite leaves the characteristic grey line color on paper or rough surfaces.

It has been used in Europe for centuries and is characterized by its high temperature resistance. In an oxygen-free environment, graphite only sublimates at a temperature of well over 3,000°C. Graphite is resistant to non-oxidizing acids and is an excellent electrical and thermal conductor with anisotropic properties.

The conductivity here is formed along the layers, but not across the layers. Due to the aforementioned hexagonal layer lattice structure and the weak Van der Waals forces between the individual layers, these can not only be easily moved against each other (lubricating property), but also allow the introduction of expanded salts.

With the help of these acid compounds, which are stored between the layers, the material expands many times its original volume when exposed to heat.

Layered grid structure enables unique properties

Heat resistant up to > 3000° C (in =O2-free atmosphere).

Molecules can be embedded between the graphite layers.

These stored bloating salts/
acid compounds expand when exposed to heat.

Enormous increase in volume – up to 500 times the original
volume possible.

FROM GRAPHITE ORE TO EXFOLIATED GRAPHITE

 

IMPOSSIBLE

IN MANY INDUSTRIES

INDUSTRIES AND APPLICATIONS

 

CHARACTERISTICS

Purity

The purity of exfoliated graphite is classified by its carbon content. This is adjusted by means of flotation / chem. Purification (see production). In principle, our expandable graphites are available in the purity levels 90 % – 99 % carbon. As the expansion properties are largely dependent on the selection of the graphite flake (origin / grain size) and the intercalation agent, the carbon content is usually not the main focus when selecting the type. As standard, our expandable graphites have a purity of 95 % – 98 % carbon.

Moisture content

The moisture content of the expandable graphite is typically >1 %. With special processing specifications, this can be reduced to < 0.5 % to < 0.2 % depending on the type

pH value

Our standard types are generally specified with a neutral pH value (5-9). The pH value depends on the manufacturing process and the processing of the material. An acidic expandable graphite pH <4 can indicate poor cleaning of the graphite or the leaching out of expanded salts based on a damaged expandable graphite flake (high shear forces/partitioning of the flake). This can lead to chemical reactions or even corrosion. Please contact us if you require expandable graphite in an alkaline environment.   For this we have a variety with pH 9 – 11.

Particle sizes, expansion pressure,
Expansion volume

The three parameters: Grain size, expansion volume and expansion pressure are parameters that are interdependent. Due to the layer lattice structure of graphite, the larger the flake size, the better the expansion properties, as the number of layers then enables greater expansion.

The choice of grain size therefore has a significant influence on the material properties.

Our standard types have a grain size of 80 % >250 µm. The blowing rates here are approx. 250 – 300 times the original volume.

With our coarsest grades, such as BLG 400L) 80 % > 500 µm, we achieve blowing rates of > 450 ml/g.

The expandable graphite with the smallest grain size (BLG40T) has a grain size of 80 % < 75 µm. The expansion here is just40 cm³/g.

In addition to determining the volume increase, the types are also tested with regard to the expansion pressure. These parameters are also dependent on the particle size and can be defined together

Starting temperature

The start temperature defines the temperature at which the process of graphite expansion or swelling begins. We measure the first significant movements in the material here. The expandable graphite expands from this temperature point. It should be noted that this does not happen explosively from the starting point, but requires an increase in the temperature curve. Depending on the type, the complete increase in volume is only achieved at a temperature of 600°C – 1,000°C.

The starting temperature is usually between 180°C – 200°C. We also offer types with lower starting temperatures (130°C – 170°C). In addition, high processing temperatures can mean that expandable graphites with a higher starting temperature are required, e.g. for polymers such as polyamide. For this purpose, we offer expandable graphites with late starting temperatures of up to 290°C.

Remacon standard type overview (typical values)

Standard expandable graphite in different grain sizes

Expandable graphite with high expansion

Expandable graphite with high starting temperature

Expandable graphite with fine grain size

RMC Remacon

Based in Bad Säckingen on the Upper Rhine, RMC Remacon today supplies technical carbons all over the world. Our customers include small and medium-sized companies as well as large global corporations. In the end, our expandable graphite is used to produce a wide variety of flame retardant coatings, fillers for pipe sleeves and cable ducts, additives for PU foams and fire protection additives for the plastics industry. Our consultants have extensive know-how about the possible applications of expandable graphite. We will be happy to advise you on the optimum product for you.

To the contact

Consulting & Contact

Do you have questions or need advice?

Please call us or write to us via our contact form.

RMC Remacon GmbH
Hugo-Herrmann-Str. 15
79713 Bad Säckingen
Germany

Phone. +49 7761 939 930
Mail: info@rmc-remacon.com