For the production of silicone heat mats, the heat conductors, i.e. heating wires or strands, are laid to form the intended design of the heating element and are, then, embedded in silicone. This process is known as vulcanization and requires a considerable amount of energy since the silicone must be subjected to high degrees of thermal energy so that it can be mechanically deformed as desired. Silicone heat mats can withstand continuous temperatures of up to 200 °C (up to 180 °C with self-adhesive film), and they can also withstand higher temperatures (up to 230 °C) for short periods.

It is difficult to predict which temperatures a silicone heat mat will reach, as the temperature output depends on many factors. For example, the heat output depends on the type and mass of the goods to be heated, on air currents or the ambient temperature, which leads us to the following, important question:

At what temperature does silicone melt?
There are different levels of heat resistance for silicone. Normal silicone can withstand temperatures from -50 °C to 300 °C without any problems. Heat-resistant silicones, which can withstand temperatures of up to 1,500 °C, are also used in industrial applications. Although silicones are difficult to ignite/melt, once ignited, silicone burns, leaving only a non-conductive ash. Silicone does not melt just because of high temperatures. Hardened silicone leftovers and scraps from previous production steps can be granulated and added to newly mixed silicone as a filler. Silicone as a material is recyclable. Yet, any silicone heater presents a compound whose components are difficult to separate again, which make recycling rather challenging.

The use of aramid nonwoven is not widely known. Therefore, we would like to address the following question:

What is aramid?
Aramid is a lexical compound orclipping of the expression ‘aromatic polyamide,’ which denotes a variety of liquid crystal polymers, and it is mainly processed in the form of fibers. Aramid is divided into three main groups: meta-aramids, para-aramids and para-aramid copolymers. All three groups are characterized by the fact that the aramid has high heat resistance and the fibers are flame-resistant.

Aramid fibers are suitable for very demanding applications, and they are widely used in the firefighting industry (manufacturing of firefighters’ clothing) because of their flame retardant properties. Aramid is not only fireproof, the aramid fibers also have a high tensile strength, which is why they are often used for bulletproof vests (military and police) or for armoring selected emergency vehicles.

A special property of aramid nonwovens is its good thermal insulation. The laid heating wire creates a very high heat output, which is insulated by the nonwoven. Aramid has a high heat resistance, which is an enormous advantage since laying the heating wire generates a very high heat output which is further enhanced by the insulation provided by the aramid nonwoven carrier. In addition, the nonwoven is either not combustible or flame retardant and can be used for a temperature ranges of up to 200°C.

To summarize: Aramid nonwoven heat mats are very similar to silicone heat mats, but they have even more advantages. For example, the aramid fibers have an enormous tensile strength at a very low weight. They offer an enormous performance and a very high level of protection which translates into a very high resistance to impacts, cuts and abrasion. At Embro, we believe in the extremely beneficial properties of aramid and only manufacture heat mats from aramid fibers.