Stone wool is made from volcanic rock, mostly silicates such as basalt and recycled slag from the steel industry, among others. Its multidirectional fibrous structure enables it to store relatively immobile air inside, making it ideal to fit it in building structures as thermal or acoustic insulation and as passive protection against fire in buildings.

The stone wool production process consists of 5 key stages: rock crushing, rock melting, spinning, pressing and curing of rock fibres and, finally, some processes to shape the final product.

First, rocks are crushed so that they all have a uniform size and weight. They are then placed in a furnace to melt at temperatures close to 1500 °C, similar to those inside a volcano. The obtained lava is passed through rollers that disperse, by centrifugal force, the molten rock in small fibres to cool the product, a process similar to how candyfloss is made. These fibres then cool down and are pressed.

At the time of pressing it is necessary to add essential additives for the production process, such as silicone emulsions that bind the fibres and prevent the stone wool from sticking to rollers at the production line while aiding slip on conveyor belts.

Finally the stone wool is dried in a furnace to eliminate the water that has been added and then it undergoes the processes of compaction and cutting before the quality controls and packaging. Silicone emulsions also have a positive impact on cutting processes, as they give stone wool waterproofing properties, which are important for cutting processes by means of pressurised water, and at the same time improve cutting by metallic cutters.

Silicone emulsions contain a silicone compound (usually silicone oil), water and the emulsifiers necessary to obtain a stable emulsion. From a chemical perspective, a silicone compound is a finite chain of silicon and oxygen atoms bonded together. In addition to these links, silicon forms two other links with organic groups, in most cases methyl (CH3) groups that give silicone compounds their characteristic semi-organic behaviour. For stone wool production silicone emulsions are added to a mixture of cutting fluid and water.

Concentrol manufactures silicone emulsions with specific properties to tackle the challenges met by stone wool producers. The product lines that are prepared for this sector are silicone macro and micro-emulsions with a particle size from 0.1 to 1 microns and less than 0.4 microns, respectively. The micro-emulsions are of higher performance and allow lower dosages. They all belong to the EMULTROL range and have good moistening, so they are easy to apply by means of vaporizers. Silicone macro-emulsions can be formulated with silicone oils of different viscosities, the most common being 350cps and 1000cps, while micro-emulsions are formulated with high viscosity silicone oil (> 100,000).

The denser stone wool is, the better the insulation is but the lesser the efficiency of silicone additives. Concentrol has carried out homologation tests of EMULTROL silicone emulsion lines for high-density stone wool to evaluate their performance and properties, with excellent results.

EMULTROL silicone emulsion properties for stone wool producers:
– Application by means of vaporizers.
– Binding properties to prevent fibres from dispersing.
– Lubricating properties during the production process so that the product does not stick to conveyor belts or rollers.
– Improved cut by metallic cutters.
– Water repellent, avoiding water accumulation.
– Soft to the touch finished product.
– All lines are free from alkylphenols.
– All the lines offered by Concentrol comply with the FDA regulations and some with the Regulation (EU) 10/2011 (Fig. 3).

EMULTROL silicone emulsions, manufactured by Concentrol, offer excellent yields in the production of stone wool, some of the lines maintain their properties even in very low temperature conditions.

Concentrol has long experience in the synthesis of silicone-based products. A complete control of their production and a highly qualified technical team allow us to adapt them to different requirements and situations, adjusting their properties so that they offer excellent results with the best cost-quality ratio. Contact us for more information.