Wood-based insulation material is made of recycled fibre and lingonberry

Cellulose wool made of newsprint is blown in as heat insulation into structures in family homes, residential tower blocks and industrial buildings. Photo: Termex-Eriste Oy
Metsäbiotalouden tulevaisuuskuvasto / Forest Bioeconomy Future Catalogue

The Termex company, located in Saarijärvi, Central Finland, fiberizes recycled paper into wood-based insulation material for buildings. ’Our feedstock is domestic, pre-sorted newsprint,’ says Pasi Typpö, the company’s Development and Marketing Director.

Insulation must protect structures against cold, heat, fire and microbes. It may not cause corrosion in roof trusses assembled with nails, for example, and it may not ignite easily.

In order not to weaken the heat insulation, the material must also prevent air flow sufficiently. To achieve these properties, chemicals are added to the insulation material.

Termex uses a new compound to improve the resistance to fire and microbes of their cellulose insulation materials. The compound is a mixture of aluminium hydroxide and sodium benzoate.

Aluminium hydroxide is used as a fire retardant. Sodium benzoate occurs naturally in plants, such as lingonberry. It protects the leaves and berries of lingonberry against pests and microbes. It is also a common additive to home-cooked jams.

’Sodium benzoate is a natural product used for decades to prevent mould in foodstuffs, and it has now found its way to heat insulation materials as well,’ Typpö says. The compound was developed in collaboration with the Finnish company Chemes Ky.

Another ingredient added to the cellulose wool is water of crystallization. In the event of a fire, this will convert back to water. ’It slows the fire down or may even extinguish it,’ Typpö says. And even if the material should burn, it will not release any toxic compounds.

Pure natural clay is also used as fire retardant in cellulose insulation materials. Extremely fine-ground clay is added to the paper fibres in an air-turbine fiberizer which makes the material porous and a very good insulator.

The clay remains in the product throughout its life span, and the entire product is easy to recycle.

The insulation wool can be used in all floors and walls of buildings. It can be blown in as loose fibres or together with a binding agent, in which case the cellulose fibres will form a batt-like layer.

’Thanks to its good heat insulation performance, the product brings in savings which are many times greater over its life span than the emissions from manufacturing and installation,’ Typpö adds.

According to Typpö, the product’s carbon footprint is one of the lowest among similar products on the market. Wind power is used in the manufacturing process.

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