Innovative moth-protection system for sheepwool insulation
Motivation, content and methods
Renewable insulating materials offer many advantages in the field of sustainable economy, above all they contribute to the improvement of occupants' well being in a qualified and measurable way. Thus they are characterised by being CO2-neutral and requiring considerably less energy for the transformation from raw material to insulating material.
Furthermore, they add to a healthy living climate due to their ability to absorb humidity. Sheep's wool as an insulation material is unsurpassed regarding its humidity buffering effect. Further advantages of these animal insulating materials are the poor inflammability (even without the use of flame retardants fire class B2) and the elimination of pollutants from the air by means of absorbing and binding harmful substances to the keratin fibre. Due to these special product attributes many building owners are willing to pay prices higher than those of other insulating materials.
The only disadvantage of sheep's wool is the danger of moth infestation (clothes moth - Tineola biselliella), which makes it indispensable to equip the raw material with moth repellents. The substance most commonly used for this purpose is Sulcoforon (as contained in MITIN products of the CIBA company), which, being an organic halogen compound, is an avoidable danger to both health and environment and is inconsistent with the requirements of “eco-designed” products when it comes to environmental construction and house building. Mitin is a noxious substance (and its toxicity has not been clarified to this day) that accumulates in biological matrices (for it is very unlikely to be biodegradable) and in case of fire leads to the formation of dioxins, who are well-known for their enormous toxicity.
The disadvantages of conventional moth repellents in sheep's wool and the pending ban on Mitin FF all over the European Union (commencing in July 2006) make it necessary to quickly develop a harmless but effective moth prophylaxis. The substances researched so far, such as Neem tree extracts, cannot guarantee a satisfactory defence against the keratindigesting moth larva due to their lack in temperature stability. In the course of the research project “Moth & Sheep's Wool”, international literature was searched for phytochemical alternatives that have insect repelling effects, the results were evaluated, tested, examined and optimised. The programme contained screening examination, formulation development and state of the art experiments where the clothes moth was exposed in different ways (ovicide, antifeedants , keratin degradation repressing, hormone interfering) to extracts from (mainly local) plants.
Data gained from relevant literature could only be employed in parts for the selection of plants for analysis that consequently were examined for extractions and tests for moth repelling effects, other plants were screened with regard to specific ingredients. Extracts that were effective when tested on moths were subsequently exposed to heat and tested again.
The results of these experiments led to the formulation of a plant extract mixture that for potentialisation was supplemented with mineral components. In addition the antimicrobial efficiency of the plants used was put to the test. A formed component was fabricated for the long running test and integrated into a clay passive house as an insulating panel, where it continues to be monitored.
Results and Conclusions
In the course of the “Moth and Sheep's Wool”-project a composition that was effective when tested on moths and stable despite exposure to heat could be found. It consists of five herbal and two mineral components that complement one another synergistically, as for example in the combination of physical antifeedants, the blocking of keratinases necessary for digesting the wool and a strong repelling effect. In addition to neem and silica - two well-known antifeedants - the roots of a composite plant, an adoxacea and a cruciferous plant, the seeds of a lamiacea and the essential oil of a tropical grass root were chosen. The raw materials needed are available in great quantities for later business application, most of them are also suitable for local cultivation. In addition to the insect repelling effect the chosen plants are effectively antimicrobial and thus also protect sheep's wool against bacterial infestation and mould growth.
Several options for industrial application have been developed and will be tested for applicability and operation costs. Thus - beside the classical spray and dipping method - inserting of hackled plant material, felting of nanofibre (made of keratin or bioplastic such as polylactic acid) filled with moth repellent and application of a molten combination of bioplastic and moth extract through milling are to be considered. Important factors are the amount of raw material needed, costs and energy demand of the relevant procedure, the fixation of the agent on the wool and a certain retardation effect (for long term effect in insulation materials).
During the application technology test a formed component was equipped with the new moth repellent and integrated into a show house to verify the successful prevention of moth infestation. Due to the season - moth infestation is very unlikely in winter - the results cannot be analysed until summer.
The problems that were encountered when producing the formed component with the simplest available application technique - inserting hackled plant material and powdered mineral components in layers between wool layers, using sodium silicate as an immobilisation material - suggest that further application tests using the mentioned application technologies, that were impossible due to their labour-intensive and expensive setting, are indispensable. The use of dry, hackled parts of moth repelling plants would be advantageous as a dry process and because of the omission of extraction technology. Yet so far it has been impossible to achieve adequate adhesion of the particles, and upscaling to a fully automated application seems impossible with state of the art technology for the production of felt from wool.
To achieve a fast realisation of the new moth composition for sheep's wool insulating materials and other household wool products and thus conserve sheep breeding and sheep's wool processing in Europe (who, without an alternative, would evade to non-EU-locations owing to the ban on Mitin) further research will be carried out after the completion of this project with new partners.
alchemia-nova Institut für innovative Pflanzenforschung
- Veronika Reinberg
- Brigitte Salcher
- Alfred Strigl
- Johannes Kisser
Project or cooperation partner
- Hubertus Kleeberg
Trifolio-M, Lahnau (D)
- Roland Meingast
natur & lehm, Tattendorf (NÖ)
- Alexander Lehner
Isolena, Waizenkirchen (OÖ)
- Walter Schober
Bioinnova, Heiligenkreuz (Bgl.)
- Michael Gross
- Anton Hagspiel
Hagspiel Naturbaustoffe, Doren (Vbg.)
- Harald Greger
Institut für Botanik, Universität Wien
- Wolfgang Harand
BION Verein zur Erforschung bioaktiver Naturstoffe
- Brigitte Brem, Elisabeth Kaltenegger
Verein zur Erforschung bioaktiver Naturstoffe und ihrer ökologischen Bedeutung (BION)
- Gerhard Karg
BUGS Kaiserslautern (D)
- Edmund Hummel
Trifolio-M, Lahnau (D)
- Andreas Greiner
FB Chemie Universität Marburg (D)
- Peter Laßnig
Biogärtnerei Gänserndorf (NÖ)
- Franz Neubauer
Ecolabor, Stainz (Stmk.)
- Helmut Pelzmann
Landwirtschaftliches Versuchszentrum Wies (Stmk.)
- Susanne Schemitz, Wien
- Josef Schett
Villgrater Naturprodukte, Josef Schett KG Innervillgraten Tirol
- Josef Spritzendorfer
Natureplus, Abensberg (D)
- Magdalena Reinberg
Reinberg Translations, Wien
- Vittorio Veronelli
CBC Europe, Mailand (Italien)