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Extraction and characterization of bark tannin from domestic softwood species for bonding applications in wood-based materials

English title Extraction and characterization of bark tannin from domestic softwood species for bonding applications in wood-based materials
Applicant Pichelin Frédéric
Number 136559
Funding scheme NRP 66 Resource Wood
Research institution Berner Fachhochschule Architektur, Holz und Bau
Institution of higher education Berne University of Applied Sciences - BFH
Main discipline Material Sciences
Start/End 01.04.2012 - 30.09.2015
Approved amount 400'000.00
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All Disciplines (2)

Discipline
Material Sciences
Organic Chemistry

Keywords (8)

bark; chemical characterization; formaldehyde-free wood-based products; wood based materials; extraction; domestic softwoods; tannin; green adhesive

Lay Summary (German)

Lead
Extraktion von Tanninen aus Rinden heimischer Nadelhölzer In diesem Projekt entwickeln die Forschenden einen Extraktionsprozess zur Gewinnung von Tanninen aus den Rinden heimischer Nadelhölzer. Bislang fehlt für die Rinde eine geeignete Lösung für eine gewinnbringende stoffliche Nutzung. Die gewonnenen Tannine sollen in emissionsarmen Klebstoffsystemen zur Herstellung von Holzwerkstoffen wie Brettschichtholz, Spanplatten oder Furniersperrholz eingesetzt werden.
Lay summary

Hintergrund
Bei der Herstellung von Holzwerkstoffen sind Tannine eine mögliche Komponente der dafür notwendigen Klebstoffsysteme. Bislang werden kommerziell gehandelte Tannine aus Holz oder Rinde tropischer oder subtropischer Holzarten wie Quebracho (Schinopsis balansae) oder Mimosa (Acacia mearnsii) extrahiert. Die Extraktion des natürlichen Gerbstoffs Tannin erfolgt dabei üblicherweise in wässrigen alkalischen Lösungen. Nach Sprühtrocknung kommen die in den Extrakten enthaltenen Tannine in Pulverform weltweit in den Handel. Rinden europäischer Nadelhölzer werden bislang nicht zur kommerziellen Tanningewinnung eingesetzt, obwohl Versuche im Labor bereits gezeigt haben, dass z.B. Tannine der Fichtenrinde (Picea abies) zur Herstellung von Klebstoffsystemen geeignet sind.

Ziel
Vorrangiges Ziel des Projekts ist es, einen Extraktionsprozess zu entwickeln, der zur Gewin-nung von Tanninen aus heimischen Nadelholzrinden geeignet ist und in bestehende Prozesse von Sägewerken und holzverarbeitenden Industrien integriert werden kann. Dabei gilt es zu wissen, welchen Einfluss einzelne Extraktionsparameter auf die chemische Struktur und Eigenschaften der extrahierten Tannine haben. Zusätzlich formulieren die Forschenden formaldehydfreie Klebstoffe auf Basis der gewonnenen Tannine und analysieren die physikalischen und mechanischen Eigenschaften der daraus hergestellten Holzwerkstoffe. Neben den chemisch-technischen Aspekten evaluieren die Forschenden die Wirtschaftlichkeit des entwickelten Extraktionsprozesses unter Berücksichtigung des Rohstoffaufkommens der Rinden in der Schweiz.

Bedeutung
Der angestrebte Extraktionsprozess und die weitere Verwendung der Tannine in Klebstoffsys-temen zur Holzwerkstoffherstellung sollen die Wertschöpfung der Rinde massgeblich verbessern und eine echte Kaskadennutzung ermöglichen. Der Einsatz der Tannine in formaldehydfreien Klebstoffsystemen würde zudem ihre Vermarktung im Bereich der zunehmend nachgefragten, besonders emissionsarmen Holzwerkstoffe ermöglichen.

Direct link to Lay Summary Last update: 25.01.2013

Lay Summary (French)

Lead
Extraction de tanins de l’écorce de résineux indigènes Les chercheurs de ce projet travaillent au développement d’un procédé d’extraction des tanins à partir des écorces de résineux indigènes. A ce jour, il manque encore une solution appropriée pour l’exploitation rentable de l’écorce comme matière première. Les tanins ainsi obtenus sont destinés à des systèmes de colles à faible émission pour fabriquer des bois lamellés-collés, agglomérés et autres placages.
Lay summary

Contexte
A ce jour, les tanins proviennent du bois ou de l’écorce d’essences tropicales ou sub-tropicales telles que le quebracho ou le mimosa. L’extraction du tanin naturel se fait généralement dans des solutions alcalines aqueuses. A l’issue d’un processus de séchage par atomisation, les tanins sont commercialisés à l'échelle mondiale sous forme de poudre. A ce jour, l’écorce des résineux européens ne servent pas à l’extraction commerciale du tanin, bien que des expériences en laboratoire ont prouvé que certains tanins, notamment ceux extraits de l’écorce d’épicéa, se prêtaient à la fabrication de systèmes de colles.

But
L’objectif premier du projet est la mise au point d’un procédé d’extraction adapté à l'extraction de tanins des résineux indigènes et pouvant être intégré aux processus existants dans les scieries et les industries de transformation du bois. A cet effet, il faut connaître l’influence exercée par chacun des paramètres d’extraction sur la structure chimique et sur les propriétés des tanins extraits. De plus, les chercheurs formulent des colles sans formaldéhyde sur la base des tanins extraits et analysent les propriétés physiques et mécaniques des dérivés du bois ainsi fabriqués. Outre les aspects chimiques et techniques, les chercheurs évaluent la rentabilité du processus d’extraction mis au point, en tenant compte de la disponibilité en Suisse de la matière première, l’écorce.

Portée
Le processus envisagé pour l’extraction des tanins, et leur utilisation en aval dans des systèmes de colles en vue de la fabrication de produits dérivés du bois, a vocation à améliorer considé-rablement la valorisation de l’écorce et à amorcer une véritable utilisation en cascade. En outre, l’utilisation des tanins dans les systèmes de colles sans formaldéhyde permettrait la commercialisation de celles-ci dans le domaine des dérivés du bois à faibles émissions, dont la demande est croissante.

Direct link to Lay Summary Last update: 25.01.2013

Lay Summary (English)

Lead
Extraction of tannins from the bark of local conifers In this project, researchers develop an extraction process for gaining tannin from the bark of local conifers. There is still no suitable solution for a profitable exploitation of the bark until now. The tannins gained are to be used in low-emission adhesive systems for the production of wood-based materials, such as glued laminated timber, particleboards or veneer plywood.
Lay summary

Background
Tannins are a possible component of the adhesive systems needed to produce wood-based materials. Until now, commercially traded tannins have been extracted from the wood or bark of tropical or subtropical wood types, such as quebracho (schinopsis balansae) or mimosa (acacia mearnsii). The extraction of the natural tanning agent tannin is generally done via watery alkaline solutions. After spray drying, the tannins contained in the extracts are offered for sale all over the world in powder form. The barks of European conifers have so far not been used for commercial tannin extraction even though experiments in the laboratory have shown that, e.g., tannins from spruce bark (picea abies) are suitable for producing adhesive systems.

Aim
The main aim of the project is to develop a suitable process for extracting tannins from local conifer barks. It should be capable of being integrated into processes already in place in sawmills and wood-based industries. In this context, it is important to consider the influence of individual extraction parameters on the chemical structure and properties of the extracted tannins. The researchers also formulate formaldehyde-free adhesives on the basis of the extracted tannins and analyse the physical and mechanical properties of the resultant wood-based materials. Alongside the chemical-technical aspects, the researchers also evaluate the economic viability of the new extraction process while taking into account the supply of bark as a raw material in Switzerland.

Significance
The envisaged extraction process and the further use of the tannins in adhesive systems for the production of wood-based materials are aimed at significantly improving the added value of the bark and at enabling real cascade use. The use of tannins in formaldehyde-free adhesive systems would moreover enable them to be marketed as increasingly sought after and particularly low-emission wood-based materials.

Direct link to Lay Summary Last update: 25.01.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Characterization of condensed tannins and carbohydrates in hot water bark extracts of European softwood species
Bianchi Sauro, Kroslakova Ivana, Janzon Ron, Mayer Ingo, Saake Bodo, Pichelin Frédéric (2015), Characterization of condensed tannins and carbohydrates in hot water bark extracts of European softwood species, in Phytochemistry, 120, 53-61.
Analysis of the structure of condensed tannins in water extracts from bark tissues of Norway spruce (Picea abies [Karst.]) and Silver fir (Abies alba [Mill.]) using MALDI-TOF mass spectrometry
Bianchi Sauro, Alexia Glöss, Kroslokova Ivana, Mayer Ingo, Pichelin Frédéric (2014), Analysis of the structure of condensed tannins in water extracts from bark tissues of Norway spruce (Picea abies [Karst.]) and Silver fir (Abies alba [Mill.]) using MALDI-TOF mass spectrometry, in Industrial Crops and Products, 61, 430-437.
Hot water extraction of Norway spruce (Picea abies [Karst.]) bark: analyses of the influence of bark aging and process parameters on the extract composition
Bianchi Sauro, Koch Gerald, Janzon Ron, Mayer Ingo, Saake Bodo, Pichelin Frédéric, Hot water extraction of Norway spruce (Picea abies [Karst.]) bark: analyses of the influence of bark aging and process parameters on the extract composition, in Holzforschung.

Collaboration

Group / person Country
Types of collaboration
University of Hamburg Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
WoodChem2013 Poster Methods for the chemical characterization of water soluble phenolic compounds from bark tissue of some European softwood species 26.09.2013 Strasbourg, France Pichelin Frédéric; Kroslakova Ivana; Bianchi Sauro; Mayer Ingo;


Knowledge transfer events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
11. Holzwerkstoff Kolloquim 11.12.2015 Dresden, Germany


Self-organised

Title Date Place
Dialog Plattform Innovative wood-based materials 25.09.2015 Biel, Switzerland

Awards

Title Year
Materialica Design Award 2012

Associated projects

Number Title Start Funding scheme
177480 PINOY Tannin (Full) 01.06.2018 r4d (Swiss Programme for Research on Global Issues for Development)

Abstract

The aim of this project is the development of a tailor-made extraction process for bark tannins from domestic softwood species focussing on the use of the tannins as adhesives in wood-based materials production. Bark as by-product in the wood-processing industry is missing a profitable commercialisation for large scale amounts so far. The combustion for energy production and the biodegradation after horticulture utilisation are the two established ways of valorisation. A chemical valorisation would be much more adapted, when taking in account the presence of polyflavonoid condensed tannins, main constituents of tannin-based adhesives. The total amount of bark from Swiss wood is approximately 170’000 tons/year, expecting a relevant potential of bark in Switzerland that could be used for the drafted utilization.First objective is the development of a tailor-made tannin extraction process that can be implemented in the material flow of existing industrial processes (e.g. sawmills) in central Europe (selective extraction of bark compounds due to their polarity and solvability). A second objective is the production of formaldehyde-free adhesives based on tannins from domestic softwood bark.The bark extracts from Norway spruce (Picea abies), Pine (Pinus sylvestris), European larch (Larix decidua), European silver fir (Abies alba) and Douglas fir (Pseudotsuga menziesii) and their tannin fractions in particular will be investigated dependent from extraction process parameters. The influence of extraction parameters on chemical structure and properties of the extracted tannins will be evaluated in detail. An optimized and economically beneficial extraction process for the production of bark tannins for application as adhesive for the production of formaldehyde-free wood-based materials will be developed. Combinations of different tannin extracts are investigated to tailor the adhesive system for the special requirements of the wood-based material production. The tannin-based adhesive systems are applied for board production in laboratory scale and the physical and mechanical propertied of the boards are evaluated. Economical aspects of bark extraction, industrialization, commercialization, and local and regional supply networks are evaluated. Value-adding production of quality tannins from bark of domestic softwood species by a cost-effective extraction process, implemented in the material flow of existing wood industry processes (no transportation costs, use of local raw material), will offer Switzerland a leading position in the field of bark valorisation and green adhesives. This project will also offer new business opportunities to the sawmill and wood-based panel industry.
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