Use of spruce tannin as a binder in particleboards and medium density fiberboards (MDF)

Abstract

In the recent past, increasing attention has been paid to the use of natural adhesives as a binder in the wood-based panel industry. Nowadays, two German companies are using Quebracho tannin and Wattle tannin for the production of particleboards and medium density ®berboards (MDF), respectively. To date no serious attention has been given to bond ®berboards using tannin derived from spruce bark. Results of research work on the use of spruce tannin as a binder for medium density ®berboards carried out in the last two years are presented. The results reveal that spruce tannin can be used to partially substitute Quebracho tannin in MDF up to about 60%. Such boards still meet the speci®cation of moisture resistant MDF (according to EN 319 and EN 321). Moreover, spruce tannin can be used to 100% as a binder for the production of MDF for indoor use (type MDF EN 622-5). Fichten-Tannin alsKleber fu Èr Spanplatten und MDF Seit kurzem wird natu Èrlichen Klebern als Bindemittel fu Èr Spanplatten auch in der Industrie erho Èhte Aufmerksamkeit gewidmet. Zur Zeit verwenden zwei deutsche Firmen Quebracho-und Akazientannin fu Èr die Produktion von Spanplatten und MDF. Bisher wurden Tannine aus Fichtenrinde hierfu Èr noch nicht ernsthaft in Betracht gezogen. Die vorliegende Arbeit stellt Ergebnisse eines Forschungsprojektes zur Verwendung von Fichtentannin fu Èr MDF vor. Mit Fichtentannin kann bis zu 60% des Quebrachotannins in MDF ersetzt werden. Solche Platten erfu Èllen die Richtwerte der EN 319 und 321 fu Èr die Feuchteresistenz. Daru Èberhinaus kann bei Platten fu Èr Innenverwendung (Typ EN 622-5) bis zu 100% Fichtentannin verwendet werden. IntroductionUtilization of bark is one of the utmost pressing problems facing the wood industry. The quantities of bark available are substantial, since approximately 10±15% of the volume of every log consists of bark. In Germany, about 2 million tons of bark are produced annually. Dealing with such enormous quantities of bark has created thorny disposal problems, particularly with the outcome of more stringent environmental regulations regarding air and water pollution enacted in the recent past. It has become imperative that the industry no longer considers bark as a waste. Bark is a low cost material with a limited market for diverse applications such as a high-quality mulch or as energy source. However, the current uses do not require bark in suf®cient quantities to consume the supply available.Bark and heartwood of limited wood species contain large quantities of water soluble extractives of polyphenolic nature suitable as a starting material for the production of adhesives. The extractives are mainly concentrated in the inner layer of the bark (Fig 1). Figure 2 shows the extractable amounts by water at about 100°C from different barks and wood species. In general the hot water extract of bark or heartwood comprise about 60±80% of polyphenolic tannin polymers as measured by the so called``hide powder'' method. The remainder is a mixture of many polymeric and monomeric compounds, such...

Effects of Pinus pinaster bark extracts content on the cure properties of tannin-modified adhesives and on bonding of exterior grade MDF

“…Therefore, it is reasonable to assume that similar adhesive systems could be used for bonding medium density berboards (MDF). Researchers have described the application of other tannin adhesives for industrial MDF and particleboard manufacture; for example, Roffael et al [2] employed quebracho and wattle tannin adhesives for the production of particleboards and MDF in Germany, and Trosa and Pizzi [3] prepared MDF and particleboards with quebracho tannin adhesives.…”

Physico-mechanical properties of particleboards bonded with pine and wattle tannin-based adhesives

“…The major species from which it can be obtained are Mimosa, Quebracho and Radiata Pine. It is mainly concentrated in the inner layer of the bark and has been used in the adhesive industry in Africa, South America and Oceania to obtain the low formaldehyde emission levels required for environmental-friendly adhesives [6,7].…”

Karakterisasi busa kaku (rigid foam) yang dihasilkan dari bubuk gambir (Uncaria gambir Roxb.) dengan bubuk albumin

“…Gambir (Uncaria gambir Roxb) adalah tanaman dengan komponen utamanya berupa katekin dan tanin (Kasim, 2011). Tanin juga dapat digunakan sebagai agen untuk mengikat partikel dan fiber boards (Roffael et al, 2000) serta juga dapat digunakan dalam pembuatan busa sebagai bahan isolator (Tondi and Pizzi, 2009 ;Lagel et al, 2014). Beberapa tahun terakhir, busa berbasis tanin diperoleh dari 95 % substrat alami.…”