EFFECTS OF HEAT-TREATMENT AND VARNISH APPLICATION ON THE COLOUR CHANGE OF PINE AND ASH LAMINATED VENEER LUMBERS

Yıl 2019, Cilt: 8 Sayı: 2, 28 - 34, 31.12.2019

Sema Aysal Keskin Hamiyet Şahin Kol Kübra Gündüz Vaydoğan

Öz

Heat treatment temperatures and
varnish effects on colour properties of pine (Pinus sylvestris L.) and ash (Fraxinus
americana) laminated veneer lumbers (LVL) were evaluated. In the first
instance the wood lumbers were exposed to heat treatment with the temperatures
of 190 and 212 ºC for 1.5 and 2 h, respectively. After heat treatment process,
LVLs were manufactured from heat treated pine and ash veneers with polyurethane
(PU) and melamine urea –formaldehyde (MUF) adhesives and one surface of them
varnished with yacht varnish. A spectrophotometer was employed to determine
colour change of heat-treated and varnished specimens. The samples had
significant discoloration as a result of heat exposure and varnish application.
Colour difference of the specimens increased as a result of all treatment
temperatures. Varnish application caused a significant colour change for both
tree species.

Anahtar Kelimeler

Colour, Heat-treatment, Varnish, ThermoWood

Destekleyen Kurum

Scientific Research Project Department of Karabuk University

Proje Numarası

KBÜ-BAP-14/2-DS-045

Teşekkür

Thanks to Scientific Research Project Department of Karabuk University due to the contributions.

Lamine Edilmiş Çam ve Dişbudak Levhalarının Renk Değişimi Üzerine Isıl işlem ve Verniğin Etkisi

Öz

Isıl işlem sıcaklığı ve  verniğin, çam (Pinus sylvestris L.) ve dişbudak (Fraxinus americana) lamine edilmiş levhalarının (LVL) renk özellikleri üzerindeki  etkileri değerlendirilmiştir. İlk olarak, çam ve dişbudak keresteleri, sırasıyla 1,5 ve 2 saat boyunca 190 ve 212 ºC sıcaklıklarda ısıl işleme maruz bırakılmıştır. Isıl işlemden sonra LVL'ler, ısıl işlem görmüş çam ve dişbudak kerestelerinden elde edilen tabakalar poliüretan (PU) ve melamin üreformaldehit (MUF) tutkalları ile yapıştırılarak üretilmişlerdir ve bir yüzeyleri yat verniği ile verniklenmiştir. Isıl işlem görmüş ve verniklenmiş numunelerin renk değişimini belirlemek için bir spektrofotometre kullanılmıştır. Numunelerde, ısıya maruz kalma ve vernik uygulamasının sonucu olarak belirgin renk değişimi görülmüştür. Numunelerin renk farkı, tüm işlem sıcaklıkları nedeniyle artmıştır. Vernik uygulaması, her iki ağaç türü için de önemli bir renk değişikliğine sebep olmuştur.

Anahtar Kelimeler

Renk;, Isıl işlem, vernik, thermowood

Proje Numarası

KBÜ-BAP-14/2-DS-045

Kaynakça

• Williams, R.S., (2005). Weathering of wood. In: Rowell, R.M. (ed) Handbook of wood chemistry and wood composites. CRC Press, Florida, pp. 139-185.-163.
• Hon, DNS (1991). Photochemistry of wood. In: Hon DN-S, Shiraishi N (eds) Wood and cellulosic chemistry. Marcel Decker, New York, pp 525 555.
• Evans, P.D., Michell, A. J. and Schmalzl K.J., (1992). Studies of the degradation and protection of wood surface. Wood Science Technology; 126:151.
• Hon, D.,N.,S., (2001). Weathering and photochemistry of wood. In: HON, D. N.-S.; SHIRAISHI, N. (eds) Wood and cellulosic chemistry. Marcel Dekker, New York, pp. 513-546.
• Feist, W.C., (1983). Weathering and protection of wood. In: Annual meeting of the American wood-preservers’ association. Kansas 79: 195-205.
• Ayadi, N., Lejeune, F., Charrier, F., Charrier, B. and Merlin, A., (2003). Color stability of heat-treated wood during artificial weathering. Holz als Roh-und Werkstoff, 61(3), 221-226.
• Sivonen, H., Maunu, S.L., Sundholm, F., Jämsä, S. and Viitaniemi, P., (2002). Magnetic resonance studies of thermally modified wood. Holzforschung, 56:648.
• Syrjänen, T. and Kangas, E., (2000). Heat treated timber in Finland. The International research group on wood Preservation, IRG/WP 00e40158. IRG Secretariat; SE-100:44.
• Mayes, D. and Oksanen, O., (2002). Thermo Wood Handbook; p. 52.
• ASTM D3023-98, (2011). Standard Practice for Determination of Resistance of Factory-Applied Coatings on Wood Products to Stains and Reagents. American Society for Testing and Materials, USA.
• Bekhta, P. and Niemz, P., (2003). Effect of high temperature on the change in color, dimensional stability and mechanical properties of spruce wood. Holzforschung, 57(5), 539-546.
• Sundqvist, B., (2002). Color response of Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and birch (Betula pubescens) subjected to heat treatment in capillary phase. European Journal of Wood and Wood Products, 60(2), 106-114.
• Şahin, H.T. and Korkut, S., (2016). Surface colour changes of turkish hazelnut wood caused by heat treatment. Journal of Advances in Biology & Biotechnology, 6(1): 1-7.
• Pelit, H., (2017). The effect of different wood varnishes on surface color properties of heat treated wood materials. İstanbul Üniversitesi Orman Fakültesi Dergisi, 67(2), 262-274.