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

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

Abstract

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.

Keywords

• Colour,Heat-treatment,Varnish,ThermoWood

References

1. 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.
2. Hon, DNS (1991). Photochemistry of wood. In: Hon DN-S, Shiraishi N (eds) Wood and cellulosic chemistry. Marcel Decker, New York, pp 525 555.
3. 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.
4. 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.
5. Feist, W.C., (1983). Weathering and protection of wood. In: Annual meeting of the American wood-preservers’ association. Kansas 79: 195-205.
6. 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.
7. Sivonen, H., Maunu, S.L., Sundholm, F., Jämsä, S. and Viitaniemi, P., (2002). Magnetic resonance studies of thermally modified wood. Holzforschung, 56:648.
8. 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.

9. Mayes, D. and Oksanen, O., (2002). Thermo Wood Handbook; p. 52.
10. 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.
11. 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.
12. 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.
13. 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.
14. 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.