• Journal of the Korea Furniture Society
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• v.14 no.2
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• pp.1-12
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• 2003

This study was carried out to determine the mechanical and physical properties of particle boards glued with condensed tannin (Wattle Tannin) powder that was single-molecule phenolic compounds like powdered phenolic resin. Our findings are; 1) It is necessary to spray water on the chip surfaces for effective application of powdered -form tannin resin. It shows that the best and optimum mat moisture increase is 14% of water spray on the surface of chips for developing PB properties. 2) In general, for both liquid and powdered tannin adhesives, their physical and mechanical properties has been proportional to the increase of resin level. But, the most efficient addition ratio is 16% of resin on dry basis. Specially, it is found that the resin level influences on the amount of free formaldehyde emission. The higher the resin level is, the lower the emission is. These phenomena seem to result from the increase of hexamine or formaline in the adhesives used as a hardener, that reduce the free-formaldehyde amount by reaction of tannin of poly-molecule and water. 3) The optimum condition for manufacturing PBs is the condition of hexamine of 5% and formaline of 6% in mechanical and physical properties. Hexamine is superior to formaline in mechanical and physical properties along with the control of the free formaldehyde emission amount. The result of NaOH's addition is insignificant in all experiments of both mechanical and physical properties.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.80-87
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• 2004

This study was carried out to improve the properties of powdered tannin adhesive(PT) by adding liquid tannin resin(LT) to PT in the manufacture of particleboard. Mixing the LT to PT from 50% to 100% by weight did not show any difference in particleboard properties, but the higher the powdered tannin resin ratio, the lower the properties of the board. The proper ratio of PT to LT was 30:70 for the improvement of PT-particleboard, unless LT lower than 70%. Internal bonding strength was in proportional to the amount of LT. Mixing amino adhesives and PT did not show any improvements in mechanical and physical properties of the board but they only acted as scavenger for the free formaldehyde.Manufacturing particle board with the adhesive of 30:70 (PT:LT) and by using double blender resulted in high-performance products of E₀ level of formaldehyde emission with high water resistance (U type; below 12%, M type; below 25%), as well as saving chip drying energy.