Proceedings of the 51st International Convention of Society of Wood Science and Technology November 10-12, 2008 Concepción, CHILE Paper WS-26 1 of 4 Internal Bond Strength of Laminated Flooring as Function of Water Exposure Salim Hiziroglu Department of Natural Resources Ecology and Management Oklahoma State University Stillwater, Oklahoma,USA Abstract Laminated flooring is widely used in many European countries over 20 years and getting more popular in North America having an important market share of flooring industry. A wear resistance decorative paper usually saturated with melamine base resin is used in the core of overlay paper for laminated flooring manufacturing. Durability of laminated panels against moisture exposure is one of the most important properties of such panels. In this study commercially manufactured high density fiberboard (HDF) based laminated samples were exposed to a sequence of 2 hrs, 24 hrs and 15 days water soaking test. Internal bond (IB) strength from 2 in by 2 in by 0.25 in samples was determined at each exposure level. All of the failures took place in the core layer of the specimens. Based on initial results of this work IB strength of the samples reduced from an average value of 340 psi to 300 psi as a result of 2-hr water exposure. When the samples were kept in water for 24 hrs and 15 days their IB strength reduction was not substantial. It appears that 24 hrs water soaking exhibited the maximum damage on IB strength characteristics of the samples. No statistical significant difference between IB values of the samples exposed to water soaking for 24 hrs and 15 days was determined at 95% confidence level. This may suggest that IB strength values of the samples were not influenced with an extension of water exposure time beyond 24 hrs. Samples also did not exhibit any delamination following the soaking test. In further studies other properties including bending strength and hardness of the samples would be evaluated to have a better information about influence of water exposure on properties of laminated flooring panels. Keywords: Internal bond strength, laminated flooring, HDF, water exposure.