Abstract
Water proofing effect of paraffin wax, varied in melting point, treated on sapwood of Cryptomeria japonica were evaluated for hygroscopic swelling, water repellency and its durability. Results obtained, were as follows.
1) Hygroscopic swelling was not stopped by impregnation of paraffin wax but swelling rate alone was delayed.
2) Contact angle of water on the paraffin-treated wood was about 120°. On paraffin-coated wood, water repellency effect was reduced by cutting out the surface layers of wood, supposed the abrasion in outdoor use. However, water repellency recovered when surface temperature went up more than melting point of paraffin, supposed the irradiation of sunshine.
3) Durability of water repellency of paraffin-coated wood in outdoor weathering was related to the melting point of paraffin wax. Optimum melting point of paraffin was 60-62°C.
