The Study of the Veneer Pretreatment with Aluminum Sulfate Solution on the Reduction of Urea Formaldehyde Resin Spreading Content for the Manufacture of Plywood

황산알미늄용액의 단판(單板) 전처리(前處理)에 따른 합판용(合板用) 요소수지(尿素樹脂) 도포량의 감소에 관한 연구(硏究)

This study was carried out to examine the effect of pretreatment of veneer with aluminum sulfate solution for the manufacture of the kapur plywood on the reduction of urea resin spread. The results were as follows: 1. Specific gravities of plywoods made of the kapur veneers ranged from 0.83 to 0.84 and their moisture contents based on air dry weight showed from 10.6% to 11.4%. These met the Korean Industrial Standards. 2. In the case of dry shear strength for the 3rd class plywood, 40% reduction- spread met K S as well as normal urea resin spread. pH of the aluminum sulfate solution gave better result at pH 4.5 and pH 6 than at pH 3. For the manufacture of the 2nd class plywood, hot and cold water-wet shear strength show the best results at the following conditions; such as 20% reduction spread, pH 4.5 of aluminum sulfate solution and all veneer treatment.