Study on Manufacture of Korean Paper(Hanji) Sludge-Wood Fiber Composite Boards II. Mechanical Properties of Korean Paper(Hanji) Sludge-Wood Fiber Composite Boards

한지슬러지-목재섬유 복합보드의 제조연구 II. 한지슬러지-목재섬유 복합보드의 기계적 성질

This study was carried out to develop the Korean paper(Hanji) sludge-wood fiber composite boards utilizing the relinquished sludges occurring from the making process of Korean classic paper Hanji. The bark of paper mulberry(Broussonetia kazinoki Sieb.) has been used as a raw material since past hundreds and thousands years. Korean paper(Hanji) sludge was divided into two kinds, the one was the white sludge from the first stage and the other was the black sludge occurring from the final stage of Korean paper(Hanji) making. Four levels of the mixed ratio of each white or black sludge to wood fiber(10:90, 20:80, 30:70 and 40:60), three levels of the resin adhesives(PMDI, urea and phenol resin) and three levels of the density(0.60, 0.75 and 0.90) were designed to investigate the mechanical properties of Korean paper(Hanji) sludge-wood fiber composite boards. From the results and discussion, it could be concluded as follows : 1. In the white and black sludge-wood fiber composite boards, bending modulus of rupture showed the clear decreasing tendency according to the increase of sludge additive, but it was clearly increased with the increase of specific gravity. Modulus of elasticity showed the same tendency as in the modulus of rupture, and also tensile and internal bonding strength had the same tendencies as in these bending properties. 2. Among the resin adhesives, PMDI or urea resin showed great values in MOR of white sludge-wood fiber composite board, but urea resin was greater than PMDI in MOR and MOE of black sludge-wood fiber composite board. Tensile and internal bonding strength showed the same tendencies as in white sludge-wood fiber composite board. 3. It is suggested that the white sludge-wood fiber composite boards bonded with PMDI or black sludge-wood fiber composite boards bonded with urea resin were able to made similar boards to general fiberboard by the mixed ratio 20:80 of sludge to wood fiber.

한지제지 공정 중에서 발생하는 백색슬러지와 흑색슬러지를 각각 일정비율(10:90, 20:80, 30:70, 40:60)로 목재 섬유와 혼합하고 PMDI, 요소 및 폐놀수지를 이용하여 목표비중 0.60, 0.75, 0.90 별로 복합보드를 제조한 결과 전반적으로 볼 때 PMDI수지를 적용한 백색슬러지-목재섬유 복합보드나 요소수지를 적용한 흑색슬러지-목재섬유 복합보드의 경우 20% 정도까지의 슬러지 첨가는 거의 통상적인 보드에 대용하는 기계적 성질을 지닌다고 믿어진다.