요소수지와 토난접착제 혼용이 합판의 접착력에 미치는 영향

이필우,박헌 한국목재공학회 1984 목재공학 Vol.12 No.1

Taro-UF mixed type resin system was developed for gluing plywoods. The taro adhesive that was activated with sodium hydroxide was mixed with the definite ratios of UF resin adhesive. At the sametime, wheat-UF mixed type resin was also applied with the same method as Taro-UF mixed type resin. The mixing ratios of taro or wheat adhesive: UF resin were 0:100, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 80:20, and 100:0 by weight. In addition, the UF resins extended with wheat powder at the extending ratios of wheat powder UF resin, 10:90, 20:80, 30:70, 40:60, and 50:50 by weight, were also used. The dry and wet shear strengths of the plywoods of 30:70 (taro adhesive : UF resin) mixing ratio were highest.. The dry shear strengths of the plywoods manufactured with the UF resin-mixing taro adhesive were higher than those of the plywoods with the UF resin-mixing wheat adhesive at 10:90, 20:80, 30:70, 40:60, 50:50, and 60:40 (taro or wheat adhesive : UF resin) mixing ratios. At all mixing ratios, the wet shear strengths of the plywoods manufactured with the UF resin-mixing taro adhesive were higher than those of the plywoods with the UF resin-mixing wheat adhesive. The dry and wet shear strengths of the plywoods manufactured with the UF resin-mixing wheat adhesive were higher than those of the plywoods with the wheat powder-extending UF resin at the mixing ratios, 10:90, 20:80, 30:70, and 40:60 (wheat adhesive or wheat powder : UF resin). So. it was found that the plywoods manufactured with the UF resin-mixing taro adhesive and the UF resin-mixing wheat adhesive had better shear strength than the plywoods with the wheat powder-extending UF resin. It was because the taro adhesive and wheat adhesive themselves took the bonding properties after being activated with alkali.

MDI 수지를 적용한 합판대용 박판상 복합재의 물리적·기계적 성질

이필우,김대준 한국목재공학회 1997 한국목재공학회 학술발표논문집 Vol.1997 No.-

대학재정과 세제 지원

이필우,Lee, Pil-U 한국대학교육협의회 1991 大學敎育 Vol.49 No.-

폴리프로필렌사칩과 배향사(配向絲)를 결재한 톱밥보드의 물리적 및 기술적 성질에 관한 연구

이필우,서진석 한국목재공학회 1988 목재공학 Vol.16 No.2

For the purpose of utilizing the sawdust having poor combining properties as board raw material and resulting in dimensional instability of board, polypropylene chip (abbreviated below as PP chip) or oriented PP thread was combined with sawdust particle from white meranti (Shores sp.). The PP chip was prepared from PP thread in length of 0.25, 0.5, 1.0 and 1.5 ㎝ for conventional blending application. Thereafter, the PP chip cut as above was combined with the sawdust particle by 3, 6, 9, 12 and 15% on the weight basis of board. Oriented PP threads were aligned with spacing of 0.5, 1.0 and 1.5㎝ along transverse direction of board. The physical and mechanical properties on one, two and three layer boards manufactured with the above combining conditions were investigated. The conclusions obtained at this study were summarized as follows: 1. In thickness swelling, all one layer boards combined with PP chips showed lower values than control sawdustboard, and gradually clear decreasing tendendy with the increase of PP chip composition. Two layer board showed higher swelling value than one layer board, but the majority of boards lower values than control sawdustboard. All three layer boards showed lower swelling values than control sawdustboard. 2. In the PP chip and oriented thread combining board, the swelling values of boards combining 0.5㎝ spacing oriented thread with 1.0 or 1.5㎝ long PP chip in 12 and 15% by board weight were much lower than the lowest of one or three layer. 3. In specific gravity of 0.51, modules of rupture of one layer board combined with 3% PP chip showed higher value than control sawdustboard. However, moduli of rupture of the boards with every PP chip composition did not exceed 80kgf/㎠, the low limit value of type 100 board, Korean Industrial Standard KS F 3104 Particleboards. Moduli of rupture of 6%, 1.5㎝-long and 3% PP chip combined boards in specific gravity of 0.63 as well as PP chip combined board in specific gravity of 0.72 exceeded 80kgf/㎠ on KS F 3104. Two layer boards combined with every PP chip composition shoewed lower values than control sawdustboard and one layer board. Three layer boards combined with 1.5㎝ lung PP chip in 3, 6 and 9% combination level showed higher values than control sawdustboare, and exceeded 80kgf/㎠ an KS F 3104. 4. In modules of rupture of PP thread oriented sawdustboard, 0.5㎝ spacing oriented board showed the highest value, and 1.0 and 1.5㎝ spacing oriented boards lower values than the 0.5㎝. However, all PP thread oriented sawdustboards showed higher values than control sawdustboard. 5. Moduli of rupture in the majority of PP chip and oriented thread combining boards were higher than 80kgf/em2 on KS F 3104. Moduli of rupture in the boards combining longer PP chip with narrower 0.5㎝ spacing oriented thread showed high values. In accordance with the spacing increase of oriented thread, moduli of rupture in the PP chip and oriented thread combining boards showed increasing tendency compared with oriented sawdustboard. 6. Moduli of elasticity in one, two and three layer boards were lower than those of control sawdustboard, however, moduli of elasticity of oriented sawdustboards with 0.5, 1.0 and 1.5㎝ spacing increased 20, 18 and 10% compared with control sawdustboard, respectively. 7. Moduli of elasticity in the majority of PP chip and oriented thread combining boards in 0.5, 1.0 and 1.5㎝ oriented spacing showed much higher values than control sawdustboard. On the whale, moduli of elasticity in the oriented boards combined with 9% or less combination level and 0.5㎝ or more length of PP chip showed higher values than oriented sawdustboard. The increasing effect on moduli of elasticity was shown by the PP chip composition in oriented board with narrow spacing. 8. Internal bond strengths of all one layer PP chip combined boards showed lower values than control sawdustboare, however, the PP chip combined boards in specific gravity of 0.63 and 0.72 exceeded 1.5kgf/㎠, the low Limit value of type 100 hoard and 3kgf/㎠, type 200 board on KS F 3104, respectively. And also most of all two, three layer-and oriented boards exceeded 3kgf/㎠ on KS F. 9. In general, screw holding strength of one layer board combined with. PP chip showed lower value than control sawdustboard, however, that of two or three layer board combined with PP chip did no decreased tendency, and even screw holding strength with the increase of PP chip composition. In the PP chip and oriented FP thread combining boards, most of the boards showed higher values than control sawdustbaard in 9% or Less PP chip composition.

건축재료연소시험기와 경사판 시험기를 이용한 합판의 내화도 (耐火度) 측정비교

이필우,권진헌 한국목재공학회 1982 목재공학 Vol.10 No.2

This experiment was carried out to evaluate the results of fire retardancy of sealer coated plywood by Building material combustibility tester and Inclined panel tester. At this study, weight loss percentage, flame exhausted time, burning point and smoke yield coefficient were examined. The findings of this study lead to conclusions as listed below. 1. It was obvious that weight loss percentage and flame exhausted time of Inclined panel tester had more remarkable tendency than those of Building material combustibility tester. 2. Burning point was determined by Inclined panel tester while smoke yield coefficient by Building material combustibility tester. 3. Weight loss percentage decreased remarkably with proportion to the increase of sealer coated amount during 5 minutes burning. 4. Flame exhausted time decreased with proportion to the increase of sealer coated amount during 3 minutes burning. 5. Burning paint indicated increasing tendency with proportion to the increase of sealer coated amount. 6. Smoke yield coefficient of urea sealer showed definite inclination decreasing with the increase of sealer coated amount.

1 , 2 , 3 Butt - joint 에 의한 들메나무 집성재의 휨성질에 미치는 butt 와 butt 거리의 영향

이필우,윤용원 한국목재공학회 1984 목재공학 Vol.12 No.5

A simple effect of butt to butt distances on the flexural properties of 1,2,3 butt-jointed glued beams fabricated by 3 laminations of Fraxinus mandshurica was studied on the conditions that the joints were separated in the middle lamination of each beam except control beams without joint in a longitudinal direction by a distance of t, a lamination thickness, and that the number of joint and the distance of butt to butt distances were; 0 t (1 joint); 10,20,30,35,40 t (2 joints); 5,10,15,17.5,20 t (3 joints). A pair of matched specimens, namely VLB (Vertically laminated beam) and HLB (Horizontally laminated beam). was made through each beam having joint and control beams without joint, both of beams were venter loaded to determine their MOR and MOE values. The results were summarized as follows; 1. Tensile failures were appeared at the tension parts of almost all HL.B and the VLB, both of which having joint; however, the difference of its mode on the load-deformation curve was little between VLB and HLB. 2. MOR values of VLB were slightly lower, but MOE vaiues of VLB slightly higher, than those corresponding values of HLB, on occasion of both control beams and 1 joint beams. 3. Within the range of butt to butt distances 10 to 40 t (2 joints) and 10 to 20 t (3 joints), it was obvious that the number of joint affected more serious decreasing effects of MOR than MOE values; however, the difference of the corresponding values of bath M()9 and MOE values was little between HLB and VLB bath of which have the same number of joint. 4. The results of regression relationships between MOR anti MOE values indicated that the MOE values of VLB be higher than those of HLB, if both beams have the same values of MOR.

한국산 산공재(散孔材)의 해부학적 특성에 관한 비교연구 (Ⅰ) : 단순상관과 주성분 분석에 의한 특성 Characteristics by Simple Correlation and Principal Component Analysis

이필우,정연집 한국목재공학회 1995 목재공학 Vol.23 No.4

The anatomy of Korean diffuse-porous woods. 36 families, 75 genera, 145 species, 215 specimens was described and analyzed. Sixteen wood anatomical characters, habit and phonology factors were determined by simple correlation and principal component analysis. Strong positive correlations were found between vessel element length and fiber length, ray width and ray height. simple pits of fiber wall and paratracheal parenchyma distribution. The results of principal component analysis (PCA) disclase the primitive characteristics and the direction of xylem evolution of Korean diffuse-porous wands. The xylem evolution scenario for Korean dicotyledonous woods is considered to be developed in the. direction of decreasing trends of vessel frequency, vessel element length, and length/diameter(L/D) ratio of vessel element but increasing trends of vessel diameter. fiber length/vessel element length(F/V) ratio, libriform wood fibers. simple perforation, and homogeneous ray composition. Increase of vessel diameter and decrease of vessel frequency seem to be related to the improvement of conductive efficiency, and increase of the vessel element length and occurrence of scalariform perforation in vessel element may be related to enhanced of conductive safety. Also the libriform wood fibers and ray features appear to have relationship with mechanical support and nutrient metabolism. respectively.

한국산 산공재의 해부학적 특성에 관한 비교연구 (Ⅱ) : Habit 과 Phenology 에 따른 특성 Characteristics by Habit and Phenology

이필우,정연집 한국목재공학회 1996 목재공학 Vol.24 No.1

The frequency distribution diagrams of Korean diffuse-porous woods. 36 families. 75 genera. 145 species. 215 specimens in relation to habit and phenology were analyzed. As the habit character changes from shrub to tree. such quantitative features as vessel frequency. percentage of solitary vessels, length/diameter(L/D) ratio of vessel element decreased but tangential vessel diameter. fiber length/vessel element length(F/V) ratio increased. Qualitative features such as helical vessel wall thickening, diffuse distribution of longitudinal parenchyma, heterogeneous ray composition decreased. while alternate intervessel pits, libriform wood fiber, simple perforations increase. As the phenology character changes from evergreen to deciduous species, such quantitative features as percentage of solitary vessels, vessel element length and L/D ratio decreased but tangential vessel diameter, F/V ratio increased. Diffusedistributionoflongitudinalparenchyma, heterogeneous ray composition, and crystals in qualitative features decreased, while alternate intervessel pits, libriform wood fiber, simple perforation of vessel element. ray width and ray height increased.

木材와 合板의 耐火處理에 關한 硏究/李弼宇

李弼宇,鄭希錫 서울大學校 農科大學 演習林 1980 서울大學校 農科大學 演習林報告 Vol.1980 No.16

유한요소법을 이용한 반강접합부의 구조해석모델

이필우,양한승 한국목재공학회 1995 목재공학 Vol.23 No.3

This study was carried out to develop a finite element analysis model that considers the semi-rigid characteristics of a wood-dowel joint. which is different from conventional joints that are used in the field of engineering. Wood-dowel joints are classified as semi-rigid joints that possess the following characteristics : (1) they are less stiffer than rigid joints and (2) their stiffness is determined by the dowel's diameter, depth of dowel embedment in the face member and quantity of pin dowels. In this study a finite element model that considers the changes in stiffness according to the above mentioned factors was developed and its suitability was verified by experiments using a wood-dowel joint test specimen made up of particleboards. After comparing the experimental results and the analysis results of the wood-dowel joint which was applied with the proposed finite element model. less than 10% of error was found which is considered to be negligibly small. Hence this shows that this proposed finite element model can be used to predict deformation of wood-dowel joints.