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.

수용성 아크릴 수지의 자외선 흡수제와 HALSS 첨가가 일본잎갈나무의 변색에 미치는 영향

이필우,강경택 한국목재공학회 1996 목재공학 Vol.24 No.4

UV transmission spectra of water-soluble acrylic resin films containing hydroxybenzophenolic, hydroxyphenylbenzotriazolic UV absorber and HALS(hindered amine light stabilizer) were investigated by exposure time(before exposure. weathered for 160 and 320hours) in QUV Weather-Ometer. Also the YID(yellowness index difference). LID(lightness index differences and CD(color difference) of dried water-soluble acrylic resin films and the coated moods of Larix leptolepis were analyzed by addition level of UV absorber(0, 1, 2 and 3%) and HALS(0, 0.5, 1 and 1.5%) and by exposure time in QUV Weather-Ometer. They showed no significant effects on UV transmission spectra of dried water-soluble acrylic resin films in the range of 300 to 400㎚ irrespective of exposure tune. However. UV transmission decreased as increase of exposure time. UV transmission spectra were lower in dried water-soluble acrylic resin films containing hydroxybenzophenolic UV absorber and HALS than in these containing hydroxyphenylbenzotriazolic UV absorber and HALS in the range of 350 to 400㎚. The least YID, LID and CD in the coated woods of Larix leptolepis appeared at the addition level of 3%, based an non-volatile content, in hydroxybenzophenolic and hydroxyphenylbenzotriazolic UV absorber, and of 1.5% in HALE to water-soluble acrylic resin.

갈색부후균 (Lentinus lepideus) 에 의해 부후된 소나무 재 (Pinus densiflora S . et Z .) 의 해부학적 특성

이필우,권미 한국목재공학회 1993 목재공학 Vol.21 No.1

The purpose of this study was to describe the micromorphological changes in Korean red pine (Pinus densiflora S. et Z.) wood decayed by a major brown-rot fungus, Lentinus lepideus, using scanning electron microscope and transmission electron microscope. At the end of the 12-week exposure to the fungus in soil block procedure(ASTM 1971), test blocks sustained 5.02% weight loss. The formation of bore hole by hyphae and penetration. of hyphae through bordered pit were riot observed. Instead, fungal hyphae appeared to penetrate axially tracheid luminar from the the ray cells via cross field pits. Hyphae were mainly found in lignin-rich cell corner regions of tracheids, and also extensive degradation of tracheid wall occurred in this region. Extensive degradation of S₂ layer occurred without noticeable alteration. of the S₃ layer, but warty layer and compound middle lamella remained relatively intact. Localized erosion, the characteristic of white rot, was observed in some cell wall and wall components including lignin were found to be decomposed.

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.

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

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.

대학재정과 세제 지원

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

한국산 옻칠도막에 관한 주사전기현미경적 고찰

이필우,김현중 한국목재공학회 1987 목재공학 Vol.15 No.3

This study was executed to investigate scanning electron microscopic characteristics of Korean Rhus lacquer coats. With the unrefined coat, distilled water, sodium hydroxide, acetic acid, ethyl alcohol, cold-check test, and accelerated weathering were performed after refining treatment. These treated lacquer coats were discussed through observation by scanning electron microscope and the obtained results were summarized as follows: 1. Compared with unrefined coat, the refined coat of Korean Rhus lacquer showed more even surface with regular distribution of dispression. 2. Korean Rhus lacquer coat heated at 120℃ for 3 hours revealed no observable difference irrespective of refining and unrefining 3. Korean Rhus lacquer coat treated by distilled after, sodium hydroxide, acetic acid, ethyl alcohol, cold-check test, and ultraviolet radiation showed significant characteristics compared with untreated coat. Especially, large deformation and checkings were observed by cold-check test and ultraviolet radiation, respectively. 4. The Korean Rhus lacquer coat radiated by ultraviolet ray showed 0.11 duller and 1.41 brighter than non-radiated coat through color difference calculator.

내화처리 (耐火處理) 파티클보오드의 내화도(耐火度)에 미치는 약제의 영향

이필우,권진헌 한국목재공학회 1983 목재공학 Vol.11 No.5

This research was performed to investigate the fire retarding properties of the particleboard formed with treated particles in the solutions of ammonium sulfate and Minalith, each of commercially important fire retardant chemicals. Laboratory test boards were made from particles treated by soaking in 5, 10, 15 and 20 percent concentration solutions of chemicals for 2 hrs. before resin was applied. According to the results, the Eire retarding effect of treated particleboard showed considerable difference compared with the untreated controlboard in weight lass, fingering flame time, burning paint, flame length and carbonized area. The boards treated with higher chemical concentrations indicated better results than lower. Minialith gave better results than chose obtained from the treatment of ammonium sulfate in weight loss, burning point, flame length and carbonized area, However no both chemicals gave significant difference in lingering flame time. Parallel and alternate veneer laminated products showed the same tendency as the untreated particleboard although they had a little difference.

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.