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.

제이인산 암모늄에 의한 합판의 내화처리 (Ⅰ) - 온냉침지처리와 (溫冷浸漬處理) 열판에 의한 처리합판의 재건조 -

이필우,정우양 ( Phil Woo Lee,Woo Yang Chung ) 한국산림과학회 1983 한국산림과학회지 Vol.60 No.1

Plywood, the representative interior decorative or structural material, is so inflammable that it may cause big fires. Therefore, it is required inevitably to manufacture the $quot;Fire retardant treated plywood$quot;, and it will be a study on the redrying of treated plywood that we ought to solve. This study was carried out to investigate the absorption of 20% (NH₄)₂HPO₄ solution into the soaked plywoods by hot/cold soaking for 3/3, 6/3, 9/3 and 12/3 hours and to study drying process with drying curves and drying rates by press-drying at the platen temperature of 130, 145, 160 and 175℃. Solution absorption of plywoods in hot/cold soaking method increased steadily with the prolonged soaking time, and water absorption is higher than DAP absorption, and then chemical retention (DAP) exceeded the minimum retention [ 1.125 Kg/(30㎝)³] even in the shortest soaking treatment. Drying curves of water-soaked plywoods inclined more steeply than those of DAP soaked plywoods. And the drying proceeded rapidly with the increase in platen temperature and terminated in 2.51 minutes at the temperature of 160 and 170℃. Drying rate also increased generally with the increase of platen temperature. So it was at 175℃ in DAP-soaking and at 160℃ in water-soaking when the drying rate became above 10%/min.

서평 : “경제신화: 정통경제학의 10대 오류” D. 오렐 저 (Icon Books, 2010)

이필우 한국경제학회 2011 한국경제포럼 Vol.4 No.1

Nicholas Kaldor의 An Expenditure Tax

이필우 한국경제학회 2012 한국경제포럼 Vol.5 No.2

졸참나무 지재 (枝材) 섬유에 관한 연구

이필우,엄영근 ( Phil Woo Lee,Young Guen Eom ) 한국산림과학회 1983 한국산림과학회지 Vol.60 No.1

According to the worldwide decreasing tendency in raw materials and increase in wood demands since 1970, the efficient utilization of raw materials was required internationally. Therefore this study dealt with the dimensional characteristics of branchwood fiber of Ouercus serrata Thunb for the complete utilization of whole tree. According to the branch individuals, parts and positions within a tree, fiber length, width and wall-thickness were measured. The results obtained are as follows: 1) As the height of individual branchwood increases from ground toward, fiber length and width, and wall-thickness decreased linearly and their regression equations obtained, were Y=770.03-22.643X, Y=27.444-0.71385X and Y=12.308-0.57320X respectively 2) From the main stem to branch in distal direction, fiber length, width and wall-thickness linearly decreased and their regression equations obtained were Y=752.70-0.6724X, Y=26.152-0.0084867X and Y=11.258-0.006205X, respectively. 3) As the radial direction from pith to hark increases, fiber length, width and wall-thickness increased linearly and their regression equations obtained were Y=679.73+11.231X Y=25.382+0.0925X and Y=10.521+0.11787X, respectively. 4) Mean value of fiber length, width and wall-thickness were 625-765, 26 and 11㎛, respectively.

競爭에 관한 東西 思想 比較 硏究

이필우 建國大學校 經濟經營硏究所 1998 商經硏究 Vol.23 No.1

PVC 앵커와 나사못으로 구성한 가구류 접합부의 강도

이필우,박희준 한국목재공학회 1991 목재공학 Vol.19 No.1

This study was carried out to determine the joint characteristic of L-type specimens. L-type specimens were made of two kinds cf solid woods(Antiaris, Sepetir) and three kinds of wood based materials(plywood, particleboard, medium density fberboard). They were constructed with PVC anchor and screw, and were discussed with joint strength and stiffness coefficients. The obtained results were as follows: 1. Bending strength showed very high increasing rate from one to three used PVC anchor and screw but was a little rise from three to four used PVC anchor and screw in solid wood. However, in wood based materials, it was unchanged without increasing rate or slight decreased from three to four used PVC anchor and screw. 2. The stiffness coefficients, or Z-values, were in the range from 4.704×10^(-4) to 1.864 ×10^(-3) ³(rad/kgf-㎝). They showed 10^(-3) level in one PVC anchor and screw but 10^(-4) level in two, three, four PVC anchor and screw. Accordingly. they indicated flexible joints in one PVC anchor and screw and relatively stable joints in two, three, four PVC anchor and screw. 3. Measured ultimate bending moments were 258.70kgf-㎝ in plywood and 142.68kgf-㎝ in medium density fiberboard. 4. Comparing with dowel joint, the joint strength used PVC anchor screw was inferior to 8㎜ and 10㎜ dowel diameter but differ little from 6㎜ dowel diameter.

Improvement of sensor sensitivity by mechanical buckling on polycarbonate substrate

이필우,이현호,정헌상,강원규,우경민,신호철 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0

In resent years, surface modifications on biosensors are studied in some trials. Especially, surface bucklings by mechanical force have received significant attentions due to their simplicities and substrate specificity. Through the buckling, the sensitivity enhancement can be allowed to cover low concentrations of target material. The higher sensitivity, the faster treatment can be. Substrate patterning could be obtained by using machanical bukling. In this study, the machanical bukling could make wrinkles on the surface of polycarbonate(PC). Additionally with the stretch of PC, treatment with ultraviolet-Ozone & wash was adopted. To check wrinkles, Alpha-step for micro-scaled wrinkles and AFM for nano-scaled wrinkles were used. By using XRD spectroscopy, the full width at half maximum(FWHM) was measured to confirm whether semi-crystallity of the PC has been changed.

합판용 요소 , 요소 메라민 공축합 (共縮合) 및 수용성 석탄산수지 (石炭酸樹脂) 접착의 증량에 관한 연구

이필우,권진헌 ( Phil Woo Lee,Jin Heon Kwon ) 한국산림과학회 1980 한국산림과학회지 Vol.48 No.1

This research was carried out to examine the substitutional feasibility of low-priced materials produced in waste of forest instead of wheat flour which is extended for plywood adhesives. Wheat, pine bark, wood flour and pine foliage of coniferous trees or poplar foliage of hardwood species were selected and pulverized into 60-100 mesh minute powder after they were dried at 100-105℃ during 24 hours in the drying oven. The prepared particles as above were added to urea formaldehyde resin, urea-melamine copolymer resin and water soluble phenol formaldehyde resin in the ratio of 10, 20, 30 and 50%. After plywoods were processed by the above extending ratios, shear strength of extended plywoods were analyzed and discussed. The results obtained at this study were summarised as follows; 1. In the case of urea formaldehyde resin, both dry and wet shear strength of plywoods extended by wheat flour were shown the highest value. 2. Dry shear strength of urea-melamine copolymer resin was better than that of urea formaldehyde resin on the whole, while plywoods extended by wheat flour were shown excellent results. 3. Among 10% and 20% extensions of urea-melamine copolymer resin, the best results were shown by poplar leaves powder, wheat powder and wood flour. They had no significant difference statistically. 4. In the case of water soluble phenol formaldehyde resin, although dry shear strength of pine leaves powder was higher than that of wheat flour in the ratio of 10%, there was no significant difference between them in the ratio of 10 and 20%. 5. Among 20, 30 and 50% extensions of water soluble phenol formaldehyde resin, wet shear strength of wood flour and bark powder was higher than that of wheat flour. Wet shear strength of wood flour in the ratio of 10% was shown the same tendency as above.

한지 슬러지 , 목재 파티클 복합보드의 제조연구 : 1 . 한지 슬러지 , 목재 파티클 복합보드의 물리적 성질 1 . Physical Properties of Hanji (Korean Paper) Sludge , Wood Particle Composite

이필우,손정일,이학래 한국목재공학회 2001 목재공학 Vol.29 No.2

This research was carried out to develop the Hanji(Korean paper) sludge·wood particle composite utilizing the waste sludges occurring from the making process of Hanji(Korean paper). In the research, four mixing ratios of white or black sludge to wood particle(10: 90, 20: 80, 30: 70, and 40: 60), three types of the resin adhesives(PMDI, urea and phenol resin) and three levels of the densities(0.60, 0.75 and 0.90) were designed to investigate the physical properties of Hanji(Korean paper) sludge ·wood particle composite. The linear expansion of Hanji(Korean paper) sludge·wood particle composite was not always increased, compared to control hoards. For thickness swelling, PMDI-bonded composites had the lowest value, and thickness swelling of composite was generally decreased with the increase of Hanji sludge. The water absorption of white sludge·wood particle composite had no tendency, but that of black sludge·wood particle composite was decreased with an increase of mixing ratio of Hanji sludge.