폐 MDF 폭쇄 섬유로부터의 MDF제조

이화형,서인수,조윤민,박한상,Lee Hwa-Hyoung,Seo In-Su,Cho Youn-Min,Park Han-Sang 한국가구학회 2005 한국가구학회지 Vol.16 No.1

This study was carried out to displace traditional virgin wood fiber by exploded MDF-waste fiber for the manufacture of medium density fiberboard. MDF waste was exploded in condition of $215^{\circ}C,20$ minutes. The higher the mixing ratio of exploded MDF-waste fiber, the lower the MOR and IB of MDF. There was no difference of formaldehyde emission by desiccator method between virgin wood fiber and exploded MDF-waste fiber. Adding $25^{\circ}C$ of exploded MDF-waste fiber met the KS of MDF 15 type.

폐MDF의 해리와 고해처리를 통한 고밀도 Fiber Board제조

이화형,서인수,조윤민,박한상,Lee, Hwa-Hyoung,Seo, In-Su,Cho, Youn-Min,Park, Han-Sang 한국가구학회 2006 한국가구학회지 Vol.17 No.1

This study was carried out to resplace traditional virgin wood fiber by recycled MDF-waste fiber for the manufacture of high density fiberboard. For the recycling, MDF waste was disintegrated for 10 minutes and beaten for 15 minutes. There was no difference in formaldehyde emission by desiccator method between virgin wood fiber and disintergrated and beaten MDF-waste fiber. Fiberboard which was maded from 100% of disintergrated and beaten MDF-waste fiber showed similar physical and mechanical properties to those of virgin fiber. The yield of recycled fiber from MDF waste was 85%.

아세칠화 WPC 이중개질처리에 의한 전통창호 소나무재의 물성 개선

이화형,이민경,Lee Hwa Hyoung,Lee Min Gyoung 한국가구학회 2003 한국가구학회지 Vol.14 No.1

Wood cell-wall modification with acetic anhydride, lumen filled with styren monomer and methyl methacrylate, and a combination of these two treatments were studied for their effectiveness for dimensional stability. Compared to those of untreated Pinus densiflora Sieb. et Zucc and sole acetylated red pine, The combination of acetylation and impregnation with methy methacrylate greatly reduced water absorption, increased ASE to the best and gave better bending strength and compression strength.

타닌 - MDI 접착제와 UF 의 혼합비에 따른 포름알데히드 방산 제거효과

이화형,강석구,김환생 ( Hwa Hyoung Lee,Seog Goo Kang,Hwan Saeng Kim ) 한국목재공학회 1995 한국목재공학회 학술발표논문집 Vol.1995 No.-

습식공법으로 제조한 목탄-목재섬유복합재료의 에틸렌가스 흡착력과 과일 신선도 유지 효과

이화형,김관의,Lee Hwa Hyoung,Kim Gwan Eui 한국가구학회 2003 한국가구학회지 Vol.14 No.1

This research was carried out for packing materials and building materials to examine thylene gas adsorption and effect of keeping fruit fresh of wet formed charcoal-fiber mposite made from defibrated fiber of Pinus densiflora Sieb. et Zucc. and white charcoal from uercus variabilis Bl.(wood fiber: charcoal=8:2, 6:4, 4:6, 2:8), with/without phenol formaldehyde resin(PF, Non volatile content:$52\%$, resin content $1,3,5\%$). The results are summarized as follows: 1. The higher the charcoal content, the more the ethylene gas adsorption. At the same mixing ratio of fiber to charcoal, $\#100-200$ of charcoal particle size gave the better reslts than $\#60-100$. 2. Adding PF into the charcoal fiber composite decreased the capacity of ethylene gas adsorption but there was no significant difference until $5\%$ adding amount of PF. 3. For keeping fruit fresh for a long time, Charcoal fiber composite was $66\%$ longer than control. The higher the white charcoal content, the longer fresh time.

오버레이 백탄보드의 에칠렌가스 흡착과 딸기 보관성 효과

이화형 ( Hwa Hyoung Lee ),조윤민 ( Youn Mean Cho ),박한상 ( Han Sang Park ) 한국목재공학회 2004 목재공학 Vol.32 No.5

한국산 주요 수종 (樹種) 수피의 (樹皮) 이학적 성질에 관한 연구 - 소나무속 , 사시나무속 , 참나무속을 중심으로 -

이화형 ( Hwa Hyoung Lee ) 한국산림과학회 1977 한국산림과학회지 Vol.33 No.1

A bark comprises about 10 to 20 percents of a typical log by volume, and is generally considered as an unwanted residue rather than a potentially valuable resourses. As the world has been confronted with decreasing forest resources, natural resources pressure dictate that a bark should be a raw material instead of a waste. The utilization of the largely wasted bark of genus Pinus, Quercus, and Populus grown in Korea can be enhanced by learning its physical and mechanical properties. However, the study of tree bark grown in Korea have never been undertaken. In the present paper, an investigative study is carried out on the bark of three genus, eleven species representing not only the major bark trees but major species currently grown in Korea. For each species 20 trees were selected, at Suweon and Kwang-neung areas, on the same basis of the diameter class at the proper harvesting age. One 200㎠ segment of bark was obtained from each tree at brest height. Physical properties of bark studied are: bark density, moisture content of green bark (inner-, outer-, and total-bark), fiber saturation point, hysteresis loop, shrinkage, water absorption, specific heat, heat of wetting, thermal conductivity, thermal diffusivity, heat of combustion, and differential thermal analysis. The mechanical properties are studied on bending and compression strength (radial, longitudinal, and tangential). The results may be summarized as follows: 1. The oven-dry specific gravities differ between wood and bark, further more even for a given bark sample, the difference is obersved between inner and outer bark. 2. The oven-dry specific gravity of bark is higher than that of wood. This fact is attributed to the anatomical structure whose characters are manifested by higher content of sieve fiber and sclereids. 3. Except Pinus koraiensis, the oven-dry specific gravity of inner bark is higher than that of outer bark, which results from higher shrinkage of inner bark. 4. The moisture content of bark increases with direct proportion to the composition ratio of sieve components and decreases with higher percent of sclerenchyma and periderm tissues. 5. The possibility of determining fiber saturation point is suggested by the measuring the heat of wetting. With the proposed method, the fiber saturation point of Pinus densiflora lies between 26 and 28%, that of Quercus accutissima ranges from 24 to 28%. These results need be further examined by other methods. 6. Contrary to the behavior of wood, the bark shrinkage is the highest in radial direction and the lowest in longitudinal direction. Quercus serrata and Q. variabilis do not fall in this category. 7. Bark shows the same specific heat as wood, but the heat of wetting of bark is higher than that of wood. In heat conductivity, bark is lower than wood. From the measures of oven-dry specific gravity (ρd) and moisture fraction specific gravity (ρm) is devised the following regression equation upon which heat conductivity can be calculated. The calculated heat conductivity of bark is between 0.8×10^(-4) and 1.6×10^(-4) cal/㎝-sec-deg. K=4.631 + 11.408ρd + 7.628ρm 8. The bark heat diffusivity varies from 8.03×10^(-4) to 4.46×10^(-4)㎠/sec. From differential thermal analysis, wood shows a higher thermogram than bark under ignition point, but the tendency is reversed above ignition point. 9. The modulus of rupture for static bending strength of bark is proportional to the density of bark which in turn gives the following regression equation. M=243.78X-12.02 The compressive strength of bark is the highest in radial direction, contrary to the behavior of wood, and the compressive strength of longitudinal direction follows the tangential one in decreasing order.

한국산 주요 수종 (樹種) 수피의 (樹皮) 화학적 성질 - (Ⅰ) 일반분석 , 환원당구성 , 무기원소 -

이화형 ( Hwa Hyoung Lee ) 한국산림과학회 1978 한국산림과학회지 Vol.40 No.1

A bark comprises about 10 to 20 percents of a typical log by volume, and is generally considered as an unwanted residue rather than a potential1y valuable resourses, As the world has been confronted with decreasing forest resources, natural resources pressure dictate that a bark should be a raw material instead of a waste. The utilization of the largely wasted bark of genus Pinus, Quercus, and Populus grown in Korea can be enhanced by learning their chemical properties. However, the chemical study of tree bark grown in korea have never been undertaken. In the present paper, the studies on the chemical properties of bark comprise carbohydrates, lignin, and extractives, composition of reducing sugars and five essential elements. The results may be summarized as follows: 1. Bark are much richer in quantity of lignin and extractives than the corresponding wood, and are chiefly consisted of lignin, extractives and carbohydrates orderly. It is the same with ash contents. Alcohol-benzene extractives of populus bark are the highest among three genus. 2. Although glucose constitutes the major sugar in both pine and hardwoods bark, in pinus, arabinose and xylose are the next but in hard woods, the next is xylose. 3. Essential elements, Ca and Kjeldahl-N are higher in the bark than in the wood. Ca content is the highest among others, and N,K followed it. Essential elements are higher in Quercus than in Populus and pinus.

합판용 고온경화형 (高溫硬化型) 수용성 요소 · 페놀공축합수지의 (共縮合樹脂) 성질과 그 접착강도

이화형 ( Hwa Hyoung Lee ) 한국산림과학회 1983 한국산림과학회지 Vol.60 No.1

Properties and glue shear strength of each water soluble rues-phenol copolymer adhesive and phenolic resin adhesive were examined as a high temperature curing binder through the manufacture of plywood made of Kapur veneer. The former has different molar ratio and the latter was made from different catalyst method. The results are summarized as follows: 1) Specific gravities of air dried plywood manufactured from each adhesive ranged from 0.67 to 0.82 and their moisture contents met the K.S, standard 2) In dry and wet shear strength, adhesives with 60 percent of non volatile content showed higher values than those with 50 percent except phenolic resin. Urea-phenol copolymer resin with 20 percent of phenol content exhibited the highest, and that with 70 percent the lowest. Filling effect of wood flour on the bonding strength is great in urea-phenol copolymer resin with more than 50 percent of phenol content, especially significant in 50 percent of non volatile content including alkali catalyst phenolic resin. Alkali and acid catalyst methods were the highest among the adhesive manufacture methods. In wet strenght, urea resin belongs to the lowest group. 3) In glue shear strength after boiling and drying test, no method for manufacturing phenolic formaldehyde resin adhesive was stronger than alkali and acid catalyst methods. Phenolic resin made from alkali catalyst method needs a wood flour filler to improve the bonding quality. Urea-phenol copolymer resin with 10 percent of phenol content showed the reasonable water resistance.

백탄파티클 크기와 최종매트함수율에 따른 백탄보드의 제조와 성능

이화형 ( Hwa Hyoung Lee ),조윤민 ( Youn Mean Cho ),박한상 ( Han Sang Park ) 한국목재공학회 2005 목재공학 Vol.33 No.3