열처리 잣나무 정각재의 재색 변화 및 물성 조사

임호묵 ( Ho Mook Lim ),홍승현 ( Seung Hyun Hong ),강호양 ( Ho Yang Kang ) 한국목재공학회 2014 목재공학 Vol.42 No.1

국내의 주 생산 수종인 잣나무 90 × 90 mm 각재의 적정한 열처리 조건을 찾기 위해 3가지 열처리 스케줄을 적용하여 재색과 물성에 미치는 영향을 연구하였다. 1차 열처리 시 온도는 170°C와 190°C, 시간은 예비가열시간 1시간을 포함하여 9시간과 13시간을 적용하였다. 2차와 3차 열처리는 모든 공시 각재에 동일하게 190°C-9시간을 적용하였다. 열처리 횟수가 증가할수록 백색도 L*는 직선적으로 감소하였으며 표준편차도 감소하였다. 열처리 횟수가 증가할수록 색차 ΔE*는 직선적으로 증가하였으며, 표준편차가 커지는 경향이 있었다. 알려진 바와 달리 열처리 시편의 평균 종압축 강도가 무처리 시편보다 9% 높았다. 항팽윤율과 중량증가율을 측정하여 열처리 시편의 치수안정성이 무처리보다 크게 증가하였음을 보였다. Three heat-treatment schedules were applied to 90 × 90 mm dimension square lumber of Pinus koraiensis, one of major domestic species, and their colors and physical properties were investigated for obtaining an optimum schedule. Each square lumber was heat-treated three times. The temperatures of 170°C and 190°C, and the time of 9 hours and 13 hours were used for the first heat-treatment. The schedule of 190°C and 7 hours were used for the next two heat-treatments. The averages of brightness L* decreased linearly as the heat-treatment repeated and its standard deviations also decreased slightly. While the averages of color difference ΔE* increased linearly as the heat-treatment repeated and its standard deviations also increased slightly. The average compressive strength of the heat-treated specimen was higher than that of the control by 9%, which deviates from previous reports. ASE and WPG of the heat-treated specimens were measured to confirm that heat-treatment improved dimensional stability significantly.

국산 유용 수종의 오일열처리 연구 I

강춘원(Chun-Won Kang),임호묵(Ho-Mook Lim),강호양(Ho-Yang Kang) 한국가구학회 2015 한국가구학회지 Vol.26 No.2

Among several thermal wood modification methods German oil heating technology was applied for color changing larch and paulowniawood specimens. They were heat treated at 200°C for 3 hours in an autoclave filled with linseed oil. The CIE L*a*b* color indexes of the shells and cores of the oil heated specimens were measured. The color difference indexes between the oil heated and the control specimens of larch and paulowniawood were in the range of 6 and 12, which implies considerably different. The color difference indexes between the core layers of the larch and paulowniawood specimens were 4.3 and 1.7, respectively. It could be concluded that the specimens of the two species were color changed uniformly by oil heating.

180℃와 200℃ 오일열처리 잣나무재의 재색변화

이원희 ( Won-hee Lee ),임호묵 ( Ho-mook Lim ),강호양 ( Ho-yang Kang ) 한국목재공학회 2015 목재공학 Vol.43 No.4

유럽에서 개발된 여러 가지 열개질처리 방법 중 독일의 오일열처리 방법을 적용하여 국산 잣나무 시편을 180℃와 200℃에서 열처리하였다. 또 같은 종류의 잣나무 시편을 200℃에서 Thermowood열처리하였다. 열처리 시편의 표면을 자동대패로 대패한 후 1 mm와 4 mm 깊이의 재색을 색차계로 측정하였다. 열처리 시편 내층의 평균 백색도(L*)는 Oil-180 시편이 가장 높고, Oil-200 시편, Tmo-200 시편 순이다. 열처리에 의해 평균 적색도는 모든 시편이 증가하였으나 평균 황색도는 열처리 조건에 따라 증가하거나, 감소하였다. 무처리와 비교한 평균 색차값(△E*)은 Oil-200 시편과 Tmo-200 시편이 30.0 이상이나, Oil-180 시편은 18.4로 상대적으로 적게 변하였다. 열처리 시편 내층간의 평균 색차값(△E*)은 6.0 이하로 세 열처리 조건 모두 시편 내층의 재색을 균일하게 변화시켰다고 할 수 있다. Among several thermal wood modification methods German oil heating technology was applied to Korean pine specimens by heat treatment at 180℃ and 200℃. In addition the matched specimens were heat-treated by Thermowood method. The heat-treated specimens were planed and their colors were measured with a colorimeter at 1 mm and 4 mm below the surfaces. The average lightness index (L*) of Oil-180 specimens was the largest followed by Oil-200 and Tmo-200 specimens. The average redness indexes (a*) of all specimens were increased by heat treatment, while the average yellowness indexes (b*) were variable. The average color differences (△E*) of Oil-200 and Tmo-200 specimens were above 30.0, while that of Oil-180 specimens was only 18.4. It can be concluded that the colors of the heat-teated specimens were uniformly changed because their average color difference indexes (△E*) between the inner layers were below 6.0.

열처리에 의한 청변균 변색 소나무 판재의 재색 변화

이원희(Won-Hee Lee),임호묵(Ho-Mook Lim),강호양(Ho-Yang Kang) 한국가구학회 2014 한국가구학회지 Vol.25 No.4

Red pine is a popular species for making a cutting board in Korea, but easily sap stained. Heat treatment could improve its quality by darkening and equalizing the color of sap stained wood. The color change of sap stained red pine boards was investigated by heat treatment at 190℃. It was observed that the color of heat treated boards got darker and it made the color of sap stain vanished. A colorimeter was used to measure color indexes. It was revealed that the values of the lightness (L*) and the yellowness (b*) decreased as heat treatment repeated while the values of the redness (a*) increased. The average of the color difference (△E*) between the control and 1st heat treated boards was 16.1, which could be expressed as ‘Extremely different’ while that between the 1st and 2nd heat treated boards was 8.3, which could be expressed as ‘Considerably different’. The fact that heat treatment equalized the color of boards was confirmed by a statistical analysis.

휴대용 유전율식 수분계를 이용한 목재의 전건밀도 추정

강춘원 ( Chun-won Kang ),임호묵 ( Ho-mook Lim ),강호양 ( Ho-yang Kang ) 한국목재공학회 2017 목재공학 Vol.45 No.5

현재 합천 해인사에 보관되어 있는 고려속장경(일명 팔만대장경)은 역사적 가치나 규모면에 있어서 세계적인 문화재이나 아직도 어떤 수종으로 만들어졌는지 모르고 있다. 중요한 문화재이기 때문에 손상없이 비파괴적으로 수종을 추정하는 방법이 필요하다. 밀도를 알게 되면 수종을 추정하기 쉽다. 유전율식 목재수분계의 원리를 역으로 이용하면 함수율을 알고 있는 목재의 전건밀도를 얻을 수 있다는데 착안하여 연구를 수행하였다. 국내산 100여 개 수종, 122개 재감의 전건밀도를 치수법과 유전율식 목재수분계 추정법으로 구하여 두 계수의 상관관계와 회귀식을 찾았으며 문헌자료를 이용하여 회귀식의 유의성을 검정하였다. 치수법으로 측정한 전건밀도와 유전율식 목재수분계로 추정한 전건밀도는 매우 높은 상관관계를 나타냈다. 이 관계식을 이용하면 팔만대장경판의 전건밀도를 추정할 수 있으며 나아가 수종을 예측할 수 있을 것이다. Tripitaka Koreana in Haein Temple, Hapcheon Province is the most historical and largest heritage in this country, however the species of their blocks have yet been unknown. A nondestructive test method is necessary to investigate their species. The oven-dry density of wood was measured by inversely using the principle of high frequency moisture meter. The oven-dry densities of more than 100 domestic species of specimens estimated by measurement method and high frequency moisture meter were compared and following conclusions were obtained. There was highly close correlation between the oven-dry density estimated by measurement method and the oven-dry density estimated by high frequency moisture meter. The densities of Tripitaka Koreana that was a global cultural heritage could be correctly estimated by using high frequency moisture meter and the equilibrium moisture content under which Tripitaka Koreana equilibrated, thus, it was expected to provide the key to species identification.

PEG 주입 침엽수 시편의 열처리 후 PEG 잔류량과 평형함수율 측정

홍승현 ( Seung Hyun Hong ),김정호 ( Chung Ho Kim ),임호묵 ( Ho Mook Lim ),강호양 ( Ho Yang Kang ) 한국목재공학회 2013 목재공학 Vol.41 No.3

PEG 주입을 통해 열처리 중 목재의 균열을 방지하기 위한 연구에 필요한 기초자료를 제공하기 위해 본 연구가 수행되었다. 국내에서 사용되는 대표적인 침엽수 세 수종의 소시편을 이용하여 PEG 분자량에 따른 침투 속도와 잔류량, 열처리 후 잔류량, 평형함수율 등을 조사하였다. PEG400의 평균 잔류량은 수종별 기본밀도에 반비례하였으며 다른 분자량 PEG에서도 비슷한 경향을 나타냈다. 한 수종 내에서는 PEG 분자량이 클수록 잔류 PEG 양이 감소하는 경향이 뚜렷하다. PEG 주입에 의해 함수율이 2% 내에서 증가하거나 감소하였으며, 시편의 평균 기본밀도는 최고 16.8%까지 증가하였다. 열처리에 의한 중량감소율은 PEG400 시편이 PEG600, PEG1000 보다 컸다. 낮은 분자량의 PEG가 더 많이 용출되었다고 볼 수 있다. 평형함수율은 상대습도가 낮을 때 (32%RH) 세 수종 모두 PEG 주입 시편과 무처리 시편의 차이가 없었으나, 상대습도가 증가할수록 PEG 주입 시편이 무처리 시편보다 높게 나타났다. This study was carried to provide basic data for the research of the effect of PEG impregnation on preventing wood from cracking during heat treatment. Three popular softwood species were selected for investigating the PEG penetration rate and retention depending on PEG molecular weight, PEG retention after heat treatment and their EMCs. The average retentions of PEG400 were reversely proportional to the basic densities of three species and those of the other PEGs showed similar behaviour as well. It is obvious that PEG retention decreased as PEG molecular weight increased with a species. PEG impregnation increased or decreased the moisture contents of the specimens within 2%, and increased their basic densities by ]6.8% as a maximum. The Weight Percentage Losses of PEG400 during heat treatment were the largest among three PEG levels, which implied that lower molecular weight PEG leached more than the highers, There was less difference in EMC between PEG impregnated and control specimens at low RH, bur their difference increased at high RH.