• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.41 no.1
• /
• pp.44-51
• /
• 2009

Proper test methods and instruments for evaluating score or creasing crack have not been provided, although score crack trouble occurs frequently in manufacturing corrugated containers. Because existing creasability tester has the limitation of the available thickness of test piece and folding rate, it cannot be used for corrugated fiberboards with high thickness. In this study, we developed the laboratory test instrument and the method to determine the score or creasing crack of corrugated fiberboard. This instrument can evaluate folding resistance of corrugated board without restriction on the folding rate and thickness of specimen. Corrugated fiberboard had the different folding behavior from linerboard when it was creased. By using this test machine, score crack can be objectively determined by folding test piece to the certain folding angle with constant folding rate.

• Journal of the Korean Wood Science and Technology
• /
• v.19 no.3
• /
• pp.27-34
• /
• 1991

Screw withdrawal test was carried out on the face and edge of domestic particleboard and medium density fiberboard in order to evaluate optimum pilot hole diameter. The obtained results were as follows: 1. Maximum withdrawal strengths on the face and edge of particleboard were obtained with pilot hole diameters at about 50% of root diameters of screw. 2. Maximum withdrawal strength on the face and edge of medium density fiberboard were obtained with pilot hole diameters that were about 60% and 50% of root diameters of screw, respectively. 3. Withdrawal strength showed about 91% of maximum withdrawal strength when pilot holes were not pre bored at particleboard. but when pilot holes at 90% of root diameter of screw withdrawal strength showed about as 51.3% of maximum withdrawal strength. 4. Withdrawal strength showed about 88% of maximum strength when pilot holes were not used, but withdrawal strength indicated 55.4% of maximum strength in case of 90% of root diameters of screw. 5. Maximum withdrawal strength on the face of particleboard was about 70.5% higher than that of the edge, and however medium density fiberboard was about 19.6% higher than that of the edge.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.39 no.2 s.120
• /
• pp.38-44
• /
• 2007

The hygroscopic property of paper is important for convertability and end use performance. When the board and corrugated fiberboard are exposed to low relative humidity, a trouble of score (or crease) cracking could occur. In this study, we evaluated the moisture content and mechanical properties of linerboard and corrugated board at the cyclic condition of low humidity to prevent a score crack trouble. As the relative humidity decreased from 50% to 38% and 25%, the moisture content of linerboard decreased about 7% to 6% and 4%. At low humidity, most of mechanical properties were improved except for strain. The linerboard exposed at 25% RH showed a remarkable reduction of strain by 11%. At the same relative humidity, linerboard and corrugated fiberboard showed the different property values depending on moisture hysteresis.

• Applied Chemistry for Engineering
• /
• v.24 no.6
• /
• pp.672-675
• /
• 2013

Fast pyrolysis of medium-density fiberboard was carried out using a fluidized-bed reactor under various conditions to find an optimum pyrolysis condition. When the pyrolysis temperature was varied between $425^{\circ}C$ and $575^{\circ}C$, the maximum bio-oil yield of 52 wt% was obtained at $525^{\circ}C$. The quality of the bio-oil product increased with increasing pyrolysis temperature. Pyrolysis at a high temperature removed significant amounts of oxygenates and acids, producing more valuable species such as aromatics and phenolics. The main gaseous products were CO and $CO_2$. The yields of CO and $C_1-C_4$ hydrocarbons increased with increasing the pyrolysis temperature.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.27 no.2
• /
• pp.91-100
• /
• 2021

Agricultural corrugated fiberboard packaging boxes frequently experience damage due to loading and unloading, vibration during transport, and shock by dynamic distribution condition change. This study was carried out to estimate effect of vibration during distribution process on compression strength of corrugated fiberboard boxes for agricultural products. In order to identify the degradation caused by vibration, after box packaging the agricultural products(tangerine or cucumber), the natural frequencies of the packaging boxes were measured by varying the relative humidity(50, 70 and 90%) at 25℃ temperature. Various types of corrugated fiberboard boxes were packed with tangerines and cucumbers, and the PSD plot vibration tests were conducted by utilizing the actual vibration recording results of the Gyeongbu Expressway section between Seoul and Gimcheon. As a result of the experiment, the decrease in compression strength of the box was relatively low in DW-AB, and the decrease in compression strength of the SW-A 0201(RSC) type box was the highest at 20.49%. In particular, both SW-A and DW-AB showed low compression strength degradation rates for open folder type boxes. The moisture content varies depending on the type of the box or agricultural products, and the enclosed 0201(RSC) type box was generally higher than the open folder or bliss type box, which is believed to be the reason for the decrease in compression strength of RSC type box due to humidity. By the agricultural product, the percentage of decrease in compression strength of box packed with cucumbers was especially high.

• Journal of the Korean Wood Science and Technology
• /
• v.42 no.5
• /
• pp.597-604
• /
• 2014

Laboratory-scale landfills (simulated landfills) were designed to determine the formaldehyde released into air and leachate from medium density fiberboard (MDF). Simulated landfills were constructed using cylindrical plastic containers containing alternating layers of soil and MDF for a total of five layers. The highest concentration of formaldehyde was found in the air and leachate from the MDF only treatment compared to treatments containing MDF and soil. At the end of the study (28 days), formaldehyde concentrations in air and leachate from treatments containing MDF and soil decreased by 70 percent and 99 percent, respectively, while the treatment containing MDF only still released formaldehyde into the air and leachate. Therefore, waste MDF after storing 4 weeks in water may be recycled as compost or mulch based on formaldehyde leaching. Also, these data indicate soil restricts formaldehyde release into air and leachate and provides new information about the fate of wood-based composite waste containing UF resin disposed in landfills.

• Journal of Biosystems Engineering
• /
• v.21 no.2
• /
• pp.191-197
• /
• 1996

Allowable stacking duration of the corrugated fiberboard boxes being widely used for packaging fruits and vegetables was analyzed by the creep behavior and the cumulative load correction factor for the boxes. The stacking boxes were assumed to be stored at a nearly constant temperature and relative humidity condition. When the stacking duration was short period, the stacking height determined by two methods showed a little difference between them, but almost no difference was shown as the stacking duration was longer. Allowable stacking duration was rapidly decreased with the increase of static load applied on the stacking boxes, and allowable stacking duration of Box A was estimated the longer than that of Box B. A model of allowable stacking duration for the corrugated fiberboard box was developed as a function of the stacking load and the ambient relative humidity.

• Journal of the Korea Furniture Society
• /
• v.17 no.1
• /
• pp.63-71
• /
• 2006

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%.

• International Journal of Reliability and Applications
• /
• v.4 no.4
• /
• pp.157-170
• /
• 2003

In this paper we apply statistical reliability tools to manage and seek improvements in the strengths of medium density fiberboard (MDF). As a part of the MDF manufacturing process, the product undergoes destructive testing at various intervals to determine compliance with customer′s specifications. Workers perform these tests over sampled cross sections of the MDF panel to measure the internal bond (IB) in pounds per square inches until failure. We explore both graphically and statistically this "pressure-to-failure" of MDF. Also, we briefly comment on reducing sources of variability in the IB of MDF.

• Journal of the Korean Wood Science and Technology
• /
• v.49 no.5
• /
• pp.453-461
• /
• 2021

In wood-based composite panels, low-molar ratio (LMR) urea-formaldehyde (UF) resins usually result in reduced formaldehyde emission (FE) at the expense of poor adhesion. However, the FE and adhesion of medium-density fiberboard (MDF) bonded with LMR UF resins were both improved in this study. The modified LMR UF resins with transition metal ion-modified bentonite (TMI-BNT) nanoclay simultaneously improved the FE and adhesion of MDF panels. The modified LMR UF resins with 5% TMI-BNT resulted in a 37.1% FE reduction and 102.6% increase in the internal bonding (IB) strength of MDF panels. Furthermore, thickness swelling and water absorption also significantly decreased to 13.0% and 24.9%, respectively. These results imply that TMI-BNT modification of LMR UF resins could enhance the formation of a three-dimensional network rather than crystalline domains, resulting in improved cohesion.