• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.243-249
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• 2017

This study was performed to find out the optimum adhesive conditions on manufacturing a cross-laminated timber (hereinafter CLT) with using domestic Korean Pine (Pinus koraiensis). The adhesive conditions including a applied amount of the glue and a Pressure are the one of the most important key factors on establishing CLT production process. The shear strength was examined with differing the adhesive conditions while using Phenol Resorcinol Formaldehyde Resin Adhesive (PRF resin). The optimum adhesive conditions was confirmed to be: glue spread of $250g/m^2$ and Pressure of 0.8 MPa respectively. The grain directions of glued specimens were also considered, perpendicularly bonded and parallelly bonded groups. Shear strength of the former group showed lower values than the latter group which is considered to be the effect of a rolling shear. Meanwhile the shear strength of both group satisfied the Korean Standard (KS F 3021) and the European Standard (EN 14080 and EN 16351). The results derived from this study can be used as the basic data for manufacturing the CLT with domestic Korean Pine. And additional researches for the other species including domestic Korean Larch and Pitch Pine is also now being performed.

• Journal of the Korean Electrochemical Society
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• v.2 no.3
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• pp.134-137
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• 1999

The polyacenic semiconductor material (PAS) electrode prepared by the pyrolytic treatment of phenol-formaldehyde resin is one of useful electrodes. As an anode material of lithium rechargeable batteries, amorphous carbon materials have been studied extensively because of their high electrochemcal performance and cyclicability. Carbon materials do not lead to the formation of lithium dendrite which is one of the most serious problems in applying Li-based materials to an electrode of batteries. The polyacene materials prepared from phenol resin at relatively low temperatures $(550\~750^{\circ}C)$ show a highly Li\doped state up to $C_2Li$ state without liberation of Li cluster. We prepared each polyacene materials at various temperature and investigated electro- chemical properties. We tried to change the mole ratio of [H]/[C] which is $0.24\~0.4$ range. Considering of electrochemical properties of PAS material, the PAS material is one of the most suitable materials for electrodes of a polymer battery.

• Journal of the Korean Wood Science and Technology
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• v.39 no.3
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• pp.221-229
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• 2011

Due to the increase of oil price and the environmental issue such as the emission of volatile organic compounds, the necessity for developing alternative resins of petroleum-based adhesive resins, which have extensively been used for the manufacture of wood-based products, has been speculation since the early 1990. In our study, rapeseed flour (RSF), which is the by-product of bio-diesel produced from rapeseed, were hydrolyzed by enzymes. As a crosslinking agents of the RSF hydrolyzates, phenol-formaldehyde prepolymers (PF) were prepared. The RSF hydrolyzates and PF were mixed to complete the formulation of RSF-based adhesive resins, and the resins were applied to make the laminated veneer lumber (LVL). The physical and mechanical properties of the LVL were measured to examine whether RSF can be used as raw materials of adhesive resins for the fabrication of LVL or not. The average moisture content and soaking delamination rate of the LVL bonded with RSF-based adhesive resins exceeded the minimum requirement of KS standard. Moreover, thermal analysis of the RSF-based resins showed similar tendencies except for the RSF-based adhesive resins formulated with pectinase-hydrolyzed RSF. The bending strengths of the LVL were higher than that of the LVL made with commercial PF resins. These results showed the potential of RSF as a raw material of alternative adhesives for the production of LVL. Further works on the optimal conditions of RSF hydrolysis and spreading characteristics for RSF-based adhesive resins is required to improve the adhesive performance of RSF-based resins.

• Journal of Korean Society of Forest Science
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• v.60 no.1
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• pp.51-57
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• 1983

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 strength, 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.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.599-612
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• 2017

Human hair (HH) is produced as a waste from beauty parlor and barbershop. HH-based adhesives were formulated with NaOH-hydrolyzed HH, $H_2SO_4$-hydrolyzed chicken blood (CB) and PF as a crosslinking agent. Physicochemical properties and retention rate against hot water of the adhesives were measured to investigate the potential of HH as a raw material of wood adhesives. HH was composed of keratin-type protein of 80% and over. Ash of less than 0.1% was contained in HH. Among the amino acids included in HH, glutamic acid showed the highest content, followed by cysteine, serine, arginine and threonine. Solid content of the adhesives ranged from 33.2% to 41.8% depending on hydrolysis conditions of HH and PF type. Viscosity at $25^{\circ}C$ ranged from 300 to $600mPa{\cdot}s$ resulting in a sprayable adhesive. Retention rate against hot water measured to evaluate the water resistance of adhesives was the highest in the cured resin formulated with 5% NaOH-hydrolyzed HH and 5% $H_2SO_4$-hydrolyzed CB. Meanwhile, the molar ratio of formaldehyde to phenol in PF did not have a significant impact on the retention rate of HH-based adhesives. When the retention rates of HH-based adhesives were compared to those of conventional wood adhesive resins used for the production of wood-based panels extensively, HH-based adhesives formulated with 30 wt% PF showed lower retention rate than commercial urea-formaldehyde resin. However, when PF content was increased to 35 wt%, the retention rate greatly increased and approached to that of commercial melamine-urea-formaldehyde resin. Except for the results mentioned above, the analysis of economic feasibility suggests that HH-based adhesives can be used for the production of wood-based panels if HH is hydrolyzed in proper conditions and then the HH-based adhesives are formulated by the HH hydrolyzates with 35 wt% PF.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.171-176
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• 2013

The need of volatile organic compound (VOC) free coating material has been increased to solve environmental problems such as the global warming. Nowadays, about 70~80% of coating materials used in the worldwide are a liquid type. Therefore, the development of non-solvent coating material that can minimize VOCs emissions is necessary to solve the global warming problem. In this study, acrylic monomers were added to develop non-solvent paints in order to improve disadvantages of the poor adhesion of a conventional phenolic resin caused by acidification. As a result, the blend resins of 2.818 Mpa phenol- formaldehyde resin/poly methyl methacrylate (PE/PMMA) has the best properties and performances for the adhesives.

• Journal of agriculture & life science
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• v.46 no.2
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• pp.43-48
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• 2012

This study was investigated on the properties of board made from Miscanthus sinensis var. purpurascens particles differed in density of board and mixed ratio of powder type- and liquid type-phenolic resin. As the board density increase, thickness swelling and bending strength increased while water absorption decreased. With increasing the resin content, water absorption and thickness swelling decreased while MOR and internal bond strength increased. The board made of liquid type phenol-formaldehyde resin was low in water absorption and thickness swelling, and there were similar bending strengths between power type- and liquid type-phenol resin in resin cont of 11% and 13% at the board density $0.4g/cm^3$ and internal bond strength was higher with liquid type-phenolic resin in its bending strength.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.528-537
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• 2015

To reuse the waste bone from restaurants or butcher houses, the possibility of using waste bone powder after cooking as a filler for wood adhesives used in manufacturing plywood was investigated. Radiata pine (Pinus radiata D. Don) plywoods were manufactured by using commonly used wood adhesives such as urea-melamine formaldehyde (UMF) resin, urea-formaldehyde (UF) resin, and phenol-formaldehyde (PF) resin and the prepared fillers from cattle bone powder, pig bone powder, and seashell powder. Plywood fabricated by using cattle bone powder, pig bone powder, and seashell powder showed weaker performance in dry and wet glue-joint shear strength and wood failure than those of the plywood with wheat flour. The result showed that it was hard to use only bone powder for the replacement of wheat flour. However, the filler mixed with wheat flour and bone powders showed equivalent dry bonding strength and better water resistance than the wheat flour, indicating that bone powders mixed with wheat flour might be used for the manufacture of plywood. When bone powders were mixed with wheat flour as adhesive fillers the shell powder showed the lowest bonding properties and there was no big difference between the cattle bone powder and the pig bone powder.

• Journal of the Korean Wood Science and Technology
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• v.33 no.3 s.131
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• pp.38-44
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• 2005

This research investigated the variation of density, the weight loss, dimensional shrinkage and heat conduction by the heating rate and keeping time at maximum temperature of woodceramics, when sawdust boards made from thinned logs of Pinus densiflora, Larix kaemferi and Pinus koraiensis were impregnated with phenol-formaldehyde resin, and then were formed by heating rate ($2^{\circ}C/min{\sim}6^{\circ}C/min$) and keeping time at maximum temperature (1~5 h). As the heating rate increased, the density and thickness shrinkage decreased, but weight loss and linear shrinkage increased. The more the keeping time at maximum temperature, the greater the linear shrinkage and thickness shrinkage. The heating conduction was superior at the heating rate is $2^{\circ}C/min$ and the keeping time at maximum temperature of 2 hs.

• Journal of the Korean Wood Science and Technology
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• v.33 no.5 s.133
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• pp.66-75
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• 2005

Soybean-based adhesives have recently been reconsidered as alternatives to petroleum-based adhesives due to the uncertainty of availability of petrochemical products and the increased demand for wood adhesives. This study was conducted to investigate the adhesive properties of alkaline phenolic soy (APS) resin for hybrid poplar flakeboard. The APS resin was formulated by crosslinking an alkaline soy flour hydrolyzate with lab-prepared PF resin in the soy hydrolyzate to PF resin weight ratios of 70/30, 60/40, and 50/50. The APS resins were used to fabricate homogeneous hybrid poplar flakeboards with different resin solid levels (5%, 7%, and 9%), press temperatures (175 and $200^{\circ}C$), and press times of 8 and 10 minutes. The IB, wet MOR, and dimensional stability properties of board improved with increasing press time, press temperature, and PF level in APS resins. Increasing press time can be used to offset poor IB strength associated with a 9% resin solid level and the excessive moisture content in the mat. The following conditions were concluded to meet the requirements of the CSA standard for exterior-grade flakeboard: a 50% PF level, a 5% resin content, a $200^{\circ}C$ press temperature, and an 8 minute press time.