• 한국의류학회지
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• 제10권2호
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• pp.59-67
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• 1986

To control the amounts of formaldehyde released from the cotton fabric finished with N-methylol compounds, glycerol was used as a formaldehyde-scavenging agent. It was observed the effects of catalysts and curing conditions when aftertreated with glycerol on melamine resin finished fabric. The effects of Different processes of glycerol treatment, and different resins, urea resin and melamine resin, were compared. The conclusions obtained from the results are as follows: 1) It was shown hatt the aftertreatment with glycerol (treated without catalyst) was more effective than treated with catalysts in controlling free formaldehyde. 2) The optimum curing temperature and curing time for the glycerol aftertreatment without adversely affecting the other properties of fabric was about $160^{\circ}C$, 3 min. 3) According to the increase of glycerol concentration in both aftertreatment and simultaneous treatment the amounts of free formaldehyde was reduced. The rate of decrease was manifest within the limits of $6\%$ in the case of simultaneous treatment with glycerol ana resins, and $3\%$ in the case of glycerol aftertreatment on resin finished fabrics. 4) Dry wrinkle recovery angle was decreased the increase of glycerol concentration. Melamine resin had a little adverse effect than urea resin, particulary glycerol aftertreatment. 5) The breaking strength was increased with the increase of glycerol concentration.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.672-681
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• 2015

As a part of abating the formaldehyde emission of amino resin-bonded wood-based composite panels, this study was conducted to investigate hydrolytic stability of urea-melamine-formaldehyde (UMF) resin depending on various hydrolysis conditions and hardener types. Commercial UMF resin was cured and ground into a powdered form, and then hydrolyzed with hydrochloric acid. After the acid hydrolysis, the concentration of liberated formaldehyde in the hydrolyzed solution and mass loss of the cured UMF resins were determined to compare their hydrolytic stability. The hydrolysis of cured UMF resin increased with an increase in the acid concentration, time, and temperature and with a decrease in the smaller particle size. An optimum hydrolysis condition for the cured UMF resins was determined as $50^{\circ}C$, 90 minutes, 1.0 M hydrochloric acid and $250{\mu}m$ particle size. Hydrolysis of the UMF resin cured with different hardener types showed different degrees of the hydrolytic stability of cured UMF resins with a descending order of aluminum sulfate, ammonium chloride, and ammonium sulfate. The hydrolytic stability also decreased as the addition level of ammonium chloride increased. These results indicated that hardener types and level also had an impact on the hydrolytic stability of cured UMF resins.

• 한국토양비료학회지
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• 제24권1호
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• pp.50-54
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• 1991

조입성형제(造粒成型劑)로 사용(使用)된 요소수지(尿素樹脂)의 U/F반응(反應) mole비(比) 및 첨가량(添加量)이 각각(各各) 다른 시제품(試製品) 5종(種)을 단비분시(單肥分施)를 대조(對照)로 배추에 대(對)한 비효시험(肥效試驗)을 실시(實施)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 배추수량(收量)은 U/F반응(反應) mole비(比) 1.0인 요소수지(尿素樹脂)가 6.7% 첨가(添加)된 시제품(試製品) V에서 가장 높았고 U/F반응(反應) mole비(比)가 가장 낮고 첨가량(添加量)이 가장 많은 시제품(試製品) VII에서는 3요소(要素) 분시구(分施區)에 비(比)하여 감수(減收)하였다. 2. 배추용(用) 완효성(緩效性) 복비(複肥)의 질소(窒素) 완효도(緩效度)는 24시간후(時間後) 수중전질소(水中全窒素) 용출률(溶出率) 76.1%, 100일후(日後) 토양중(土壤中) 전질소(全窒素) 용출률(溶出率) 71.7%가 적합(適合)하였다.

• Journal of the Korean Wood Science and Technology
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• 제51권1호
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• pp.14-22
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• 2023

Economical use of larix (larch) boards (grade 3) in industries is lower than that of imported hardwood; thus, studies have been conducted toward performance improvement of larix boards. Herein, flexural modulus of larix board samples laminated with wood adhesives polyurethane resins, poly (vinyl acetate) resins, phenol-resorcinol-formaldehyde resins, melamine-formaldehyde resins, and urea-formaldehyde resins was compared with that of the samples bonded with adhesives reinforced with mesh-type basalt fibers. Moreover, the flexural moduli of the laminated samples bonded by mesh-type basalt fibers were compared with those of reinforced samples. The results showed that boards laminated with polyurethane and urea-formaldehyde resin adhesives had higher flexural modulus than those without the lamination. In particular, the increase in the flexural modulus was relatively significant for the 2- and 3-ply board structures laminated with polyurethane adhesives compared to those with reinforcement. The 3-ply board structure without reinforcement had the highest flexural modulus when the urea-formaldehyde resin adhesive was used.

• Journal of the Korean Wood Science and Technology
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• 제16권1호
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• pp.3-8
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• 1988

This study was carried out to examine the effect of pretreatment of veneer with aluminum sulfate solution for the manufacture of the kapur plywood on the reduction of urea resin spread. The results were as follows: 1. Specific gravities of plywoods made of the kapur veneers ranged from 0.83 to 0.84 and their moisture contents based on air dry weight showed from 10.6% to 11.4%. These met the Korean Industrial Standards. 2. In the case of dry shear strength for the 3rd class plywood, 40% reduction- spread met K S as well as normal urea resin spread. pH of the aluminum sulfate solution gave better result at pH 4.5 and pH 6 than at pH 3. For the manufacture of the 2nd class plywood, hot and cold water-wet shear strength show the best results at the following conditions; such as 20% reduction spread, pH 4.5 of aluminum sulfate solution and all veneer treatment.

• Journal of the Korean Wood Science and Technology
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• 제47권2호
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• pp.221-228
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• 2019

This study reports the performance of urea-formaldehyde (UF) resins prepared at two different low formaldehyde/urea (F/U) mole ratios with different numbers of urea addition during synthesis. The second or third urea was added during the synthesis of UF resins to obtain two different low molar ratios of 0.7 and 1.0, respectively. The molecular weights, cure kinetics, and adhesion performance of these resins were characterized by the gel permeation chromatography, differential scanning calorimetry, and tensile shear strength of plywood, respectively. When the number of urea additions and F/U molar ratio increased, the gelation time decreased, whereas the viscosity and molecular weight increased. Further, the UF resins prepared with the second urea and 1.0 molar ratio resulted in greater activation energy than those with third urea and 0.7 molar ratio. Tensile shear strength and formaldehyde emission (FE) of the plywood that bonded with these resins increased when the number of urea additions and molar ratio increased. These results suggest that the UF resins prepared with 0.7 molar ratio and third urea addition provide lower adhesion performance and FE than those resins with 1.0 mole ratio and the second urea addition.

• Journal of the Korean Wood Science and Technology
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• 제16권3호
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• pp.17-21
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• 1988

In order to investigate the extending effects on urea-formaldehyde resin- or phenol- formal- dehyde resin- glued keruing plywood, hot pressing temperatures were controlled to 110, 140, 170 and $200^{\circ}C$. As the extender, wheat flour, persimmon bark powder, chestnut bark powder, the equivalently- extended with the above three powders, and diatomite powder were respectively mixed with 5, 10, 15 and 20% ratios to the resin liquid, and also with these the no- extended was allowed. Based on the measured bonding strength, the conclusions were drawn: 1. In the urea- formaldehyde resin, extending effects on the bonding strength were in the order of wheat flour, the equivalently- extended with the wheat flour, persimmon- and chestnut bark powder, persimmon bark powder, chestnut bark powder. In the phenol- formaldehyde resin, the effects in the order of wheat flour, persimmon bark powder, diatomite powder, chestnut bark powder were resulted in. Specifically, superior bonding strength to the no-extended were given with the wheat flour and persimmon bark powder. 2. On the whole, the bonding strength decreased gradually, as the hot pressing temperature increased except for the diatomite powder extending.

• 한국잠사곤충학회지
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• 제27권2호
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• pp.47-53
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• 1985

요소-formaldehyde 수지를 여러 가지 조건에서 견직물에 처리하여 다음과 같은 결과를 얻었다. 1. 수명수지의 생성 조건은 요소 1mol에 대하여 formaline을 2mod 이상 사용하여 pH 4∼5로 수지욕을 만들어야 한다. 2. 수지농도가 증가하는데 비례적으로 수지부착율도 증가한다. 상대적으로 수분율을 감소하는 경향을 보였다. 3. wet pick 70%, 80%, 90%, 100% 중에서 70%일 경우가 수지잔존율이 가장 높았다. 4. curing 조건에 따른 수지의 부착율은 온도가 높을수록 탈락율은 감소하며 부착율은 증가된다. 5. 촉매의 양은 (NH4)2SO4 경우는 수지에 대하여 2.5%, HCI 경우는 1%, tataric acid 경우는 10%가 적당하였고 나머지 NaHCO3, Zn(NO3)2·6H2O인 경우는 분석이 곤란하였다. 6. 촉매의 종류에 따른 부착율은 산성 혹은 (NH4)2SO4와 같은 잠복성 촉매가 뛰어난 효과를 나타냈다. 7. 촉매에 따른 세탁견뢰성은 산성 촉매일수록 뛰어난 효과를 나타냈다.

• 한국산림과학회지
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• 제94권6호
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• pp.476-480
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• 2005

벼와 보리 등의 농작물 짚은 파티클보드의 원료로서 부분적으로 대체 첨가 사용할 수 있었다. 파티클보드 접착용 요소-멜라민수지 접착제를 실험실에서 수지 접착제 고형분량에 대해 5% 멜라민을 첨가하여 합성하였다. 두개의 농작물 짚을 전건 목재파티클 무게에 대해 10, 20, 30, 40% 대체하여 혼합하고 합성한 요소-멜라민수지 접착제로 파티클보드를 제조하였다. 제조된 파티클보드는 물리적, 기계적 성능과 치수안정화에 대해 성능을 비교하였다. 성능평가 결과는 파티클보드에 볏짚과 보릿짚의 대체 첨가율이 증가됨에 따라 제조한 파티클보드의 성능은 감소하는 경향을 보여줬다. 전체적으로 농작물 짚은 파티클보드 제조의 원료로서 15% 대체하여 사용할 수 있었다.

• 한국가구학회지
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• 제18권1호
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• pp.20-30
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• 2007

This experiment was carried out to investigate the effects of number and location of finger joints on the bending strength of glue-laminated lumbers. Urea resin adhesives were used in this experiment and the resin content was 70% for cold pressing. The lamina were edge-jointed and end-jointed. The specimen were composed of one or three layers. The obtained results are summarized as follows; The effects of finger joints on the decrease of bending strength of glue laminated woods were different according to the number and location of finger joints. The decrease of MOR was highest on the middle position of laminated woods. The effects of several arrangements of finger joints on the bending strength of glue laminated woods showed on Figure 7 and 8. The variance of thickness-laminating on the bending strength of glue laminated woods were larger than those of width-laminating.