Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
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Estimation of Radio Frequency Electric Field Strength for Dielectric Heating of Phenol-Resorcinol-Formaldehyde Resin Used for Manufacturing Glulam

구조용 집성재 제조용 접착제(Phenol-Resorcinol-Formaldehyde Resin) 유전 가열을 위한 고주파 전기장 세기 추산

  • Yang, Sang-Yun (Department of Forest Sciences, College of Agriculture and Life Sciences, Seoul National University) ;
  • Han, Yeonjung (Department of Forest Sciences, College of Agriculture and Life Sciences, Seoul National University) ;
  • Park, Yonggun (Department of Forest Sciences, College of Agriculture and Life Sciences, Seoul National University) ;
  • Eom, Chang-Deuk (Department of Forest Products, Korea Forest Research Institute) ;
  • Kim, Se-Jong (Department of Forest Products, Korea Forest Research Institute) ;
  • Kim, Kwang-Mo (Department of Forest Products, Korea Forest Research Institute) ;
  • Park, Moon-Jae (Department of Forest Products, Korea Forest Research Institute) ;
  • Yeo, Hwanmyeong (Department of Forest Sciences, College of Agriculture and Life Sciences, Seoul National University)
  • 양상윤 (서울대학교 농업생명과학대학 산림과학부) ;
  • 한연중 (서울대학교 농업생명과학대학 산림과학부) ;
  • 박용건 (서울대학교 농업생명과학대학 산림과학부) ;
  • 엄창득 (국립산림과학원 임산공학부) ;
  • 김세종 (국립산림과학원 임산공학부) ;
  • 김광모 (국립산림과학원 임산공학부) ;
  • 박문재 (국립산림과학원 임산공학부) ;
  • 여환명 (서울대학교 농업생명과학대학 산림과학부)
  • Received : 2014.02.27
  • Accepted : 2014.03.28
  • Published : 2014.05.25
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Abstract

For enhancing productivity of glulam, high frequency (HF) curing technique was researched in this study. Heat energy is generated by electromagnetic energy dissipation when HF wave is applied to a dielectric material. Because both lamina and adhesives have dielectric property, internal heat generation would be occurred when HF wave is applied to glulam. Most room temperature setting adhesives such as phenol-resorcinol-formaldehyde (PRF) resin, which is popularly used for manufacturing glulam, can be cured more quickly as temperature of adhesives increases. In this study, dielectric properties of larch wood and PRF adhesives were experimentally evaluated, and the mechanism of HF heating, which induced the fast curing of glue layer in glulam, was theoretically analyzed. Result of our experiments showed relative loss factor of PRF resin, which leads temperature increase, was higher than that of larch wood. Also, it showed density and specific heat of PRF, which are resistance factors of temperature increase, were higher than those of wood. It was expected that the heat generation in PRF resin by HF heating would occur greater than in larch wood, because the ratio of relative loss factor to density and specific heat of PRF resin was greater than that of larch wood. Through theoretical approach with the experimental results, the relative strengths of ISM band HF electric fields to achieve a target heating rate were estimated.

집성재의 생산성 향상을 위한 고주파 가열 경화기술에 대해 연구하였다. 고주파가 유전체에 가해지면 내부에서 에너지 손실에 의한 발열이 발생한다. 집성재를 구성하는 라미나와 접착제는 유전체이므로 집성재에 고주파를 주사하면 내부에서 발열이 발생한다. 집성재 제조에 이용되는 대부분의 상온 경화형 접착제는 고온에서 빠른 경화가 이루어지므로 고주파 가열 기술을 이용하면 집성재 내부 접착층의 온도를 상승시킴으로써 빠른 경화를 유도할 수 있다. 본 연구에서는 낙엽송재와 phenol-resorcinol-formaldehyde (PRF) 접착제의 유전 특성을 평가하고, 집성재 내부의 접착층의 빠른 경화를 유도하는 고주파 가열 경화 기작을 이론적으로 분석하였다. 연구 결과, 온도상승인자인 PRF 접착제의 상대손실계수가 낙엽송재의 상대손실계수에 비해 높았으나, 온도상승저해인자인 밀도와 비열도 높았다. 그러나 상대손실계수의 비율이 온도상승저해인자의 비율보다 높기 때문에 고주파 가열에 의한 발열량은 접착제에서 더 높을 것으로 예상된다. 이러한 실험 결과를 이용한 이론적 접근을 바탕으로, 접착층이 목표온도까지 상승하기 위한 ISM 영역의 고주파 주파수 별 전기장의 상대 세기를 추정하였다.

Keywords

References

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  1. Bonding Performance of Adhesives with Lamina in Structural Glulam Manufactured by High Frequency Heating System vol.43, pp.5, 2015, https://doi.org/10.5658/WOOD.2015.43.5.682