Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
권호 표지

Development and Application of Okara-based Adhesives for Plywood Panels

두부비지를 이용한 합판용 접착제의 개발 및 적용

  • Oh, Sei-Chang (Division Life & Environmental Resources, Deagu University) ;
  • Ahn, Sye-Hee (Division Life & Environmental Resources, Deagu University) ;
  • Choi, In-Gyu (Department of Forest Sciences, College of Agriculture and Life Sciences, Seoul National University) ;
  • Jeong, Han-Seob (Department of Forest Sciences, College of Agriculture and Life Sciences, Seoul National University) ;
  • Yoon, Young-Ho (KCI Ltd.) ;
  • Yang, In (Research Institute for Agriculture and Life Sciences, Seoul National University)
  • 오세창 (대구대학교 생명환경대학 산림자원학과) ;
  • 안세희 (대구대학교 생명환경대학 산림자원학과) ;
  • 최인규 (서울대학교 농업생명과학대학 산림과학부 환경재료전공) ;
  • 정한섭 (서울대학교 농업생명과학대학 산림과학부 환경재료전공) ;
  • 윤영호 ((주) KCI) ;
  • 양인 (서울대학교 농업생명과학연구원)
  • Received : 2008.01.07
  • Accepted : 2008.02.11
  • Published : 2008.05.25
Download PDF
⟨ Previous Next ⟩

Abstract

Petroleum-based resin adhesives have extensively been used for the production of wood panels. However, with the increase of manufacturing cost and the environmental issue, such as the emission of volatile organic compounds, of the adhesive resins, it is necessary to be developed new adhesive systems. In this study, the potential of okara, which is a residue wasted from the production of tofu, for the development of bio-based adhesives was investigated. At first, the physical and chemical properties of okara were examined. After okara was hydrolyzed in acidic and/or alkaline solutions, okara-based adhesive resins were formulated with the mixtures of the okara hydrolyzates and phenol formaldehyde (PF) prepolymer. The adhesive resins were used for the fabrication of plywood panels, and then the adhesive strength and formaldehyde emission of the plywood panels were measured to examine the applicability of the resin adhesives for the production of plywood panels. The solids content and pH of the okara used in this study were around 20% and weak acidic state, respectively. In the analysis of its chemical composition, the content of carbohydrate was the highest, and followed by protein. The shear strengths of plywood fabricated with okara-based resin adhesives exceeded a minimum requirement of KS standard for ordinary plywood, but its wood failure did not reach the minimum requirement. In addition, the formaldehyde emissions of all plywood panels were higher than that of E1 specified in the KS standard. Based on these results, okara has the potential to be used as a raw material of environmentally friendly adhesive resin systems for the production of wood panels, but further researches - biological hydrolysis of okara and various formulations of PF prepolymer - are required to improve the adhesive strength and formaldehyde emission of okara-based resin adhesives.

현재 국내에서 목질계 판상재를 생산하기 위해 사용되고 있는 석유화학계 접착제의 제조비용 상승과 포름알데히드 방산 문제로 대체 접착제의 개발이 필요한 상황이다. 따라서 본 연구에서는 대체 접착제 개발 방안의 하나인 bio-based 접착제 개발을 위하여 유기폐기물인 두부비지의 원료화 가능성을 확인하였다. 먼저 두부비지의 이화학적 성질을 조사하였고, 두부비지를 황산 또는/그리고 가성소다로 화학적으로 개량한 후 phenol formaldehyde (PF) prepolymer와 혼합하여 접착제를 조제하였으며, 그 접착제를 합판 제조에 사용하였다. 또한 제조된 합판의 접착강도 및 포름알데히드 방산량을 측정하여 합판용 접착제로서 사용가능성을 확인하였다. 본 연구에서 원료로 사용된 두부비지의 고형분 함량 및 pH는 각각 20% 내외, 약산성이었으며, 화학적 조성은 탄수화물의 함량이 가장 높았으며 다음으로 단백질을 많이 함유하고 있었다. 두부비지를 이용하여 조제된 접착제를 이용하여 제조된 합판의 인장전단강도는 KS 규격의 보통합판 품질기준을 상회하였으나, 목파율은 기준에 비해 낮은 것으로 조사되었다. 또한 포름알데히드 방산량도 KS 규격의 E1 기준보다 높은 것으로 나타났다. 따라서 두부비지가 환경친화적인 목질계 판상재료용 접착제의 원료로서 사용될 수 있다는 가능성을 보여 주었으나 접착강도의 향상과 포름알데히드 방산량 저감을 위해 두부비지의 생물학적 개량방안과 가교제로 사용된 PF prepolymer에 대한 좀 더 많은 연구가 필요하다.

Keywords

References

  1. 한국산업규격. 2006. 보통합판 KS F 3101.
  2. 환경부. 2003. 다중이용시설등의 실내공기질 관리법. 법률 제 6911호.
  3. Lambuth, A. L. 1989. Adhesives from renewable resources ; Historical perspective and wood industry needs. In Adhesives from Renewable Resources, ACS Symposium Series 385: 1-10 American Chemical Society. WA. D.C. https://doi.org/10.1021/bk-1989-0385.ch001
  4. Ma, C. Y., W.-S. Liu, K. C. Kwok, and F. Kwok, 1997. Isolation and characterization of proteins from soymilk residue (okara). Food Res. Inter. 29: 799-805.
  5. O'tool, D. K. 1999. Characteristics and use of okara, the soybean residue from soy milk production-A review. J. Agric. Food Chem., 47(2) : 363-371. https://doi.org/10.1021/jf980754l
  6. Pizzi, A. and H. O. Scharfetter. 1978. The chemistry and development of tannin-based adhesives for exterior plywood. J. of Applied Polymer Science. 22(6): 1745-1761. https://doi.org/10.1002/app.1978.070220623
  7. United Soybean Board. 2004. Soy-based wood adhesives. Market Opportunity Summary, Jan. 2004.
  8. Van der Riet ,W. B., A. W. Wight, and J. M. Datel. 1989. Food chemical investigation of tofu and its byproduct okara. Food Chemistry 34: 193-202. https://doi.org/10.1016/0308-8146(89)90140-4
  9. Yang I., M. L. Kuo, D. J. Myers and A. Pu. 2006. Protein-based wood adhesive resins for wood panels. J. of Wood Science. 52 : 503-508. https://doi.org/10.1007/s10086-006-0804-5
  10. Yang, I., M. L. Kuo, and D. J. Myers. 2005. Physical properties of hybrid poplar flakeboard bonded with alkaline phenolic soy adhesives. J of the Wood Science and Technology. 33(5) : 66-75.