At-line validation of a process analytical technology approach for quality control of melamine-urea-formaldehyde resin in composite wood-panel production using near infrared spectroscopy
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The reactivity of melamine-urea-formaldehyde resins is of key importance in the manufacture of engineered wood products such as medium density fibreboard (MDF) and other wood composite products. Often the MDF manufacturing plant has little available information on the resin reactivity other than details of the resin specification at the time of batch manufacture, which often occurs off-site at a third-party resin plant. Often too, fresh resin on delivery at the MDF plant is mixed with variable volume of aged resin in storage tanks, thereby rendering any specification of the fresh resin batch obsolete. It is therefore highly desirable to develop a real-time, at-line or on-line, process analytical technology to monitor the quality of the resin prior to MDF panel manufacture. Near infrared (NIR) spectroscopy has been calibrated against standard quality methods and against 13C nuclear magnetic resonance (NMR) measures of molecular composition in order to provide at-line process analytical technology (PAT), to monitor the resin quality, particularly the formaldehyde content of the resin. At-line determination of formaldehyde content in the resin was made possible using a six-factor calibration with an R2(cal) value of 0.973, and R2(CV) value of 0.929 and a root-mean-square error of cross-validation of 0.01. This calibration was then used to generate control charts of formaldehyde content at regular four-hourly periods during MDF panel manufacture in a commercial MDF manufacturing plant.
KeywordsProcess analytical technology PAT Near infrared spectroscopy NIR Melamine-urea-formaldehyde resin MUF
- 1.California Air Resources Board. Airborne toxic control measure to reduce formaldehyde emissions from composite wood products. Sections 93120–93120.12, title 17, California Code of Regulations 2008.Google Scholar
- 2.Valdez D, Nagy E. Analyses/testing. In: Pilato L. Phenolic resins: a century of progress. Springer 2010, 545 pp, ISBN 978-3-642-04713-8.Google Scholar
- 5.Zhang J, Wang X, Zhang S, Gao Q, Li J. Effects of melamine addition stage on the performance and curing behavior of melamine-urea-formaldehyde (MUF) resin. BioResources. 2013;8(4):5500–14.Google Scholar
- 6.Vanerek J, Benesova A, Rovnanik P. Influence of different mixing ratios of adhesives for wood bondline quality. Int J Chem Mol Nucl Mater Metall Eng. 2012;6(10):942–5.Google Scholar
- 9.Tomita B, Hatono S. Urea-formaldehyde resins. III. Constitutional characterization by 13C Fourier transform NMR spectroscopy. J Polym Sci. 1978;16:2509–25.Google Scholar
- 17.Pawliczek M, Reischer T, Kowalski J, Märzinger W, Kantner W, Brandstetter M. Long-term monitoring of melamine formaldehyde resins using NIR spectroscopy. Lenzinger Berichte. 2015;95:47–52.Google Scholar
- 19.Pemberger N, Bittner LKH, Huck CW. Using near-infrared spectroscopy to monitor the curing reaction of silicone adhesives. Spectroscopy. 2015;30:8–19.Google Scholar
- 20.Gaspar F, Lopes J, Cruz H, Schwanninger M, Rodrigues J. Application of near infrared spectroscopy and multivariate data analysis for the evaluation of glue lines of untreated and copper azole treated laminated timber before and after aging. Polym Degrad Stabil. 2009;94:1061–71.CrossRefGoogle Scholar
- 22.Meder R, Ebdon N, Warburton P, Stahl W, Woolley S, Earnshaw S, Haselhofer K, Grayston G, van Langenberg K. NIR assessment of MUF resin quality for composite panel production. Forest and Wood Products Australia Report PNB169-0809, 2009, 65 pp. Report accessed 21/10/16 http://www.fwpa.com.au/images/processing/PNB169-0809_Final_Report_0.pdf.
- 23.Workman J Jr, Weyer L. Practical guide and spectral atlas for interpretive near-infrared spectroscopy. 2nd Ed. Boca Raton: CRC Press, 2012, 309 pp, ISBN 978-1-4398-7525-4.Google Scholar
- 25.Humphrey PE. A device to test adhesive bonds. 1993 US Patent 5,170,028.Google Scholar
- 26.Pizzi A, Mittal KL. Handbook of adhesive technology. 2nd ed. 2003.Marcel Dekker, NY. 1017 pp, ISBN 0-8247-0986-1.Google Scholar