New method for rapid testing of bond strength for wood adhesives

Abstract

In developing new adhesives for wood bonding, the testing of bond performance can often be a limiting factor in the development process. Evaluating the bond performance of an adhesive that can be prepared in less than a day often takes several days using standard performance tests. This testing slows the development process and may cause a company to abandon a commercially viable product due to development costs or to offer a product commercially that has not been fully developed. Furthermore, some of the standard tests provide only qualitative data on a pass/fail basis, making it difficult to determine whether changes resulted in better or worse performance. This has led to an interest in developing a faster quantitative screening test for wood bonding. Most wood adhesives use pressure and heat to form a strong bond. Humphrey has developed the Automated Bond Evaluation System (ABES) for determining the rate of strength development of wood adhesives as they cure (1). This equipment allows for accurate control of bonding pressure, platen temperature, and bonding dwell time and good alignment of the lap shear samples. Given the speed with which samples can be prepared using the ABES, which also provides highly controlled times, temperatures, and pressures, this study was aimed at investigating the use of this equipment for the rapid preparation of heat-cured bonded wood lap shear specimens. The samples could then be removed from the ABES while still intact, equilibrated in a controlled environment, and finally tested dry or wet using a standard tensile testing machine, which is designed to provide absolute strength values. The results involved not only the use of this method for development of new soy flour adhesives but also a comparison of other adhesives to the results from the standard plywood tests ANSI/HPVA HP-1-2004 4-6 (hereafter referred to as HP1) (2) for interior or decorative plywood and Voluntary Product Standard PS 1-95 6.1.5.1 and .2 (hereafter referred to as PS 1-95) for exterior plywood (3).

Citation

Wescott, James M.; Birkeland, Michael J.; Traska, Amy E.; Frihart, Charles R.; Dally, Brice N. 2007. New method for rapid testing of bond strength for wood adhesives. Proceedings : 30th annual meeting of the Adhesion Society, Inc. : February 18-21, 2007, Tampa Bay, FL. [S.l. : s.n.], c2007: pages 219-221.