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Official Journal of the Japan Wood Research Society

Journal of Wood Science Cover Image

Table 3 Fibrillated bark adhesive composition and bonding quality from the continuous 72-h boiling test (JAS)

From: Development of bark-based adhesives for plywood: utilization of flavonoid compounds from bark and wood. II

Adhesives1 CF-B 2-1 2-2 2-3 2-4 2-5 2-6
Mass ratio
 PF resin (solids) 100 70 60 50 40 30 20
 Fibrillated bark 0 30 40 50 60 70 80
 Wheat flour 22 0 0 0 0 0 0
 Other solid components 48 0 0 0 0 0 0
Total solids content (%) 55 39 33 30 27 24 21
Viscosity (Pa·s) (23 °C) 1.4 3.1 2.5 2.7 3.1 2.2 2.8
pH 11.8 10.8 10.3 9.9 9.6 9.1 8.3
Gelation time (min) (135 °C) 9.5 8.0 7.0 5.5 7.0 9.0 9.5
Reactive components in adhesive (%)
PF resin contents 32.0 27.3 19.8 15.0 10.8 7.2 4.2
Polyflavanoids contents 0.0 6.2 6.9 7.9 8.5 8.9 8.9
Bonding test results
Number of panels 4 4 4 4 3 4 4
Number of specimens 32 32 32 25 24 31 32
Average of shear strength (MPa)2 0.84 ± 0.21b 1.04 ± 0.28a 1.13 ± 0.30a 0.74 ± 0.15b 0.71 ± 0.13b 0.74 ± 0.24b 0.70 ± 0.13b
Average wood failure ratio (%)2 87.2 ± 9.9a 89.1 ± 15.5a 90.9 ± 13.3a 72.0 ± 33.3a 32.5 ± 35.3b 21.9 ± 25.6b 27.8 ± 28.6b
Judgment of test results (JAS)3 PASS PASS PASS PASS PASS PASS PASS
  1. 1“CF-B” means “Commercial formulation B” and refers to the formulation of a commercial adhesive for plywood using PF resin B
  2. 2Results are given as the mean ± standard deviation. ANOVA showed that the means are significantly different (p < 0.001). Means having the same letter (a, b) within a row are not significantly different as determined by the Tukey’s test (p < 0.05)
  3. 3“PASS” means met the criteria of JAS