Adhesives | CF1 | 1 | 2 | 3 | CF1 | 1 | 2 | 3 |
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Mass ratio |
PF resin (solids) | 100 | 60 | 50 | 40 | 100 | 60 | 50 | 40 |
Fibrillated bark slurry (solids) | 0 | 40 | 50 | 60 | 0 | 40 | 50 | 60 |
Wheat flour | 15 | 0 | 0 | 0 | 15 | 0 | 0 | 0 |
Other solid components | 22 | 0 | 0 | 0 | 22 | 0 | 0 | 0 |
Total solids content (%) | 55 | 34 | 30 | 27 | 55 | 34 | 30 | 27 |
Viscosity (Pa s) (23 °C) | 1.6 | 1.9 | 1.6 | 2.1 | 1.7 | 1.9 | 1.6 | 2.1 |
Bonding test results |
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Plywood species | Hinoki (Japanese cypress) | Karamatsu (Larix species) |
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Number of panels | 4 | 4 | 4 | 4 | 4 | 1 | 2 | 3 |
Number of specimens | 32 | 32 | 32 | 32 | 32 | 8 | 16 | 24 |
Average of shear strength (MPa)2 | 1.02 ± 0.37a | 1.18 ± 0.28a | 1.24 ± 0.37a | 1.17 ± 0.39a | 1.05 ± 0.33a | 0.98 ± 0.34a | 0.86 ± 0.36a | 0.87 ± 0.24a |
Average wood failure ratio (%)2 | 93.8 ± 5.5a | 23.1 ± 33.2c | 21.9 ± 25.3c | 47.5 ± 35.6b | 94.4 ± 8.4a | 95.0 ± 8.7a | 21.8 ± 17.6b | 47.5 ± 30.3b |
Judgment of test results (JAS)3 | PASS | PASS | PASS | PASS | PASS | PASS | PASS | PASS |
- 1“CF” means “Commercial formulation” refers to a composition of a commercial adhesive using PF resin for plywood
- 2Results are given as the mean ± standard deviation. ANOVA for analysis of variance showed that the means are significantly different (p < 0.001). The same letter within a row are not significantly different as determined by the Tukey’s test (p < 0.05)
- 3“PASS” means met the criteria of JAS