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| PDF : |  10050188.pdf |
| title(En) : | Studies on the Powdered-Dry Bonding Process in the Manufacture of Plywood. II. On the Influences of Water on the Adhesion |
| author(En) : | Atsuo Tanaka |
| information : | Mokuzai Gakkaishi 10(5), 188-192 (1964) |
| assort : | Original Article |
| summary(En) : | The dry powdered urea resin adhesive is not fusible even at 240°C, but it was previously found in the report I that this dry-bonding method can be applied to temperature setting as low as about 40°C. Therefore, in this study the influence of water on the characteristics of urea resin and the strength of adhesion were investigated. By this method a good strength of adhesion was obtained over a wide range of moisture contents 5∼25% in veneers, and even with still higher contents the failure of adhesion by the puncture of veneers was removed merely by using much bigger amount of glue spread. It was found that urea resin was not fused by heat but dissolved in water contained in wood, and as this result the wettability to wood was obtained. Having in mind the ratio of total water to urea resin in the glue layer, it seems that the mechanism of adhesion in this method is not essentially different from that of the liquid type, and the excellent features discussed in the report I are due to the low water ratio. |