节子对落叶松胶合木胶合性能的影响

Influence of knot on the agglutination properties of Chinese larch glulam

采用水性高分子一异氰酸酯（API）胶黏剂对含有木节的兴安落叶松（如成gmelinii）层板按照工程胶合木的胶合工艺进行常温加压胶合，探讨木节及其大小对兴安落叶松工程胶合木胶合性能的影响。通过对试件进行胶缝剪切强度试验和浸渍剥离与煮沸剥离试验，发现节子对胶缝常态剪切强度、木破率、浸溃剥离率和煮沸剥离率均有显著的影响，随着木节直径的增大其胶缝剪切强度和木破率可下降40％和67％以上，浸渍二次总剥离率和煮沸二次总剥离率可增大至16％和37％以上。研究表明：两胶合面中仅一面有小木节（占板宽1／7～1／6），只能用于室内结构用集成材，不能用于室外结构用集成材；只有尺寸小于木板宽度1／10的木节与无节面胶合才能满足室外用工程胶合木的要求。

The effects of knot and its size on the agglutination properties of Chinese larch engineering wood were exploredby applying aqueous polymer-isocyanate （API） adhesive in the bonding process of Chinese larch （Larix gmelinii ）glulam with knots at normal temperature. The results of glue line shear strength test, immersion delamination and boilingdelamination test showed that the knots had significant influences on the normal shear strength of glue line, failure per-centage of wood, immersion delamination percentage and boiling delamination ratio. With the increasing of knot＇ sdiameter, the shear strength of glue line and wood failure percentage decreased more than 40% and 67%, respectively,the total re-immersion delamination percentage and re-boiling delamination ratio could be increased more than 16% and37%, respectively. The research results indicated that ： those bonding surfaces composed by knot free panel and anotherwith small knot accounted for the 1/7 to 1/6 of board＇ s width could only be used indoor due to the incompetence of totalre-boiling stripping rate of glue-line. At the request of the glue-line total re-boiling stripping rate less than 5%, onlythose bonding surfaces composed by knot free panel and another with knot＇ s dimensions less than 1/10 of board＇ s widthcould be used for manufacturing the outdoor engineering glulam.