Study on bonding properties of Larch with WPI adhesive

Abstract

Purpose

The purpose of this paper is to study the bonding properties of Larch with water‐based polymer isocynate (WPI) adhesive to provide theoretical instruction for practical production of Larch glued laminated timber with WPI adhesive.

Design/methodology/approach

This study adopted Japanese JIS K6806 standard to test bonding properties of Larch with WPI adhesive. Scanning electron microscope was used to observe morphography of Larch surface. Micro photos were adopted to show the penetration of WPI adhesive on the radial and tangential surfaces of Larch.

Findings

There was significant difference in bonding strength between Larch radial and tangential glue‐blocks glued with WPI adhesive. Dry compressing shear strength of Larch radial glue‐block bonded with WPI adhesive was 1.41 times that of Larch tangential glue‐block bonded with WPI adhesive in normal conditions. Wood failure showed that the difference between Larch radial and tangential glue‐block was caused by wood structure of Larch itself.

Research limitations/implications

The research conclusion that the dry compressing shear strength of Larch radial glue‐block bonded with WPI adhesive was bigger than that of Larch tangential glue‐block bonded in normal conditions. These would be changed if other adhesives were adopted to glue Larch wood.

Practical implications

The conclusion developed in this study provided a practical production instruction for Larch glued laminated timber with WPI adhesive. In order to obtain better bonding properties during the production of Larch glued laminated wood, Larch wood should be sawn into radial boards rather than tangential boards in order to obtain maximum bonding strength of Larch wood.

Originality/value

The paper shows that there was significant difference in bonding strength between Larch radial and tangential glue‐bonded blocks with WPI adhesive. Dry compressing shear strength of Larch radial glue‐block bonded with WPI adhesive was 1.41 times that of Larch tangential glue‐block bonded with WPI adhesive in normal conditions.

Citation

Cheng, R.X. and Gu, J.Y. (2010), "Study on bonding properties of Larch with WPI adhesive", Pigment & Resin Technology, Vol. 39 No. 6, pp. 359-364. https://doi.org/10.1108/03699421011085867