Optimization and practical application of cottonseed meal-based wood adhesive formulations for small wood item bonding

Abstract The interest in biobased wood adhesives has steadily increased in recent years. Our previous studies have shown that water-washed cottonseed meal (WCSM) could be used as low-temperature and high-solid content biobased wood adhesives for non-structural bonding as European Standard Class D1 adhesives. In this work, we optimized WCSM-based adhesive formulations with high solid contents up to 49% for bonding of small wood items at low temperatures (40 °C). Chemical denaturing reagents guanidine hydrochloride (GdmCl) and sodium dodecyl sulfate (SDS) were added to improve the bonding capability and viscosity of WCSM. Reviewing industry preferences, four formulations with 20% and 30% of WCSM as well as 9.6% and 19.1% of SDS were used to glue “real world” pencil slat sandwiches for pencil making. All the pencils made from these sandwiches bonded at 40 °C and 1 MPa for 120 min passed the Industrial Temperature Cycle test. The results indicated that WCSM could be used as a low temperature wood adhesive, possibly for the domestic furniture and small utensils niche markets. The pencil sandwich bonding represents a specific application that could benefit from the non-toxic glue and also be an example of an interior application.