The use of coffee bean post-extraction residues as a filler in plywood technology

The use of coffee bean post-extraction residues as a filler in plywood technology. The aim of the research was to determine the influence of post-extraction coffee beans used as a glue mass filler for the plywood glue joint on their selected mechanical and physical features. In the scope of the research the plywood of different content of post-extraction coffee beans in glue mass have been produced in laboratory conditions, as well, as reference material, the plywood with wheat flour as a glue mass filler have been made. The investigated material has been tested according to different features, including measurement of the plywood density profile, static bending strength and modulus of elasticity, shear strength, water absorption, as well as resistance to axial removal of screws. The significant reduction of bending strength, modulus of elasticity when bending, shear strength, as well as resistance to axial removal of screws has been found for samples with coffee bean residues, when referred to reference plywood. Also, decreasing penetration depth of coffee residues filled glue mass has been noted, with the coffee bean post-extraction residues content raise.