Objective
The project major technical achievements were:
Wax microparticles produced in the spray dryer and containing less hydrophilic hardeners than ammonium sulphate, showed reactivity at 80 C identical to it and the hardener release at 40 C (pot life) was significantly delayed by the encapsulation. Although these hardeners were more reactive than ammonium sulphate, it was made possible to achieve latency significantly larger than that of ammonium sulphate by employing encapsulated formulations of the above hardeners into wax microparticles.
Wax capsules containing a hydrophilic hardener, which were produced using the hot melt fluidized bed process, provided latency behaviour better than ammonium sulphate and have been used both at lab and at the industrial scale in particleboard and plywood production. Using urea as a base core material, the capsules behave both as resin hardener and as formaldehyde scavenger, thus solving simultaneously the formaldehyde emission problem. The method is very flexible and can be used for the confinement of either liquid or solid hardeners/formaldehyde scavengers or any other useful ingredients, e.g. fire retardants.
Several compounds of promise were identified as potential latent hardeners and studies on the production of particleboards using these hardeners were carried out.
The use of superabsorbent polymer in cork production led to a significant reduction of the residence time of the cork blocks in the press, without significant loss in block properties. This reduction amounts to about 27% for pilot scale blocks and about 18% for industrial scale blocks.
Engineered panel products are made with particles or fibers bonded together with an adhesive under controlleed heat and pressure. Urea-formaldehyde water-based dispersions are the most widely used binders. The cure of the adhesiveis accomplished by the use of catalysts (usually called hardeners) which are conventionally salts generating acidity. The final polymerisation of the adhesive occurs in the hot press and is one of the critical steps in the manufacturing process. If the adhesive cures at any point in the manufacturing sequence other than in the hot press where the mat is compressed to the desired thickness, a weak product (referred to as precured) will be produced. With conventional hardeners some precure is inevitable. The proposal addresses this problem. A latent catalyst will be developed, which will be active at the pressing temperature (100°C) but inactive at lower temperatures. This catalyst will allow faster curing times and therefore shorter press-cycles (and increased productivity). Moreover, by using with the hardener a chemical that takes up water, we solve the problem of high panel moisture content experienced in many mills. The water interferes with the condensation polymerisation reaction of the curing resin, acting as a retarder. Also, the press time has to be sufficiently long to allow the steam to escape smoothly to prevent delamination. By removing part of the core moisture the new hardener will allow shorter press-cycles without delamination.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- engineering and technologymechanical engineeringmanufacturing engineering
- engineering and technologymaterials engineeringfibers
- natural scienceschemical sciencesorganic chemistryaldehydes
- social scienceseconomics and businesseconomicsproduction economicsproductivity
- natural scienceschemical sciencescatalysis
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Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
57011 GEPHYRA THESSALONIKIS
Greece