Wood is an indispensable material, and we can find it on the market in a multitude of formats and qualities. Among the many processed wood formats that exist, we find those of particle and fiber boards, also known as wood chipboards, or in the case of the latter, MDF.
This processed wood format has become very specialized in the last few decades, since it is versatile, allows a great use of the wood and has a relatively low cost.
Wood chipboards are made from woodchip pieces. They admit different particle sizes, so that you can take advantage of many tree varieties without depending too much on log diameter, even the sawdust from other processes can be reused for the creation of wood chipboards. Therefore, not only does it use waste and wood debris derived from the industry, but it is also an incentive to clean the undergrowth of forests for its use, contributing to improving their quality and reducing the risk of fires. Its production process can be summarized in three phases: the preparation of the raw materials, the shaping of boards and then the finishing.
To start, the wood logs are inserted into a machine that aims to eliminate the smallest amount of bark required, in a rotating cylinder using friction. If the bark is not eliminated, the quantities that may be left in the process cause an increase of energy required during drying. Next, a machine is used to shred the log into small chips, which after passing through a sieve that separates the particles that are too thick, go into a silo. The thick chips can be shredded again to reintroduce them into the process or even for making fiberboards. Those that have passed through the sieve are broken down into even smaller particles in metal blade mills to obtain wood particles with thicknesses from a tenth of a millimeter and up to 30 mm in length. The particles, are temporarily stored in silos. Next comes the drying, which is done by direct contact with hot air in large cylinders through forced circulation, keeping the particles in suspension for full contact with the air. Dried particles are filtered again to eliminate dust and very fine particles through cyclones, and separate the bigger particles from the small ones through a new sieving process. Those smaller ones will be used to make the faces of the board.
After the wood particles have been dried and classified by size they are subjected to the gluing process. Compressors are used to spray the glue in very small particles so that it is evenly as much as possible between pieces of wood.
The most commonly used glue in the manufacture of chipboards is urea formaldehyde. Melamine and Phenol Formaldehyde glues are used in some specific cases due to their resistance to moisture. Once the appropriate amount of glue has been applied, the finest particles are projected on a surface that will form one of the faces of the board, then the larger particles are laid down to create what will be the interior of the board. Finally a layer of fine particles is laid down on top to seal the board.
Before shaping and pressing, it undergoes quality controls to avoid metals or other unforeseen materials that can cause imperfections in the machining. The chipboard sandwich passes a first cold pressing to facilitate its transport. Prior to the pressing process, water is sprayed on the surface to facilitate the thermal transmission during the polymerization of the glue. The press process can be continuous by means of rollers or by means of perpendicular homogeneous pressure on the surface. It is important to incorporate demolding products so that the rollers or presses do not adhere to the glue to prevent particle removal from the surface, since this can cause irregularities in the density of the board and damage to the surface.
Immediately after the press and before the board is cooled, a first stage of board cutting is performed. Later will come the cooling and subsequent mechanical treatments for finishes. Using circular saws, the size of the resulting boards will be defined and the outer sides are sanded to ensure a smooth surface.
Concentrol has developed a line of water-based release agents CONCENTROL LX WP-MDF-LINE, which are used in the production of wood chipboards. The release agents are designed to provide high performance in the pressing stage and can be used for various adhesives and production methods.
The CONCENTROL LX WP-MDF-LINE provides excellent efficiency against the usual adhesives based on urea and melamine resins, it is composed of emulsified waxes and resins, it can be easily applied and the possible remains of the product are easily eliminated and safe for use by the operator.
The composition of our products are compatible with rubber elements that can be present on the machines, while protecting the press rollers by extending the useful life of the machinery. Our products are designed for high performance and are stable at a wide range of pressing temperatures. The products are inert to colorations and are therefore ideal in the production of sensitive or soft-coloured processed woods. The produced boards can be easily painted, while at the same time paint consumption can be significantly reduced.
Concentrol is a chemical company with over 75 years of experience providing solutions with high performance and excellent value for money. One of Concentrol’s main product divisions is mold release agents. Concentrol’s strong commitment to innovation in developing new products that adapt to the needs of each industry and the regulations of each territory make it one of the leading companies in the sector. Contact us for further information.
