Three-layer particle board

Three-layer particle board is essentially a core of larger particle sizes, with increasing density, smaller particle sizes and more resin moving outwards to the edges. This design forms three layers, two with a denser product about a quarter of the depth or less on each side and less dense core with larger chips making up around half of the total thickness. Although the product is described as three layers the three merge into a single mass, though the difference can be seen visually at the sides. It is a heavy weight product and more durable than other particle boards with some external applications.

Standard particle board was originally made in late 19th century Germany, then produced commercially around the Second World War. The earlier board products were often made using blood albumin glue, whilst later commercial products used phenolic resins, amino formaldehyde-, urea formaldehyde-, or urea melamine-based, today there are also particle board products that use glues with lesser environmental impacts. Three-layer particle boards were introduced some time later as a method to reduce the volumes of glue and wood used, whilst retaining most of the same characteristics of a denser board but also increasing weathering capabilities because the external surfaces hace higher resin content.

All particle boards comprise of a small chips and flakes of softwood of varying sizes and density that are impregnated with adhesive (usually amino formaldehyde-, urea formaldehyde-, or urea melamine-based) and subjected to high temperature (up to 220°C) and pressure (2-4MP). When cooled, the boards are cut and sanded, sold either as plain board or faced with laminate. In three-layer particle board the core is first pressed at a lower density, around 600 kg/m3, then the it is sandwiched between two layers of denser particles, around 700-800 kg/m3, containing more binding agent.

Three-layer particle boards can show the same uniformity, as standard particle boards but have the characteristics of denser boards, whilst saving material. The product can be sealed, it is not usually used for external applications but may be suitable for flooring applications.

Normal hand or machine tools can be used for working with three-layer particleboard, it usually take screws similar to denser grades.

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