Particle board is a wood-derived material manufactured by combining and pressing small particles, chips, shavings, or wood fibers mixed with synthetic adhesives, generally thermosetting resins, at high temperatures and pressures.
Raw Materials Used
Primarily softwoods such as conifers, especially pine, are used. Fast-growing woods like poplar or eucalyptus are also common. The composition can include recycled wood and remnants from sawing processes, and even burned wood from fires. The wood can come from logs, pallet remnants, and other forest waste that is not used for solid wood.
Adhesives and Additives
Thermosetting resin adhesives (for example, aminoplastic resins) are used. Additives can be incorporated to improve specific properties:
- Water-repellent additives for moisture resistance.
- Fire-retardant additives to slow down the action of fire.
- Colorants for identification:
- Green in water-repellent boards.
- Red in fire-retardant boards.
Formaldehyde is present as part of the adhesive resins, although its content has been reduced to very low levels (classes E1 or even E0.5) to minimize toxicity risks.
Manufacturing Process
- Crushing and selection of particles: The particles are crushed and selected according to size and quality.
- Mixing particles with adhesives: The particles are mixed with adhesive resins and other additives.
- Formation of the mat: A thick layer of larger particles is placed in the center and thin layers on the surface, forming a multi-layer structure.
- Pressing: The mixture is subjected to high pressure and temperature, which polymerizes the resin and solidifies the board.
- Cutting and finishing: The boards are cut to size, sanded, and can be coated with melamine, laminates, wood veneers, or paints.
Board Structure
- Central core formed by coarser wood particles.
- Outer layers with fine particles, higher density, and resin proportion to obtain smooth surfaces suitable for finishes.
- Typically a "three-layer" structural architecture.
Technical and Mechanical Properties
| Property | Range / Value | Details |
|---|---|---|
| Density | 550 - 820 kg/m³ depending on the type and thickness | Density decreases with increasing thickness; 650-690 kg/m³ common in thicknesses of 16-19 mm |
| Dimensional stability | High | Does not deform easily in dry conditions |
| Modulus of Elasticity | ~ 400 N/mm² (varies depending on density and quality) | Measure of stiffness |
| Flexural strength | 10-11 MPa (P1 and P2) | P2 is more resistant (11 MPa) than P1 (10 MPa) |
| Screw load resistance | 3-5.5 kg/mm screw length | Higher on the surface than on edges |
| Formaldehyde content | According to EN 120 standard; low values in E1, E0.5 | CLASSES: E2 (not suitable for residential use), E1 (low content), E0.5 (minimum formaldehyde) |
| Thermal conductivity | 0.15 W/(m·K) | Low thermal insulation capacity |
| Water vapor permeability | 0.13 mg/(m·h·Pa) | Does not act as a vapor barrier, allows transpiration |
| Biological resistance | High | Not attacked by insects or fungi, although it can swell with moisture |
| Combustibility group | G4 (wood) | Burns, but does not spread fire easily |
Classification and Types of Particle Board
Particle boards are classified based on their treatments and properties:
- Standard (P1/P2)
- Basic board without special additives.
- Mainly used for furniture and interior construction in dry environments.
- Water-Repellent Particle Board
- Contains additives that offer better resistance to moisture.
- Identified with green dye.
- Suitable for kitchens, bathrooms, and environments with high humidity, although not waterproof.
- Its resistance is still limited against prolonged water exposure.
- Fire-Retardant Particle Board
- Incorporates fire-retardant additives.
- Identified with red dye.
- Used in public buildings, hotels, and offices with demanding safety regulations.
- Lightweight Particle Board
- Lower weight by incorporating synthetic polymers along with wood particles.
- Used to manufacture lightweight parts such as doors.
- Coated or Laminated Particle Board
- Covered with decorative paper impregnated with melamine resins (melamine), plastic laminates (HPL), or natural wood veneers (veneered).
- Improves aesthetics, durability, and resistance to wear and surface moisture.
- High-Density Fiberboards (HDF)
- Greater compaction for superior strength and durability.
- Used in laminate flooring and decorative panels.
Common Dimensions and Thicknesses
- Common dimensions:
- 2440 x 1220 mm (most frequent)
- 2850 x 2100 mm
- 2440 x 2500 mm
- 3660 x 2050 mm
- Available thicknesses: 5, 8, 10, 13, 15, 16, 18, 19, 20, 22, 23, 25, 26, 30, 31 mm.
- Most common for furniture: 10, 16, 19, 22, 30 mm.
Environmental and Health Aspects
Efficient use of wood, taking advantage of waste and recycling, reduces waste between 60% and 10% compared to solid wood. It is sensorially biodegradable and environmentally friendly if low-emission adhesives (E1 or better) are used. Mass production and the use of waste make it a sustainable and responsible option. Formaldehyde emission should be considered, adapting the board to the end use (homes, schools require classes E0.5 or E1).
Comparison with Other Similar Materials
- MDF (Medium Density Fiberboard):
- Manufactured with much finer wood fibers than particle board.
- Much smoother, more uniform surface with a finer feel, ideal for fine finishes and varnishes.
- Better for curved and molded machining, as it is more malleable.
- Particle board has the advantage of lower price and greater rigidity for straight lines.
- Solid wood:
- More natural, resistant, and aesthetic, but more expensive and less sustainable.
- OSB (Oriented Strand Board):
- More oriented to construction, not so used in furniture.
Functional Properties and Use
Advantages
- Excellent value for money.
- Ease of machining: cutting, drilling, milling with standard machinery.
- Wide variety of decorative finishes (melamine, veneers, lacquers).
- Lightweight material (compared to solid wood), facilitating transport and assembly.
- Dimensionally stable in a dry environment, resisting deformation.
- High biological resistance to fungi and insects.
- Efficient and sustainable use of forest resources.
Disadvantages
- Sensitive to moisture, swells irreversibly if wet (less of a problem if water-repellent).
- Not suitable for outdoor use without proper treatment.
- Surface not 100% smooth (although greatly improved in thin outer layers).
- Edges must be protected (edged or veneered) to prevent chipping and moisture damage.
- Formaldehyde content, although reduced, requires certification according to use.
- Not repairable if damaged or swollen.
Main Applications
- Manufacture of interior furniture: cabinets, kitchens, shelves, dressers, desks, shoe racks, office furniture.
- Interior carpentry: doors, countertops, coverings, and paneling.
- Interior cladding: ceilings, walls, partitions, laminate flooring (with melamine or laminates such as HPL).
- Divisions and screens in offices or commercial premises.
- Base for formwork and auxiliary structures in construction.
- Laminate floors and pavements in high-density versions (HDF).
Additional Technical Details
The width and thickness of the board influence the density and resistance: the greater the thickness, the lower the density of the board. Flexural strength and elasticity depend on the density and manufacturing process. Screw extraction resistance is a key parameter in mechanical assemblies. Thermal conductivity and vapor permeability are relatively low, so they provide some insulation but should not be considered primary insulators.
Visual Summary of the Composition
| Component | Description | Function |
|---|---|---|
| Wood particles | Chips, shavings of softwoods or recycled woods | Basic structural material |
| Resin adhesives | Thermosetting resins (aminoplastics, melamines) | Bonding and cohesion of particles |
| Additives | Fire retardants, moisture repellents, colorants | Specific functional improvements |
| Thin outer layers | Small particles + higher proportion of resin | Smooth surface suitable for finishing |
| Edging/veneering (optional) | PVC, wood veneers, or other material | Protection and finishing of edges |
The particle board is a composite of wood particles, adhesives, and sometimes additives, pressed together to form a solid panel. The specific composition and manufacturing process determine its properties and applications.