Particle board-

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Slide 1: 

BY N.KANAGARAJ BSF-06-007

PARTCLE BOARD : 

PARTCLE BOARD The particle board is a board or sheet constitute from fragments of wood and other ligno-cellulosic material, bonded with organic binder with help of one or more agents like heat, pressure, humidity, catalyst. Particle boards depend entirely on the adhesive additive for the cohesiveness.

Types of Particle boards : 

Types of Particle boards Flake Board Chip Board Shaving Board

Manufacture of Particle Board : 

Manufacture of Particle Board Particleboard is manufactured by mixing wood particles or flakes together with a resin and forming the mix into a sheet. The raw material to be used for the particles is fed into a disc chipper with between four and sixteen radially arranged blades. The particles are first dried, after which any oversized or undersized particles are screened out.

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Resin: liquid form, is then sprayed through nozzles onto the particles. There are several types of resins that are commonly used. Urea formaldehyde resin is the cheapest and easiest to use. It is used for most non-water resistant boards. Melamine formaldehyde resin is significantly more expensive, as it is moisture resistant.

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Phenol formaldehyde is also fairly expensive. It is dark colored and highly durable. These resins are sometimes mixed with other additives before being applied to the particles, In order to make the final product waterproof, fireproof, insect proof, or to give it some other quality. Once the resin has been mixed with the particles, the liquid mixture is made into a sheet. Weighing device notes the weight of flakes, and they are distributed into position by rotating rakes.

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In graded density particleboard, the flakes are spread by an air jet which throws finer particles further than coarse ones. Two such jets, reversed, allow the particles to build up from fine to coarse and back to fine. Melamine formaldehyde resin board Phenol formaldehyde applied board

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The sheets formed are then cold-compressed to reduce their thickness and make them easier to transport. Later, they are compressed again, under pressures between two and three megapascals and temperatures between 140 °C and 220 °C. This process sets and hardens the glue.

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All aspects of this entire process must be carefully controlled to ensure the correct size, density and consistency of the board. The boards are then cooled, trimmed and sanded. They can then be sold untreated, covered in a wood veneer or laminated with paper.

Flaking Machine : 

Flaking Machine

Properties Of Particle Board : 

Properties Of Particle Board

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Moisture Properties: Conditions likely to change the moisture content above or below the 8-12% range normally applying at dispatch from the factory, may give rise to problems. Moisture content will normally be in the range 10-12% when used in buildings intended for human occupancy. Measurement of moisture content may be achieved by weighing and drying or by using an electric moisture meter.

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Thermal Properties: The Thermal Conductivity of Particleboard varies slightly according to thickness with the usual range being 0.10 to 0.14 W/mK. Within the normal range of temperature variation, Particleboard is dimensionally stable and its strength properties are unaffected.

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Acoustic Properties: Particleboard should achieve a sound transmission loss of 25 db. Typical Property Values for Standard particleboard

Comparison of solid wood Vs Particle board : 

Comparison of solid wood Vs Particle board Solid wood is prone to warping and splitting with changes in humidity, whereas particleboard is not. Solid wood has structural advantages over particleboard. Solid wood is more durable than particleboard. Damage to solid wood can be repaired by removing and replacing damaged material then refinishing using known wood treatments that can be matched. particleboard is typically faced with by a non-wood veneer, it may be impossible to match the original finish.

Uses Of Particle board : 

Uses Of Particle board Interior fitting in buildings Furniture Ceilings Cabinets

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Biodeterioration Particleboard is susceptible to attack from wood destroying fungi and termites. However moisture contents of over 18% must be maintained before either form of biodeterioration can occur. Post treatment with brush-on preservatives will protect against the growth of surface mould which can disfigure the surface appearance.

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Method of preserving particle board against decay and mould: The invention also concerns a binder composition, which contains a polymer resin as its adhesive component and a complexing agent, particularly an aminotetracarboxylic acid or a salt, by approx. 1-30 wt.-% as the preservative of the wood material, and a method of producing binder composition.

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Reference: Forest Utilization By TRIBHAWAN METHA http://www.wisegeek.com/how-is-particle-board-made.htm http://en.wikipedia.org/wiki/Particle_board

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Thank You