Oriented strand board (OSB) is a new high-tech material used in timber frame house building, furniture manufacturing, and packaging.
OSB boards are made by gluing large-sized (3-8 cm) thin shavings, and in the upper and lower layers the direction of the fibers is located longitudinally, and in the middle layer - transverse to the length of the board. In terms of physical properties, OSB boards are similar to softwood plywood, but they are much cheaper to manufacture due to low quality requirements for wood raw materials. Due to the lower cost with the same consumer qualities, oriented strand boards are gradually replacing plywood in many traditional fields of application.
Oriented strand board is a dense compressed three-layer wood board made of large oriented coniferous chips. It is a substitute for plywood and chipboard.
The appearance of the oriented strand board clearly explains its name. The slab can be easily distinguished by elongated chips.
Oriented strand board consists of three layers. In the outer (upper and lower) layers, the chips are located longitudinally, and in the inner layer transversely. Each layer is glued with waterproof resins and pressed under high pressure and temperature.
As a result of this technological feature, OSB boards acquire water resistance, elasticity and resistance to stretching and construction loads.
Oriented particle board (OSB) is produced by hot pressing wood chips mixed with a binder.
OSB production technology was first applied on an industrial scale in the United States in the early 1990s.
According to this production technology, the logs are first sorted, then special processing is carried out and fumigated. Then the logs are planed along the fibers in order to maximize the strength of the wood structure to obtain chips. The average length of chips is 80 mm, and the width varies depending on the part of the trunk.
Thus, OSB boards are made only of particles with a size of 75-150 mm in length, 10-25 mm in width and 0.5-0.75 mm in thickness. Smaller fractions (20-30% of the total yield) are screened out and either burned or used in the production of chipboard and MDF, for the production of which small-sized and non-commercial wood of coniferous and deciduous species is used. This ensures that the slab structure is uniform.
Next, the resulting chips are dried and impregnated with waterproof resins with the addition of synthetic wax. The use of wax ensures high quality products. Then the chips are laid on a conveyor belt in two directions, creating a so-called carpet. In the outer layers of the board, the chips will be oriented along the length, and in the inner layers - across. After that, the carpet is pressed on a multi-layer press at high temperatures and pressures. Finally, the OSB sheet is cut into standard formats and sanded.
Increased mechanical properties in comparison with conventional chipboard are achieved precisely due to the creation of the effect of different orientations of chips in the outer and inner layers of OSB boards.
The tensile strength of such plates with a density of 650-720 kg / cu. m with static bending is 40-50 MPa in the longitudinal direction and 20-25 MPa in the transverse direction. For comparison: general purpose birch plywood has a static bending strength of 55-60 MPa.
By changing the design, for example, the number and thickness of layers with a certain orientation of wood particles in them, the type of binder used and its consumption, the size of wood particles, it is possible to impart certain properties to OSB boards in accordance with their purpose.
In addition to sufficiently high strength properties, this material has high moisture resistance and structure homogeneity, excluding such defects as delamination, warping, internal voids, cracks, knots falling out. OSB boards are quite well processed and significantly better than chipboard, hold fasteners (nails and screws).
Mainly, coniferous wood of medium and low quality is used as raw material for the production of boards. In summer - 100% pine. In winter - 60% - pine, 10% - spruce, 10% - larch, with the addition of deciduous wood (birch) in an amount of up to 20%.
For production, small-sized wood with a diameter of 70-100 mm can be used, which cannot be processed in sawmilling or plywood production. At the same time, which is very important, wood waste is not used. Due to the low quality requirements for raw materials, the cost of raw materials and materials is significantly reduced.
One of the main features of OSB board production is the elimination of small chips and crushed product. As a result, a reduction in the amount of adhesive used in OSB boards (2-3%) is achieved in comparison with other wood boards.
OSB production technology is constantly being improved. Phenol-formaldehyde, urea-formaldehyde resins of the E1 class, as well as isocyanate esters, which are used to increase the stability of the properties of boards and increase environmental safety, assessed by the emission of free formaldehyde into the environment, are widely used as binders.
In the West, OSB (Oriented Strand Board) - oriented strand board is ranked among the most promising universal building materials of the millennium due to a whole range of consumer advantages of this product in comparison with traditional woodworking products, provided by the use of new modern technology of wood modification.
OSB board was developed in 1980 in the USA as a substitute for chipboard based on the use of the latest research and development achievements in wood composite technology, where it received the most widespread use.
This production is also actively developing in Europe, and more recently in Asia and Oceania. Progressive technology provides high line productivity and product quality used in the furniture industry, construction, packaging industry, combined with the ability to use low-quality wood and wood waste as raw materials.
Currently, in the world practice, the production of boards with new molding methods is widespread, replacing the existing production of boards. These include the production of Oriented Structure Particleboard (OSB).
The creation of OSB was a continuation of the development of waffle plates in the late 1970s. OSB differs from them by long wood shavings, which are oriented mutually perpendicular in layers. The debut of OSB boards took place in the North American market in 1978. and due to their unique properties, OSB boards were quickly adopted.
At the beginning of the 80s, the rapid development of OSB board production began. And by 2000, the production of OSB boards in the United States was almost equal in volume to the production of plywood.
In many areas of North America, OSB has actually replaced other material groups in new home construction. Today, all building codes in the US and Canada recognize OSB panels as an alternative to plywood. In 1996. The OSB product has been adopted by the Chicago Stock Exchange for futures and options trading.
Currently, the consumption and production of OSB boards is developing intensively, both in North America and in Europe. In other markets, their consumption is relatively low, but there is a constant upward trend.
Currently, in the world, oriented strand board has a very wide scope, and is primarily widely used in both residential and industrial construction, as well as used in the manufacture of furniture.
By industry, the main consumers of OSB boards are: construction industry; production of containers and packaging; furniture industry. OSB is a material that is gradually beginning to occupy the consumer niche traditionally occupied by plywood products, as well as a number of areas where chipboard has traditionally been used.
Currently OSB boards are used in the following areas:
- cladding of external and internal walls, attics;
- production of subfloors, bases for carpets and linoleum coverings;
- production of reusable removable formwork structures;
- sheathing of roofs (instead of the usual lathing of unedged boards), in this case, an ideal base for a soft roof (bituminous shingles) is obtained;
- production of wall panels (OSB plus insulation plus OSB)
- manufacturing (using LVL material) long-span beams (I-Joist or I-Beam);
- construction of temporary barriers and demountable structures;
- use for decorative purposes and interior decoration, due to the original surface texture;
- in construction as beams, moldings, etc.
- production of panel board elements of cabinet furniture,
- manufacture of walls of cabinets and pedestals, drawers, shelves.
- bases for upholstered furniture, etc.
Container and packaging production
- manufacturing of shipping containers, an aid in the formation of packaging;
- as substitutes for sawn timber.