Of a thickness exceeding 9 mm

44.11 Fibreboard of wood or other ligneous materials, whether or not bonded with resins or other organic substances. - Medium density fibreboard (MDF) : - - Of a thickness not exceeding 5 mm 4411.13 - - Of a thickness exceeding 5 mm but not exceeding 9 mm 441 1.14 - - Of a thickness exceeding 9 mm - Other : 441 1.92 - - Of a density exceeding 0.8 g/cm3 441 1.93 - - Of a density exceeding 0.5 g/cm3but not exceeding 0.8 g/cm3 441 1.94 - - Of a density not exceeding 0.5 g/cm3 44 11.12 Fibreboard is most often manufactured fiom wood chips which have been mechanically defibred (defibrated or steam exploded or fiom other (obtained e.g., from agasse or bamboo). The fibres making up the microscopic examination. They are bonded together in the board adhesive properties, generally deriving fiom their lignin organic bondm substances may be used to agglomerate the may also be a ded during or after manufacture of the board to give an extra pro erty, e.g., impermeabili to water or resistance to rot, insect attack, fire or the spread of flame. ibreboard may consist o a single sheet or of several sheets bonded together. fi F The categories of fibreboard of this heading can be distinguished according to their production process and they include : (A) Fibreboard obtained by the '(dry production process" This group includes, in articular, medium density fibreboard (MDF), which is manufactured in a process in which a ditional thermosetting resins are added to the dried wood fibres in order to assist the bonding rocess in the press. The densi generally ranges from 0.45 g/cm3 to 1 g/cm3. In the unwor ed state it has two smooth sur"(aces. It can be used in many different applications such as furniture, interior decoration and in building. B r: Medium densi fibreboard of a density exceeding 0.8 g/cm3is sometimes also referred to by the trade a s "hig density fibreboard (HDF)". (B) Fibreboard obtained by the "wet production process'' This group includes the following types of fibreboard : (1) Hardboard, which is manufactured in a wet production process in which the wood fibres in suspension in water are compressed in the form of a mat under high temperature and high pressure on a metallic mesh. In the unworked state this type of fibreboard has one smooth and one rough surface with a mesh attern. However, it can sometimes also have two smooth surfaces obtained by special s d a c e treatment or a special production process It generally has a density exceeding 0.8 g/cm3. Hardboard is manly used for furmture, & the automotive industries, for doorskins and for packaging, especially fruit and vegetable packaging. (2) Mediumboard, which is manufactured in a way similar to the one for hardboard but at a lower pressure. It generally has a density exceeding 0.35 glcm3 but not exceeding 0.8 g/cm3. The main applicahon is in furniture production and for interior or exterior walls. (3) Softboard. This fibreboard is not compressed as the other es of fibreboard obtained b the wet roduction process. It generally has a densi of 0.3 g/cm3 or less. These boar s are use mainly for thermal or sound insulation in uilding. Special types of insulating board are used as sheathing or sarking materials. '% 9 a dY The products of this headin remain classified herein whether or not they have been worked to form the shapes provided or in respect of the goods of heading 44.09, curved, corrugated, erforated, cut or formed to shapes other than square or rectan lar and whether or not they Eave been worked at the surface, the edge or the end, or coate or covered (e.g., with textile fabric, plastics, paint, paper or metal) or submitted to any other operation, provided these operations do not thereby give such products the essential character of articles of other headings. f f' The heading does not cover : (a) Particle board whether or not laminated with one or several fibreboards (heading 44.10). (b) Laminated wood with a core consisting of fibreboard (heading 44.12). (c) Cellular wood panels of which both faces are fibreboard (heading 44.18). (d) Paperboard, such as multiplex paperboard, i(presspan k) and strawboard, which can generally be distinguished from fibreboard by their layer structure made apparent on cleaving (Chapter 48). (e) Fibreboard panels clearly identifiable as parts of fimiture (generally Chapter 94).