The difference between hardboard and MDF!
hardboard is a kind of product which is made from plant fibers and is separated, shaped, hot-pressed (or dried) by fibers. There are many classification methods for hardboard , which can be classified according to raw materials, production methods, density, structure, use and appearance. hardboard can be divided into three types according to its density: hard hardboard with density above 0.8 cm3; semi-hard hardboard with density of 0.4 cm3-0.89 / cm3 (medium density hardboard with density of 0.5 em3-0.889 / cm3); soft hardboard with density below 0.4 cm3.
Hard hardboard has high strength and is mostly used in the decoration of vehicles, ships and aircraft, as well as in the construction industry and furniture manufacturing industry. Flexible hardboard has the properties of insulation, heat insulation, sound absorption and so on. It is mainly used in the construction sector, such as the wall panels and ceiling of radio studios, cinemas, etc. Semi-rigid hardboard is an excellent material for furniture manufacturing and interior decoration of buildings.
There are many methods to produce hardboard , which can be divided into wet and dry methods according to the forming medium. Wet process is the main manufacturing process at present. Its characteristic is that water is used as the medium of fiber transportation and slab forming. The moisture content of the wet slab after forming is 60%-70%. The advantage of wet method is that it does not need adhesives. Sometimes a small amount of adhesives is used to further improve product quality.
Dry process is characterized by the use of air as the medium for fibre transportation and slab forming. After forming, the moisture content of slab is only 5%-10%. Due to the lack of moisture in the slab, due to the effect of pressure and temperature during hot pressing, the bonding force between fibers and fibers can not be formed sufficiently. Therefore, adhesive is needed to improve the strength and water resistance of the product.
The production of hardboard in the world began in the early 20th century. During the half century, hardboard developed rapidly and became a complete and independent industrial system. China’s hardboard production began in 1958, after 29 years, from scratch, from small to large, from soil to ocean, has developed to the present level of a complete industrial production system. According to 1979 forest products: [Industry Design Institute statistics, there are more than 340 hardboard factories and car inquiries in 28 provinces and cities in China, and these T factories account for 67% of the equipment made in China. The annual output was 180,000 m3 in 1975, 56.8 m3 in 1981 and 800,000-900,000 m3 in 1985.
Medium Density hardboard (MDF) is a kind of hardboard with density of 0.5_em3~O.889/em3 produced by dry or wet process. It is suitable for manufacturing furniture, building, vehicle and ship, electrical equipment and musical instrument box.
Medium density hardboard requires less raw materials than other types of wood-based panels, which opens up a new way for the development of wood comprehensive utilization. The production process of density hardboard in dry process is basically the same as that of rigid hardboard in dry process. In sizing process, medium density hardboard has low density, large L gap, and is produced by dry method. Therefore, the strength and water resistance of the hardboard can not be achieved by the self-binding force of the fibers, which requires the addition of waterproof agents and adhesives, and the amount of application is much higher than that of dry hard hardboard . Waterproofing agent is mainly liquid paraffin, which is applied after wood chips cooking, and the dosage is O.3%-1%. Adhesive depends on the use of the product. Urea-formaldehyde resin is often used in indoor products. It is applied after fiber separation, and the sizing amount is 8%-12%.
Medium density hardboard (MDF) was first developed and put into production in the United States in the 1960s, and developed rapidly in more than 30 years. According to statistics, in 1982, 34 factories in 18 countries have adopted dry process to produce MDF, which accounts for 200/,~30% of the world’s hardboard output. Fuzhou, China, introduced a set of dry density hardboard equipment from the United States in 1981. In 1980, Zhuzhou Dry Process hardboard Plant was transformed into a medium density hardboard plant and put into operation at the end of 1982. In 1986, the dry process density hardboard equipment imported from Sweden was put into operation in Nancha of China.如无特殊说明，文章均为本站原创，转载请注明出处。If there are no special instructions, the articles are original, if you want to use or reproduce, please indicate the original source www.plywoodinspection.com,If you find that our articles infringe on your copyrights and interests, please email us at email@example.com in time and we will delete it at the first time.