A bookcase, or bookshelf, is a piece of furniture with horizontal shelves, often in a cabinet, used to store books or other printed materials. Bookcases are used in private homes, public and university libraries, offices and bookstores. Bookcases range from small, low models the height of a table to high models reaching up to ceiling height. Shelves may be fixed or adjustable to different positions in the case. In rooms entirely devoted to the storage of books, such as libraries, they may be permanently fixed to the walls and/or floor.
A bookcase may be fitted with glass doors that can be closed to protect the books from dust or moisture. Bookcase doors are almost always glazed with glass, so as to allow the spines of the books to be read. Especially valuable rare books may be kept in locked cases with wooden or glazed doors. A small bookshelf may also stand on some other piece of furniture such as a desk or chest. Larger books are more likely to be kept in horizontal piles and very large books flat on wide shelves or on coffee tables.
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The medium density fiberboard or high density fiberboard of 8 mm or 9 mm thickness is used as the substrate; the melamine impregnated paper made of Al2O3 wearable surface layer is generally coated with a thickness of 0.2 mm or 0.8 mm; the thickness of the bottom layer is 0. 2mm or 0.3mm melamine impregnated balance paper, the composite sheet formed is called composite laminate flooring.
The main process flow is as follows: surface layer, core layer, bottom layer → composite billet → hot pressing → cooling → feeding → detecting metal inclusions → specification cutting → longitudinal section → cross section → opening groove → inspection → finished product → packaging storage
The width of the composite laminate flooring is usually 1 2 80mm × 1 95mm × 8mm, and the four sides have the tongue and mouth, which is very convenient to install and use. The composite reinforced floor has excellent physical and mechanical properties. Take the “Huili†brand floor produced by Shanghai Huili Flooring Co., Ltd. as an example. The physical and mechanical properties are shown in Table 1.
Table 1 Physico-mechanical performance indicators of Huili floor test project indicators test project indicators
Density, g/cm30. 89
Specifications, mm 1 3 70× 1 90× 8
Static bending strength, MPa 3 7. 4
Modulus of elasticity, MPa 683 2
Internal bonding strength, MPa 1. 75
Surface bonding strength, MPa 2 . 1 3
Water absorption thickness expansion, %5.9 moisture content, %3. 8
Formaldehyde content, mg/ 1 0 0g 1 6
Wearable surface, turn 90 0 0
Surface scratches, N 5. 0 surface resistant to cigarette burning without black spots, cracks, bubbling
Surface impact resistance is slight
Price, yuan / m2 189
The production units based on composite laminate flooring belong to the departments of building materials, light industry, forestry and construction, and about 1 / 5 of the medium-density fiberboard production lines built and rebuilt in China are processed by composite laminate flooring. Statistics have certain difficulties. The composite laminate flooring manufacturers generally have more than 40 foreign composite laminate flooring products registered in China, from Germany, France, Austria, Norway, Belgium, Sweden, Spain, Italy and other countries. Among them, German and Austrian products are well-known, and their prices are high, such as the price of German laminate flooring (specification 1 2 85mm × 1 90mm × 8mm): iconic ultra-luxury 3 2 8 yuan / m2, iconic luxury 2 68 yuan /m2, love home 1 88 ~ 2 0 8 yuan / m2, Youqiang 1 77 yuan / m2, De Laibao brand 2 99 yuan / m2.
2 Requirements for constituent materials
2.1 Performance requirements for the substrate
To meet the physical and mechanical properties of composite laminate flooring, the physical and chemical properties of the substrate are extremely important. Generally, medium density fiberboard should have:
Internal bonding strength ≥ 1. 0MPa
Static bending strength ≥ 40 . 0MPa
Elastic modulus ≥ 40 0 ​​0MPa
Water absorption thickness expansion rate ≤ 10%
Formaldehyde emission ≤ 9mg / 1 0 0 g
Moisture content 4% to 10%
Thickness deviation ± 0 . 1 5mm
Length and width dimensions deviation ± 2.0 mm/m
Edge non-straightness ≤ 1. 0mm/m
Sand content ≤ 0 . 0 5%
Toluene adsorption ≤ 1 50mm
Appearance requires no oil, gelatin, indentation, partial softness, layered bubbling, charring phenomenon
Analysis of the status quo and composition of composite laminate flooring in China (1)
1 Introduction to composite laminate flooring