The blockboard is commonly known as a large core board. It is a board made of wood strips in the core board or glued into a plate or square without glue, and one or two layers of wood veneers are glued on both surfaces.
Different crafts, different quality, a piece of blockboard production requires more than 30 processes. After the logs are processed into wooden boards, they are first dried. Then the boards are placed in a natural state to balance the dryness. The water content is finally controlled at about 72, and then sawn into wooden strips, spliced ​​into core sheets, glued, laminated, The hot pressing process is made into a blockboard. The core board processing technology of blockboard is divided into two types: machine and hand. Hand-made is to use the artificial code to put the wooden strips, the gap between the wooden strips is large, and the stitching gap is not uniform. The machine core board is subjected to lateral extrusion, the stitching gap is extremely small, and the stitching is flat. Therefore, the machine board is compact and long-term use and is not easily deformed. Different materials, different quality of wood board according to the quality of the material and the quality of the surface material is divided into "excellent products", first-class products and "qualified products." Some companies also grade the board grades A, double A and Three A-level, but this is just a corporate behavior, which is inconsistent with national standards. This standard has not been allowed on the market. There are many kinds of wood board core boards, such as poplar, elm, pine, paulownia, etc. Among them, poplar wood and pressed wood are better, the texture is dense, the wood is not soft and hard, the nail holding power is strong, and it is not easy to be deformed. The texture of the bubble phase is light and soft, the water absorption is large, the nail holding power is poor, and it is not easy to be baked. Dry, made into a plate in the process of use, when the water evaporates, the plate is easy to dry and deform. Hard wood is hard, not easy to press, the splicing structure is not good, the nail holding power is poor, and the deformation coefficient is large. The veneer can be made according to the tree species. Divided into Liu press, wood, cedar, etc. The surface of the fine wooden slab plate is smooth and smooth, not easy to warp and deform, and can be divided into one light and two light according to the surface sanding. Intuitively judge the national standard in the blockboard The quality standard stipulates more than 7 indicators, including thickness dimension, web size, warpage, physical and mechanical properties, material defects, processing defects, moisture content, bonding strength, board surface defects, formaldehyde release limits, etc. For these quality indicators Most of the rigorous testing needs to be done in the laboratory, but consumers can judge the quality of the board by some simple and intuitive methods.
Appearance: The appearance should be flat and full of defects, and the logo should be complete. The quality of the blockboard of mercury should be smooth and free of defects, such as no dead knots, excavation, leaking glue, etc. The thickness of the middle plate is uniform, no overlap, separation of seams, and the splicing of the core plates is tight, especially the blockboard There must be no cracking at the end. The corners should be straight and the diagonal error should not exceed 6mm. The whole package of fine wood boards should be completely fitted between the boards. Tactile sensation: Touch the surface of the blockboard by hand. The quality blockboard should be dry and smooth. Intrinsic quality: With good appearance quality, we should pay more attention to internal quality. Otherwise, the appearance looks like a flat and clean blockboard. Once sawn, it may be dark, dead wood, or a lot of big gaps. Intrinsic quality must first check whether the core board is dense, whether there are obvious gaps and decaying wood strips, and there may be eggs in the decaying wood strips. In the future, it is easy to see the insects and then see if there is any glue or greasy putty around. This phenomenon is generally used to compensate for internal cracks or voids. Since the meat quality of the blockboard cannot be understood from the appearance, consumers can judge it by simple methods. Look at the blockboard against the light. If it is white, the density of the bar is not enough: when you pick it up, you can hear the sound, and there is a humming sound to indicate that the glue strength is not good: pick up one end of the blockboard, lick it, quality joinery The board should have a sense of overallity and weight. Of course, this kind of heavy induction is a good one when the hand feels dry, otherwise the dryness is not enough. Then hit the surface of the board with a hard object and listen to the sound. If there is a change in the sound, there is a hole inside the board. These phenomena will weaken the overall bearing capacity of the board, and the long-term stress will easily cause the sheet to be deformed, affecting the outside and the use effect. In addition, consumers should avoid a few misunderstandings when purchasing plates: "The sleek and smooth plates must be good." This is not true. In fact, the more such a plate consumer, the more careful. Trimming is produced by machine saws. Good plates generally do not need to be “reprocessed†and often have a lot of donkeys. However, the quality of the plate has a hollow, black heart, so the processor will "carefully dress", put a "good-looking" wood on the cut edge, and smooth and smooth the month to confuse the consumer, so can not Use this as a standard to measure good or bad. The saying that "the heavier the plate is, the better" is not necessarily correct. The plate is not like solid wood furniture, the heavier and stronger. The insider buys the plate to see the degree of drying, and the second looks at the stitching. Plates with good dryness are relatively light and do not crack and are flat. For the consumption of laymen, the safest way is to buy some well-known brands of plates in the reliable building materials market. Can not ignore the environmental performance. Third, the blockboard is generally used in the slab splicing of the core board and the panel is bonded with the urea-formaldehyde glue, and the formaldehyde we are currently paying attention is emitted from the urea-formaldehyde glue. Therefore, an important difference between environmentally friendly blockboards and inferior blockboards is the quality of the glue. If the blockboard is made of environmentally friendly glue, the storage place and the board are only woody, and the smell of formaldehyde is not smelling. If the blockboard emits a pungent odor, the formaldehyde emission of the furfural glue used is high and cannot be used for interior decoration.
Experts remind consumers that the so-called "special grade" blockboard in the market is only the product quality standard of the manufacturer and cannot be used as a standard for environmental protection. <Limited Quantity of Hazardous Substances in Interior Decoration Materials> One of the ten standards GBl8580-2001 stipulates that the blockboard is determined by the dryer method. The formaldehyde emission value is less than or equal to 1.5mg/L, which is El grade, and can be directly used indoors; Less than or equal to 5.Omg / L is E2 grade, must be treated after the finish can be used indoors. Consumers should identify the above signs when purchasing blockboard, and if necessary, check the product inspection certificate to confirm that it is environmentally friendly sheet that is harmless to the human body.
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