Most low pressure laminate surfaces are impregnated with only one resin. Two paper granules and medium density fiberboard were used only to solve the problem of light transmission or to cover the roughness or porosity of the surface of the substrate, and a laminate was applied on both sides to prevent curling. Hardboard is only laminated on the smooth side. When the hardboard is lowered from the press, their bottom side is moisturized to prevent curling tendencies. The surface texture of the low pressure laminate, such as a high pressure laminate, is achieved by a reliable release paper. But it is very difficult to do from the operation. Usually the surface is achieved by the surface of the polishing plate used. The panel surface is the replica negative of the polishing plate used. Because the press usually has only one opening, the specially processed polishing plate on the surface is not a major expense.
The press is a single-port short cycle cycle press with a normal operating speed of 70-120 cycles/h. The pressure, press time and temperature vary with the particular paper and substrate used for the particle board and medium density fiberboard. (1964-2480kPa). For hard fiberboard, the pressure used is (2963-3962 kPa). The temperature of the hot plate is about 33. 3 ° C higher than the temperature required to cure the resin. The temperature required for the melamine impregnated paper for a fast cure time of 35 s is 140-150 ° C. This requires a hot plate temperature of 200210 ° C. Including loading and unloading time, the press cycle time is 70 times. The temperature used for urea-formaldehyde resin impregnated saturated paper is similar. The drying of the dry gum line takes about 14 seconds, and the wet glue line solidification time is about the same, but the temperature is lower. If only the glue line needs to be solidified, the cycle time may reach 120 times per hour. For the low-pressure laminate, the carrier of the press is a single-layer laminate composed of a base sheet and a top surface and a bottom decorative paper. The decorative paper on the bottom surface of the base sheet is a problem. Sometimes a paper is applied to the bottom surface of a plate by a wet glue line. Enzenberger describes a method in which the substrate plate is electrostatically charged to hold the paper through the charged static electricity. Since low pressure laminates include base sheets, they are more loose than high pressure laminates.
This makes them less convenient to transport to very far distances. Therefore they are generally produced close to furniture manufacturers.
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