| 摘要 |
PURPOSE: Provided is a method for constructing an elastic layer packing material by the preparation process of a two-pack type polyurethane chip to obtain a bottom material having excellent durability and elasticity. CONSTITUTION: The method comprises the steps of mixing 30-40 wt% of a triol with a molecular weight of 3,000-5,000, 25-35 wt% of a diol with a molecular weight of 2,000-3,000, and 20-30 wt% of an isocyanate at a thermostat reactor of 60-80 deg.C to react them for 3-5 hours to prepare a first type pack; mixing 6-9 wt% of a triol with a molecular weight of 3,000-5,000, 30-40 wt% of a diol with a molecular weight of 2,000-3,000, a filer, a plasticizer, a colorant and other additives and dispersing the mixture with a velocity of 2,000 rpm for 3-5 hours to prepare a second type pack; weighing the first and second type packs and mixing them; injecting the mixture into a mold to prepare a sheet with a thickness of 20-30 nm; firstly curing the sheet at a room temperature, separating the cured one from the mold, and secondly curing it at 70 deg.C for 4-6 hours with 55-66 shore A; pulverizing the cured sheet to prepare a polyurethane elastic chip; mixing the chip with a binder and an additive and coating it onto a packing surface with a uniform thickness; stamping the coating with a thermostat roller for 5-6 times; and curing it for 32 hours in spring or fall, 24 hours in summer and 48 hours in winter.
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