Nitrogen protection microwave vacuum drying device and drying method for optical plastic raw materials

Abstract

The invention discloses a nitrogen protection microwave vacuum drying device and a drying method for optical plastic raw materials; the drying device is internally provided with a drying tank, a storage bin, a heater, a conveying fan, a terminal hopper and a plurality of groups of valve devices; an air inlet of the conveying fan, the drying tank and the terminal hopper are connected through an airduct; a feeding pipeline is connected between the storage bin and the drying tank; the drying tank is also connected with the terminal hopper through a discharging pipeline; the air outlet of the conveying fan is connected with the discharging pipeline through a pipeline serially connected with a three-way pneumatic ball valve; the heater is installed on the drying tank; a spiral stirrer and a temperature sensor are also provided in the drying tank; the drying tank is also respectively connected with a vacuum pump and a nitrogen membrane group; and the discharging pipeline is provided with afourth pneumatic butterfly valve and a counter-type photoelectric sensor. The nitrogen protection microwave vacuum drying device and the drying method for the optical plastic raw materials provided bythe invention can effectively prevent the optical plastics from being oxidized during the heating process, the heating speed is fast and uniform, and a closed-loop conveying system is adopted to prevent the dried raw materials from occuring the phenomenon of moisture reabsorption.

Description

technical field [0001] The invention belongs to the field of plastic processing equipment, in particular to a nitrogen-protected microwave vacuum drying device and drying method for optical plastic raw materials. Background technique [0002] Optical plastic (for example, PC PMMA transparent nylon) is a material commonly used in optical products. In order to improve the qualified rate of optical products, these optical plastics need to be dried to meet the requirements of the injection molding process of the optical materials before processing the molded products. At present, for the drying of optical plastics, the method of hot air drying is generally used to remove the moisture in the plastics. The moisture on the surface of the plastic is easy to remove by hot air drying, but it is extremely difficult to use hot air drying for the ionized water in the plastic. However, the ionized water in these plastics cannot meet the requirements of the material injection molding proc...

AI Technical Summary

Problems solved by technology

However, under the condition of high drying temperature, if these optical plastics are decomposed with the oxygen in the hot air, the optical plastics will be oxidized, and then the material properties of the optical materials themselves will be destroyed.

The method of lowering the drying temperature and prolonging the drying time greatly reduces the drying efficiency, and the long-term drying further increases the probability of the optical plastic being oxidized

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