Continuous adjustable and controllable water vapor sealing type double screw rod extruder

Abstract

The invention relates to a continuous adjustable and controllable water vapor sealing type double screw rod extruder, which is mainly used for polyvinyl alcohol fiber melt spinning by using water as plasticizers and comprises double screw rods (1), a jacket (2), a sealing type pressure control valve (3), a cooling sleeve (4), a metering feeding device (5), a screw rod temperature control device (6), a driving transmission system (7), a motor (8) and the like. The continuous adjustable and controllable water vapor sealing type double screw rod extruder is characterized in that 1, the double screw rods at least consist of a metering feeding device (4), a small-lead-stroke positive threaded element (9), an engaging block (10) and an opposite threaded element (11), and the swelling and melting continuity is realized; 2, the threaded elements of the double screw rods at least consist of a first threaded element (12), a second threaded element (13) and a third threaded element (14), and the water vapor is sealed by utilizing the pressure difference; and 3, through the arrangement of the sealed pressure control valve (3), the pressure can be regulated when the process is changed, and the water vapor sealing is realized.

Description

technical field [0001] The invention relates to a twin-screw extruder, in particular to a water vapor-sealed twin-screw that can be used for polyvinyl alcohol melt spinning for swelling, melting, and extrusion continuous control. Background technique [0002] Polyvinyl alcohol (PVA) is a polymer with excellent performance and wide application. Traditional PVA fibers can be produced by wet spinning and gel spinning, but these methods are relatively complicated and pollute the environment. Since polyvinyl alcohol contains a large number of hydroxyl groups in its molecular structure, a large number of hydrogen bonds will be formed between macromolecules, resulting in its melting point being close to its decomposition temperature. In theory, it is difficult to use an economical, efficient, and low-environmental-pollution melt-spinning method. At present, researchers use modifier water to destroy the hydrogen bonds between polyvinyl alcohol molecules, limit its crystallization, ...

AI Technical Summary

Problems solved by technology

The above-mentioned method for producing polyvinyl alcohol fiber by melt spinning handles the swelling process of the spinning raw material and the melt extrusion process separately, which is a discontinuous production method, and the production efficiency will be greatly reduced in the large-scale industrial production process. It will increase the consumption of manpower and material resources, and the production cost will increase accordingly.

In addition, in the melt spinning process of polyvinyl alcohol, due to the large amount of water in the melt, a large amount of water vapor will be evaporated under high pressure in the single-screw or twin-screw high-temperature melting zone, and the water vapor will Back from the feed port, the ratio of polyvinyl alcohol to water cannot be controlled within a certain range, the melt viscosity cannot be maintained, and high-performance polyvinyl alcohol fibers cannot be obtained, and spinning cannot even proceed smoothly. Further, in When the spinning process needs to be adjusted, the pressure inside the screw cannot be controlled within the conditions required for sealing

The above-mentioned patents all use ordinary screw extruders for processing, and cannot solve these problems faced by polyvinyl alcohol in the melt spinning process

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