Method for spinning thermotropic liquid crystalline polyarylate by using reducing screw melt extruder

A melt extrusion, variable diameter screw technology, applied in the direction of feeding the solution to the spinneret, textile and papermaking, complete sets of equipment for the production of artificial threads, etc. The uniformity of the fiber, the quality of the fiber forming, and the instability of the melt advance, to achieve the effect of helping to remove moisture, avoid moisture absorption, and save factory space.

Inactive Publication Date: 2012-10-17
DONGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, the conical screw extruder in the previous patent involves either a screw that is conical from feeding to extrusion, or a parallel structure at the rear of the screw (patent number: 201020548822.0), and these extruders Mainly used in rubber or plastic fields, not for spinning
The tapered structure from the feed to the extrusion will cause the melt to advance unstable, which will seriously affect the quality of the raw silk; and the use of a parallel structure at the rear end of the screw can make the melt extrusion uniform, but from the diagram It can be seen that two-thirds of the entire screw section is still a conical feeding and melting section, and only one-third is a parallel extrusion section. This structure is beneficial to plastic extrusion molding.
However, for the spinning pellets or powder, the pre-crystallization and vacuum exhaust drying of the feed must be very uniform, because the pre-crystallization of the spinning raw material and the unstable fluctuation of the moisture content will inevitably affect the melt in the subsequent compression and metering section. Stability, which affects the uniformity of the spinneret drawing and the quality of fiber formation
It is very difficult for the existing technology to ensure that the drying and pre-crystallization of the raw materials are carried out evenly during the extrusion process and at the same time ensure that the moisture in the raw materials can be fully removed. Meeting Plastic Extrusion and Spinning Requirements

Method used

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  • Method for spinning thermotropic liquid crystalline polyarylate by using reducing screw melt extruder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Using a thermotropic liquid crystal polyarylate spinning method with a variable-diameter screw melt extruder, the TLCP pellets with a melting point of 280 ° C and a moisture content of 70 ppm are melt-extruded, and the outer cone angle of the conical cylinder is The range is 20 degrees, the pre-melting exhaust zone accounts for 15% of the entire screw, the pre-crystallization drying zone accounts for 40% of the total screw length, and the melting zone accounts for 10% of the total screw length; the temperature of the feed pre-crystallization drying is controlled at 130~150°C, the temperature of pre-melting air extraction is controlled at 270°C; the diameter ratio of the cylinder in the feed pre-crystallization drying zone to the cylinder in the melting zone is 3:1; the conical cylinder in the pre-melting exhaust zone is installed There are 16 exhaust ports, the aperture of the exhaust port is 12mm, and the exhaust port is connected to a vacuum device, and the moisture co...

Embodiment 2

[0023] Using a thermotropic liquid crystal polyarylate spinning method with a variable-diameter screw melt extruder, the TLCP pellets with a melting point of 290°C and a moisture content of 50ppm are melt-extruded, and the outer cone angle of the conical cylinder is The range is 10 degrees, the pre-melting exhaust area accounts for 13% of the entire screw, the pre-crystallization drying area accounts for 35% of the total screw length, and the melting area accounts for 15% of the total screw length. The temperature of the feed pre-crystallization drying is controlled at 140~160°C, the temperature of pre-melting air extraction is controlled at 285±2°C; the diameter ratio of the cylinder in the feed pre-crystallization drying zone to the cylinder in the melting zone is 2:1; the conical cylinder in the pre-melting exhaust zone The body is equipped with 8 exhaust ports, and the aperture of the exhaust port is 6mm. The water content of the TLCP obtained at the mouth of the melt extru...

Embodiment 3

[0025] Using a thermotropic liquid crystal polyarylate spinning method using a variable-diameter screw melt extruder, the TLCP pellets with a melting point of 305 ° C and a moisture content of 50 ppm are melt-extruded, and the outer cone angle of the conical cylinder is The range is 3 degrees, the pre-melting exhaust zone accounts for 10% of the entire screw, the pre-crystallization drying zone accounts for 30% of the total screw length, and the melting zone accounts for 13% of the total screw length. The temperature of the feed pre-crystallization drying is controlled at 150±5°C, the temperature of pre-melting air extraction is controlled at 300°C; the diameter ratio of the cylinder in the feed pre-crystallization drying zone to the cylinder in the melting zone is 1.5:1; the conical cylinder in the pre-melting exhaust zone is installed There are 4 exhaust ports, the aperture of the exhaust port is 8mm, and the exhaust port is connected to a vacuum device, and the moisture cont...

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Abstract

The invention provides a method for spinning thermotropic liquid crystalline polyarylate by using a reducing screw melt extruder, and particularly relates to a method for spinning the thermotropic liquid crystalline polyarylate by using an integrated reducing screw melt extruder. According to the method for spinning the thermotropic liquid crystalline polyarylate by using the reducing screw melt extruder, the extruder is divided into a feed pre-crystallization drying area, a pre-melting air discharging area, a melting area and a compression metering area from front to back; barrels of the feed pre-crystallization drying area, the melting area and the compression metering area are cylindrical; the pre-melting air discharging area is conical; and the diameter of the barrel of the melting area is the same as that of the barrel of the compression metering area but is smaller than that of the feed pre-crystallization drying area. The temperature required by feed pre-crystallization drying is controlled to be 130 to 180 DEG C, and the temperature required by pre-melting air exhaust is controlled to be 3 to 10 DEG C less than the temperature required by melting raw materials. By the method, the raw materials are dried in the extrusion process, the pre-crystallization uniformity is high, the water in the raw materials can be fully removed, and large drying equipment is not needed.

Description

technical field [0001] The invention relates to a thermotropic liquid crystal polyarylate spinning method of a variable-diameter screw melting extruder. Background technique [0002] During the processing of thermotropic liquid crystal polyarylate (TLCP), the presence of moisture will seriously affect the mechanical properties of the material, so the raw materials need to be dried before the screw extruder. Due to the characteristics of molecular structure, the moisture content of thermotropic liquid crystal polyarylate pellets or powder itself is not high, but if the moisture is not removed, it will seriously affect the spinning process; if conventional drying equipment is used, it will take up a lot of space and cause Waste of energy, space, manpower and other resources. [0003] In order to remove the moisture in the raw material, relevant researchers have designed a conical screw extruder. The conical screw extruder can effectively avoid the installation of drying devi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01D1/06D01D1/09D01D13/02B29C47/60B29C47/76B29C48/525B29C48/76
CPCB29C47/6012B29C48/525
Inventor 王依民倪建华朱卫彪邹黎明王燕萍甘海啸
Owner DONGHUA UNIV
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