JPS6155448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a processing method for continuously heating synthetic resin chips and supplying the same in a fixed amount when the synthetic resin chips are continuously dried or solid-phase polymerized under vacuum. .

When synthetic resin chips are continuously dried under vacuum or subjected to solid phase polymerization, a treatment method is required that allows precise quantitative feeding. Feeding devices such as rotary valves and table feeders can be used under normal pressure, but extremely high precision is required in the feeding method in product processes where quality unevenness must be suppressed as much as possible.

Due to the above circumstances, a screw feeder is used when higher precision is required, but under vacuum, especially under a high vacuum of around 1 Torr, there is a difference in the degree of vacuum between the supply and discharge sides of the screw feeder. , it is difficult to supply accurately and quantitatively.

In other words, when the degree of vacuum on the discharge side is lower than that on the supply side, more than the set discharge amount is discharged, and the balance with the discharge side system, such as a dryer or solid phase polymerization machine, is lost, and the discharge side system becomes unstable. As a result, it becomes impossible to obtain a satisfactory product or troubles such as blockage occur. In addition, if blockage occurs, it causes damage to the equipment, resulting in unnecessary expense in terms of process loss and repair costs.

Furthermore, when feeding to a system that requires heating, such as a dryer, it is preferable to preheat the screw feeder by installing an electric heat or heating medium jacket. In this case, the chips tend to get caught in the gap between the barrel and the screw blade (flight part), which causes the chips to fuse and become deformed, and the chips get so caught that the motor overloads and becomes inoperable. In particular, when the barrel is circular, the above-mentioned tendency is strong and there is a problem in that stable operation cannot be performed because the chips are caught between the barrel and the flight part over the entire circumference of the inner wall of the barrel.

In view of this situation, the inventors of the present invention have determined that when synthetic resin chips are continuously dried or solid-phase polymerized under vacuum and heat, the synthetic resin chips are continuously heated, transferred with good quantity, and melted as a supply means. We have completed a processing method that can supply a fixed amount of chips without causing any stuck chips.

That is, the present invention provides a processing method for continuously heating and quantitatively feeding synthetic resin chips from a hopper to a vacuum container via a horizontal uniaxial screw feeder, in which the hopper and the vacuum container are connected by a conduit tube. In addition to maintaining the internal pressure of both,
The barrel of the screw feeder is a U-shaped trough body, and the gap between the lower semicircular inner wall of the trough body and the screw blade is set to be less than the thickness of the synthetic resin chip, and the outer side of the trough body is This method of processing synthetic resin chips is characterized in that the synthetic resin chips are supplied to a vacuum container while being heated by a formed heating jacket.

Hereinafter, the present invention will be explained based on the drawings. 1st
The figure is a layout diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a schematic cross-sectional view of the screw feeder shown in the figure, and FIG. 3 is a cross-sectional view taken along line AA in FIG. In the figure,
Reference numeral 1 denotes a hopper for synthetic resin chips such as polyester or polyamide, and a heated vacuum container 2 for drying or solid phase polymerization is disposed below the hopper. 3 is a screw feeder provided between the hopper 1 and the vacuum container 2, the supply port 3a and the discharge port 1a of the hopper 1 and the discharge port 3b and the supply port 2a of the vacuum container 2 are interconnected, Chips in the hopper 1 are continuously supplied to the vacuum container 2 via the screw feeder 3. Screw feeder 3 is a trough-shaped body (hereinafter referred to as trough 4) with a U-shaped cross section and a circular lower half (hereinafter referred to as trough 4).The trough is published on May 10, 1960, published by Maruzen Co., Ltd., Chemical Engineering Handbook Revised Third Edition (see page 844) and a rotating shaft 6 having a screw blade 5 inserted into this trough 4.
Further, the outer surface of the trough 4 is provided with a jacket 7 for heating with steam or the like. Also, the gap B between the semicircular inner wall of the lower half of the trough 4 and the tip (outer) end surface of the blade 5 is equal to or less than the thickness of the chip used, for example, a plate-shaped chip with a length of 4 x width of 2 x thickness of 2 m/m, 2m/m or less for an elliptical shape with 4 major axis x 3 minor axis x 2 m/m thickness, and 3 m/m for a spherical shape with a diameter of 3 m/m.
m/m or less, but it is preferable to make this gap as small as possible from the viewpoint of quantitative performance.If it becomes larger than the thickness of the chip used, quantitative performance will deteriorate, and at the same time, the chip is likely to get caught, which can cause various problems. It will provoke. 8 is a driving motor. Reference numeral 9 denotes a conduction pipe that connects the hopper 1 and the vacuum vessel 2;
The degree of vacuum is almost equal, and the screw feeder 3
The difference in the degree of vacuum between the supply side and the discharge side disappears. 10
11 is a chip supply pipe, and 11 is a suction pipe connected to a vacuum generator 12 such as a steam ejector. In addition, 2
b is a discharge port for chips processed in the vacuum container 2; Chips are intermittently supplied to the hopper 1 in a vacuum-displaced state using two valves or containers, etc., so that the chips are between predetermined levels. The feed is carried out while being continuously heated by the screw feeder 3. That is, from the supply port 3a to the trough 4
The chips that have entered are sent to the discharge port 3b by the rotating screw blade 5 and supplied to the vacuum container 2.
In this case, since the degree of vacuum on the supply and discharge sides of the screw feeder 3 is kept almost the same by the conduit 9, the vacuum suction force will not cause the discharge to exceed its capacity. Almost no temporal variation occurs. Also, since the gap B between the inner wall of the lower half of the trough 4 and the outer diameter end of the screw blade 5 is set to be less than the thickness of the chip, the chip will not get caught in this gap, and therefore the feed rate will be constant. Quantitative performance becomes very good (accuracy usually ±1%), and there is no occurrence of fused and deformed chips, and there is no longer any trouble caused by sending out chips of inferior quality.

In this way, the chips are preheated and supplied to the vacuum container 2 with extremely high quantitative accuracy without degrading the quality, so that the processing in the vacuum container 2 is stable and it is possible to obtain a uniform and excellent quality product.

As explained above, according to the present invention, it is possible to continuously heat and supply synthetic resin chips to a vacuum container with extremely high accuracy and stably without causing problems such as loss of quality or inability to operate. It is possible to stabilize the process in the solid phase polymerization process and eliminate unevenness in the quality of the product, and its effects are very large.

[Brief explanation of the drawing]

1 is a layout diagram showing an embodiment of the present invention, FIG. 2 is a schematic sectional view of the screw feeder in FIG. 1, and FIG. 3 is a sectional view taken along the line AA in FIG. 2. 1...Hopper, 2...Vacuum container, 3...Screw feeder, 4...Trough, 5...Screw blade, 7
...jacket, 9...conducting pipe.

Claims (1)

[Claims] 1 In a processing method in which synthetic resin chips are continuously heated and quantitatively fed from a hopper to a vacuum container via a horizontal uniaxial screw feeder, the hopper and the vacuum container are connected with a conductive tube to reduce the internal pressure between the two. In addition to holding the screw feeder uniformly, the barrel of the screw feeder is made into a U-shaped trough-like body, and the gap between the lower semicircular inner wall of the trough-like body and the screw blade is set to be less than the thickness of the synthetic resin chip. A method for processing synthetic resin chips, characterized in that the synthetic resin chips are heated by a heating jacket formed on the outside of a trough-shaped body and fed into a vacuum container.