JPS636647B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a direct spinning/drawing method for producing polyester fibers at higher speeds, simpler processes, and at lower costs. [Prior Art and Its Disadvantages] Direct spinning and drawing methods are already well known and are now widely adopted in production processes. For example, Japanese Patent Publication No. 50-3406 discloses that after the spun yarn is cooled and solidified, it is taken up by a first godet roller and subsequently guided to a second godet roller for drawing, and the undrawn yarn is preheated and drawn. We are proposing a method to do so. Further, a heated godet roller stretching method in which the first godet roller is heated is well known. In these methods, when drawing the undrawn yarn, the undrawn polyester yarn is preheated to a temperature higher than the glass transition temperature to facilitate the drawing. On the other hand, in recent years, there has been a demand for producing threads with simpler equipment, lower energy consumption, and lower cost. However, in the method using the first godet roller heated to 70 to 90 DEG C., a lot of effort was required to properly control the heating of the undrawn yarn in order to achieve uniform drawing. In other words, when heating the yarn with a hot roller to near the glass transition point of undrawn yarn, the heating state of the yarn changes depending on the oil/water content, the opening state of the yarn, the contact time with the roller, the ambient temperature near the roller, etc., and process control is affected. It was difficult in many ways. Furthermore, as a drawback of productivity, heating the first godet roller causes the yarn tension on the roller to be extremely reduced, resulting in increased yarn wobbling and yarn breakage. In addition, when the yarn sway on the second godet roller reaches around 5000 m/min, the airflow accompanying the rotation of the roller increases, which increases yarn sway, and even if it is a drawn yarn, it can cause yarn breakage if there is contact between yarns. It was hot too. Furthermore, since this conventional method is easy to handle as a heat source for hot rollers, it also uses an electric heater, which results in high electric heating costs, high equipment costs, and is complicated and requires high productivity when the stretching speed is less than 5000 m/min. The requirements were not satisfied and there was room for improvement. In order to improve the shortcomings of these conventional direct spinning and drawing methods, many proposals have been made in recent years for high-speed spinning methods that are particularly aimed at improving productivity by increasing the speed.
For example, in JP-A No. 55-107511, the spinning speed is
We are proposing a simple high-speed spinning method that creates a useful yarn structure that can withstand practical use without drawing (mechanical magnification) or heat setting by drawing at a speed of 4,500 m/min or more. The yarn quality obtained by this type of manufacturing method has a unique point in that it is essentially different in structure from the drawn yarn quality obtained by spinning at a low speed and applying a drawing ratio. For example, the elongation of a drawn yarn drawn at a spinning speed of 6000 m/min is 50 to 60%, and the boiling yield is extremely low to 2 to 3%. [Object of the invention] The inventors set the stretching and winding speed to 5000 m/min.
As a result of repeated studies on a simple high-speed direct spinning/drawing method with a focus on making the yarn physical properties similar to those of the conventional direct spinning/drawing method using heated drawing using a direct spinning/drawing method at 6000 m/min or more, we found that We have discovered a new and advantageous method, as detailed below. [Structure of the Invention] That is, the present invention melt-spun polyester, cooled and solidified it, then focused the yarn within 3 m below the spinneret surface, oiled it, and spun it at 4500 m/min or more using a mirror-finished non-heated first godet roller. Pick up, continue roughness 40~70Hrms ["Mechanical Engineering Handbook" 5th edition No. 17]
176-177 (Published by the Japan Society of Mechanical Engineers, June 15, 1977)], the polyester fiber is guided to a second godet roller with a satin finish and stretched between the first and second godet rollers. This is a spinning and drawing method. The present invention will be explained in detail below using figures. FIG. 1 is a schematic front view of a direct spinning and drawing apparatus showing one example of an embodiment of the present invention. Polyester is melted and discharged from a spinneret 1 to form an undrawn thread 2. After being cooled and solidified by the cooling device 3, a predetermined oil agent is applied to the undrawn yarns while converging the undrawn yarns by the oil supply device 4 provided within 3 m. And the non-heated first godet roller 5
It is taken over at a speed of 4,500 m/min or more, and then guided to the second godet roller 6 whose surface has been treated with a matte finish, and then the first
It is stretched between the godet roller 5 and the second godet roller 6 due to the difference in circumferential speed between both rollers, and a package 8 is obtained by a winder 7. If necessary, a focusing nozzle may be provided before the winder. The most distinctive feature of the direct spinning and drawing method of the present invention is that the first godet roller is not heated, unlike the conventional method. That is, in the present invention, the first godet roller is kept at normal temperature (room temperature) and is not preheated, so there is no decrease in yarn tension on the roller, and the first and second godet rollers are kept at room temperature.
There is very little yarn wobbling on the godet roller, which greatly reduces yarn breakage due to contact between yarns on the roller, improving productivity. In addition, by setting the take-up speed to 4500 m/min or more, the orientation will progress to a certain extent and the shrinkage rate will decrease.
For example, even if a heat setting treatment is performed after stretching, the heat setting temperature can be lowered, making it possible to significantly reduce electric heating costs. The first godet roller 5 is a roller that can rotate at high speed and only needs to have a circumferential speed of 4500 m/min or more, and is a short roller that does not require a heater. It is necessary to accurately regulate the undrawn yarn to a speed of 4500 m/min or more and take it off using the roller. Therefore, using a driven type or forced drive type separate roller 5',
The yarn may be wrapped around the first godet roller and the separate roller one or more times, and if the surface of the first godet roller is mirror-finished, the yarn will not slip, so it will not pass through the separate roller 5'. The take-up speed can be regulated by winding the first godet roller once or less. By adopting such conditions for surrounding the first godet roller, there is no need to use the long heating type first godet roller of the conventional method, and the number of windings is small, making it possible to make the equipment very compact and inexpensive. In addition, since the first godet roller is not heated, the yarn sway on the roller is greatly reduced, making it possible to take the yarn at high speed. In the present invention, before the yarn is taken up by the first godet roller 5, it is necessary to collect the yarn within 3 m below the mouth surface and to supply oil with the oil supply device 4. The yarn is bundled by the first Godet roller's take-up speed.
This is to prevent yarn breakage and yarn quality abnormalities due to the increase in yarn tension, which causes non-uniformity in the degree of single yarn orientation due to the extremely increased airflow accompanying the yarn by increasing the speed to 4500 m/min or more. The closer the oil supply device 4 is to the mouth surface, the smaller the degree of accompanying airflow, which makes it more effective.
Placing it too close to the cap before the solidification point is undesirable as it may cause thread breakage. As for the proper location, it is important to place it immediately after solidification, within a range of 3m below the mouth surface. If the lubricating device is located 3 m or more below the mouth surface, as described above, the air flow accompanying the yarn will increase at an accelerating rate due to high-speed take-off, resulting in yarn breakage and uneven yarn quality. As for the focusing method, it is most preferable to use a refueling guide that also serves as a focusing guide, but another guide may be provided immediately after the refueling device to perform focusing. On the other hand, in the present invention, it is extremely important that the second godet roller 6 has a matte surface.
This is advantageous because it prevents the yarn from wrapping around the roller and stabilizes the tension in the process. For this reason, it is preferable that the surface roughness of the second godet roller 6 is in the range of Hrms 40 to 70. If it exceeds Hrms 70, the yarn will slip on the roller, causing stretching unevenness.
If the Hrms is less than 40, yarn separation tends to worsen, and if the second godet roller is given a mirror finish, the yarn will frequently wind around the roller, making it difficult to obtain a stable drawn yarn, which is disadvantageous in terms of operation. If desired, the drawn yarn may be heat set by heating the second satin godet roller. By making the surface of the second godet roller matte, the regulation of the drawing speed becomes somewhat unstable, so a separate roller 6' paired with the second godet roller is used to pass the yarn onto both rollers one or more times. It is desirable to be surrounded. From the viewpoint of regulating the drawing speed, it is preferable to bend the film three or more times. In the present invention, the yarn, which has been bundled and oiled, is taken off by the first godet roller at a taking-up speed of 4500 m/min or more. When the take-up speed is less than 4,500 m/min, the yarn structure is in an undrawn region, so if the first godet roller is drawn without being heated (to above the glass transition temperature), Worcester spots will increase. That is, in the present invention, the take-up speed is set to 4500 m/min or higher to make the yarn structure before drawing as close to the drawn yarn structure as possible. The polyester of the present invention is mainly a polyester having ethylene terephthalate as a main repeating unit, but may also be a polyester having butylene terephthalate as a repeating unit. It may also be a polyester copolymerized with one or more other components in an amount of 15 mol% or less, and a polyester containing a small amount of additives. [Effects of the Invention] In the present invention, even when the yarn is taken off at such a high speed, the yarn quality remains the same as in the conventional method.
It has the advantage that the desired residual elongation can be freely selected between 20 and 45% by changing the stretching ratio applied between the godet rollers, and the shrinkage rate can also be selected to a desired level by heating the second godet roller. In addition, the present invention is a very simple process with low electric heating costs and can produce stable drawn yarn with high productivity. The present invention will be specifically explained below using Examples. Example 1 Polyethylene terephthalate with [η] = 0.65
It is melted at 90℃, extruded through a nozzle with 36 holes with a diameter of 0.3 mmφ, cooled, and 1.0% by weight of lubricant is applied to the yarn.Then, the conditions of the first godet roller and the second godet roller, and the oiling position are shown. After stretching with the same changes as in 1, the yarn was wound up to obtain a drawn yarn of 75d-36 filament. The quality of the yarn is shown in Table 1.
Note that the room temperature was 30°C. In addition, the surface roughness of the second godet roller which was satin finished was 55 Hrms.

[Table] Experiment Nos. 1, 2, 4, 6, 7, 10 and 12 show comparative examples for clarifying the effects of the present invention. No.
In methods 1 and 2, the first godet roller is preheated to 100°C and 80°C, which poses no problem in terms of yarn quality, but is not a satisfactory method because of large yarn fluctuation on the first godet roller, high electric heating cost, and high equipment cost. In Nos. 4 and 10, the surface of the second godet roller was mirror-finished, and the yarn did not easily separate from the second godet roller, and the yarn was often wrapped around the roller. No. 6 and 7 are cold stretching methods, so equipment costs,
Although the electric heating cost has been improved, there are drawbacks in terms of yarn quality, yarn breakage, and productivity due to the low take-up speed. No. 12 had a long distance to the refueling position, which caused an increase in accompanying airflow, and had the disadvantages of thread unevenness and thread breakage.
Compared to these, Example Nos. 3, 5, 8, 9 and 11
shows an excellent effect in which the above-mentioned drawbacks are eliminated. Example 2 A drawn yarn was obtained under the same conditions as in Experiment No. 3 of Example 1, except that the surface roughness of the second godet roller was variously changed. The quality of the yarn is shown in Table 2.

[Table] Experiments No. 13 and 16 are comparative examples for clarifying the effects of the present invention. In No. 13, the thread did not separate easily and was often wrapped around the roller. In No. 16, the drawing tension became unstable and uneven drawing occurred, making it impossible to obtain a stable drawn yarn.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of a direct spinning/drawing apparatus showing one example of an embodiment of the present invention. 1: Cap, 2: Yarn, 3: Cooling device, 4: Oil supply device, 5: First godet roller, 5': Separate roller, 6: Second godet roller, 6': Separate roller, 7: Winder, 8 :Package.

Claims (1)

[Claims] 1. After melt-spinning polyester and solidifying it by cooling, the yarn is bundled within 3m below the spinneret surface while being oiled and spun using a non-heated first godet roller with a mirror finish.
Pick up at 4500m/min or more, continue roughness 40~
A method for direct spinning and drawing of polyester fibers, characterized in that the fibers are guided to a second godet roller that has been subjected to a satin finish for 70 hours, and then drawn between the first and second godet rollers.