JPS6347802B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to highly oriented undrawn yarn (so-called POY) with excellent thermal dimensional stability and a method for producing drawn yarn from POY. This relates to a method for manufacturing at a relatively lower spinning speed than that of general POY. It has been shown in many documents that POY has a thermally stable structure (for example, Japanese Patent Publication No. 55-6729), and it is also known that fibers drawn from POY are thermally stable. (Unexamined Japanese Patent Publication No. 1973-
Publication No. 58031). Obtaining such POY at a relatively low speed is industrially useful because the final winding speed can be made relatively low when a drawn yarn is obtained using a spin draw method. Relatively slow and highly oriented
A technique for raising the temperature of the cooling air stream above room temperature in order to obtain POY is disclosed in Japanese Patent Application Laid-open No. 53-31815, but this method increases energy costs and is not necessarily industrially useful. hard. As a means to solve this problem, the present inventors overturned the common sense of using cooling air to cool the yarn in the melt spinning method, and came up with a method of spinning without actively cooling the yarn. . That is, in the present invention, when melt-spinning a thermoplastic resin, the spun yarn is cooled and solidified without actively using cooling air, and the yarn is bundled in a range of 20 to 100 cm below the solidification point, and the yarn is spun for 1500 m. This is a method for producing synthetic fibers with excellent thermal dimensional stability, which is characterized by drawing at a speed of 1/min or more.
Melt-spun thermoplastic resin such as nylon 66
Useful when manufacturing POY. For example, POY
When using POY for clothing after false twisting, the use of POY produced by the present invention results in extremely low stretch and false twisting properties, as there are fewer irregularities within and between the filaments, which are unique to POY, and in the longitudinal direction of the yarn. In good condition. Directly linking the spinning method according to the invention with a spin-drawing method is particularly suitable mainly for the production of industrial fibers. Intrinsic viscosity of thermoplastic resins, especially polyethylene terephthalate as the main component (measured at 30°C in a solvent of phenol/tetrachloroethane = 6/4)
0.70 or more is melt-spun from a spinneret at a discharge rate of 3.5 g/min or less per single hole, then cooled and solidified without actively using cooling air, so that the yarn tension at the solidification point is 1.5 x 10 ⁷ ~7.5×
Pull out the yarn so that it is between 10 ^{and 7} dyne/ ^cm2 ,
By focusing the yarns in the range of 20 to 100 cm below the solidification point and immediately drawing them by the spin draw method at a speed of 1500 m/min or more through the first stress isolation device, the present inventors' previous application Patent (patent application 1982)
194129), which has excellent thermal dimensional stability and chemical stability, as well as high strength, can be obtained at low cost. Next, the manufacturing method and technical background of such fibers will be explained. When spinning without actively using cooling air,
As the cooling of the yarn is delayed and the solidification point moves away from the spinneret, the tension at the solidification point of the yarn increases as air resistance increases, increasing the birefringence of the resulting POY. At the same time, the temperature difference between the inner and outer layers of the filament at the solidification point is significantly reduced, and as a result, the difference in the degree of orientation of molecular chains between the inner and outer layers of the spun filament is significantly reduced. However, when cooling air is used, differences in cooling conditions occur between rows of filaments, resulting in differences in the degree of orientation of molecular chains between filaments, which is particularly noticeable when using a spinneret with a large number of nozzle holes. However, according to the method of the present invention that does not use cooling air,
Such a problem does not occur. Therefore, the uniformity of the obtained POY inside and outside the filament is extremely good, and especially when it is stretched, the maximum stretching ratio is larger than that of POY produced by the prior art, which has the same average birefringence value, and the strength that can be obtained is inevitably becomes higher. In the present invention, the method of spinning without actively using cooling air means, for example, "Man-Made
Fibers chemical fibers co-translated by Ishikawa and Natsushina: Maruzen Co., Ltd. (5. Principles of melt spinning)” and “Polyester fibers Yokouchi and Nakamura translation: Corona Publishing (P142-143)”
As described in , contrary to the conventional method of actively using cooling air during melt spinning, in the present invention, the flow of air discharged perpendicularly to the spun filament is actively used. This is a method in which spinning is stopped and spinning is performed while the supply of cooling air is stopped while using a cooling chimney. If new equipment is to be installed,
In principle, it is sufficient to simply spin the molten polymer into the atmosphere, but even if it is spun into a room that is isolated from the outside air to the extent that is used in conventional methods, the yarn sways due to natural airflow inside the spinning chamber. In order to prevent such problems, it is preferable to provide partition walls surrounding the yarn in at least three directions before spinning. According to the spinning method of the present invention, POY which is suitable for industrial production and has excellent yarn physical properties can be obtained. A further technical advantage that should be noted is that the energy and supply equipment required to supply cooling air are unnecessary, and the equipment cost is greatly reduced. However, in such a method, the accompanying flow caused by the spun yarn tends to increase yarn wobbling and cause denier unevenness in the longitudinal direction of the yarn.W.Stein; Int.Text.Bull., World Ed.,
Spinning (3) 259 (1981)). Therefore, as a result of intensive studies on ways to prevent yarn wobbling caused by the accompanying flow, we found that by installing a yarn convergence device 20 to 100 cm below the point where the melt-spun yarn solidifies, the yarn wobbling caused by the accompanying flow can be prevented. discovered that it is possible to significantly reduce the The convergence position of the threads in the present invention is important.
(Measurement method will be described later) When the focusing position is less than 20 cm below the filament solidification point, a phenomenon in which the yarn gets caught in the focusing device sometimes occurs. Furthermore, if the convergence position is more than 100 cm below the solidification point, yarn sway occurs due to the accompanying flow, and the effect of the present invention is not recognized. When producing high-strength polyethylene terephthalate fiber suitable as a rubber reinforcing material for automobile tires etc. by the method of the present invention, it is preferable that the intrinsic viscosity of the polyethylene terephthalate is 0.7 or more, and if the intrinsic viscosity is less than 0.7, High-strength polyester fibers cannot be obtained and are not suitable for use as rubber reinforcing materials. In addition, during melt spinning, if the single-hole discharge rate exceeds 3.5 g/min, the difference in the degree of orientation of molecular chains between the inner and outer layers of the filament of the spun yarn increases, resulting in a low-shrinkage polyester with high strength. Fiber cannot be obtained. Next, the thread tension at the solidification point is
If it is less than 1.5×10 ⁷ dyne/cm ² , it is impossible to obtain a polyester fiber having low shrinkage, which is the most important effect of the present invention. Furthermore, if the yarn tension at the solidification point exceeds 7.5×10 ⁷ dyne/cm ² , it is recognized that the spun yarn has already crystallized (determined by wide-angle x-ray diffraction), and The intrafilament birefringence of the yarn becomes extremely large, resulting in a polyester fiber with low fiber strength after stretching. Furthermore, if the spinning speed is less than 1500 m/min, the pre-orientation of the fibers will decrease, and as a result, fibers with excellent thermal dimensional stability cannot be obtained. Several examples of the yarn converging device of the present invention are shown in FIGS. 1 to 6. FIG. 1 shows a yarn convergence device using a wide guide oiling device, and FIGS. 2 to 4 are detailed views of the wide guide oiling device. FIG. 5 is an example of a focusing device using a roller oiling device. FIG. 6 shows an example in which a godet roll is used as a focusing device. Of course, the focusing position is not limited to the above example, and any focusing device may be used as long as the yarn can be focused. Next, the present invention will be explained based on Examples. Example 1 A polyethylene terephthalate range having an intrinsic viscosity of 1.0 was melted using an extruder and spun under the conditions shown in Table 1. Thus obtained yarns A to C
As shown in Table 1, has a higher birefringence value at a lower spinning speed than Comparative Example D using the prior art using quenching air (active cooling air).
POY can be obtained, and at the same time, the birefringence difference within and between filaments is reduced compared to conventional
Extremely small compared to POY and has excellent homogeneity
You can get POY. Also, Worcester spot U%
Also, the same quality level as that of the conventional method can be obtained.

【table】

[Table] *Example 2, which refers to the vertical distance from the nozzle surface to the yarn convergence position. The results of a study on the yarn convergence position, which is an important component of the present invention, are shown below. Fig. 7 shows the relationship between the distance between the solidification point and the convergence position of the spun yarn and the Worcester spot U% when spinning was carried out under the same conditions as A in Example 1 and the convergence position of the yarn was changed. . As is clear from FIG. 7, it is preferable for the focusing position to be located 20 to 100 cm below the solidification point from the viewpoint of suppressing denier unevenness. Example 3 Spinning was carried out under the same conditions as in Example 1 B, and after passing through the first Godettrol (room temperature), it was immediately spun using high-temperature heated steam at 550°C.
It was stretched 2.21 times and passed through a second godet roll (temperature 200°C) with a circumferential speed of 4420 m/min, and then passed through a third godet roll (temperature 220°C) with a circumferential speed of 5080 m/min.
℃) and then stretched 1.149 times at a peripheral speed of 5000.
The yarn was relaxed by 1.6% using a fourth godet roll (temperature: 140°C) at a speed of 1.5 m/min, and then wound up. Shown in 2. The fiber of Comparative Example 1 had an intrinsic viscosity of 1.0, a diethylene glycol content of 1.0 mol%, and a carboxyl group content.
10 equivalents/10 ⁶ g of polyethylene terephthalate,
Polymer temperature is 310℃, single hole discharge rate is 2.32g/min, the number of nozzle holes is 190, the polymer is extruded from the nozzle cap, and the nozzle quench distance is 30cm and the wind speed is 0.4m/min.
sec, the yarn is cooled and thinned by cooling air at a temperature of 20℃,
It was spun at a speed of 700 m/min, and the average value of birefringence of the spun yarn at this time was 0.002, and the difference in birefringence between the filament surface and center of the spun yarn was 0.000.
The spun yarn was immediately subjected to a first drawing temperature of 95
°C, first stage stretching ratio 3.96 times, second stage stretching temperature 160
°C, second stage stretching ratio 1.25 times, third stage stretching temperature 220
It was obtained by stretching at a temperature of 1.15 times the third stage stretching ratio.

[Table] The fibers according to the present invention were found to have extremely superior thermal stability as compared to the comparative examples according to the prior art, and the usefulness of the present invention is clear. Next, a method for measuring the solidification point, which is an important technical point of the present invention, will be described. The change behavior of the diameter of the filament spun from the nozzle is measured using a Zimmer outer diameter measuring device, and the point at which no change in the diameter of the filament is observed is defined as the point of complete solidification. (Refer to P52 (1982) of the Proceedings of the Research Presentation at the 1982 Fiber Science Society Annual Conference)

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an example of the present invention using a wide guide oiling device as a focusing device, Fig. 2 is a sketch showing the wide guide oiling device, Fig. 3 is a plan view of the wide guide oiling device, and Fig. 4 is a sectional view taken along line A-A of the wide guide oiling device. FIG. 5 is an explanatory diagram showing an example of the present invention using a roller oiling device as a focusing position;
The figure shows that after using Godetstrol as a focusing device,
1 is a diagram illustrating an example of the present invention using a guide oiling device; FIG. Figure 7 shows the distance between the solidification point and the focusing position.
It is a figure showing the relationship between POY and Worcester's spot U%. 1...Spinneret, 2...Spun yarn, 3,3'...
Guide oiling device, 4... Godetstrol,
5... Solidification point, 6... Focusing position.

Claims (1)

[Claims] 1. When melt-spinning a thermoplastic resin, the spun yarn is cooled and solidified without actively using cooling air, and the yarn is focused in a range of 20 to 100 cm below the solidification point. ,
A method for producing synthetic fibers with excellent thermal dimensional stability, characterized by drawing at a speed of 1500 m/min or more. 2. The method according to claim 1, wherein the thermoplastic resin is polyester containing polyethylene terephthalate as a main component. 3. The method according to claim 1, wherein the thermoplastic resin is a polyamide containing nylon 6 and/or nylon 66 as a main component. 4 Intrinsic viscosity based on polyethylene terephthalate (phenol/tetrachloroethane 6/
Polyester (measured at 30°C in the solvent of No. 4) of 0.70 or more is melt-spun from a spinneret at a rate of 3.5 g/min or less per single hole, and then cooled without actively using cooling air to reach the solidification point. The yarn tension at
The yarn was pulled out at a speed of 1.5×10 ⁷ to 7.5×10 ⁷ dyne/cm ² , and the yarn was collected within a range of 20 to 100 cm below the solidification point, and the first
A method for producing polyester fibers with excellent thermal dimensional stability, characterized by obtaining drawn yarns by a spin-draw method immediately after passing through a stress isolation device.