JPH043445B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for melt-spinning core-sheath type conjugate fibers, and more particularly to a method for melt-spinning fine core-sheath type conjugate fibers with excellent uniformity. [Prior Art] Thermoplastic polymers can be melt-spun into fibers with excellent mechanical properties, thermal stability, and good uniformity, and can be made continuously and stably at high speeds. Fiber can be obtained. In particular, melt spinning of fine core-sheath type composite fibers is a melt spinning method that takes advantage of the advantages of ordinary single-component fibers while producing fibers with properties that cannot be obtained with single-component fibers, and is of great industrial value. This is a high-quality spinning method. Conventionally, various devices and methods have been proposed as melt-spinning devices and methods for core-sheath type composite fibers, and among them, how to secure a flow path to the merging position of each component and how to merge and discharge the components has been proposed. There are many things that have been shown about this. Specific technical ideas include the measurability of each component, that is, ensuring that the core and sheath components always merge in equal proportions, and the concentricity, that is, how to arrange the core component in the center of the fiber. be. for example,
Japanese Patent Publication No. 35-2716 narrows the path of the components just before they merge in order to improve meterability. In other words, it is characterized by increasing speed. In addition, as an improvement method of this technology, for example, as in Japanese Patent Publication No. 44-7372, the speed of the core components immediately before merging is lowered to improve concentricity while ensuring high metrology.
There are some that increase the speed of the sheath component. As mentioned above, there are several inventions that refer to the speed of each component immediately before merging, but in all of them, the speed of the sheath component is relatively high. [Problems to be Solved by the Invention] However, when this technique is applied to fine-core core-sheath type composite spinning, it has the disadvantage that the number of yarn breakages is greater than that in single-component melt spinning. Especially when the spinning speed is
In the high-speed spinning region of 5000 m/min or more, yarn breakage occurs extremely frequently, making it impossible to achieve high productivity and low cost, which are the advantages of high-speed spinning methods. Furthermore, when paying attention to the discharge behavior, bending of the discharged polymer is often observed. Bending causes contamination of the spinneret, making it necessary to shorten the so-called spinneret correction cycle. An object of the present invention is to solve the above-mentioned problems in a melt-spinning method for fine-core conjugate fibers, ensure good spinning properties, and reduce the frequency of bending. [Means for Solving the Problems] The object of the present invention described above is to form a core-sheath type molten composite flow in which the volumetric discharge weight ratio of the core component to the sum of each component of the core and sheath is 20% or less, and then discharge the composite flow. In melt spinning of a thermoplastic polymer, which is performed by cooling and taking off, the composite spinning method is characterized in that each component when merging has an average discharge linear velocity that satisfies the following formulas (1) and (2). It can be achieved. V _A ≦20 …(1) V _B /V _A ≦0.08 …(2) [However, V _A is the average linear discharge velocity of the core component (cm/
V _B is the average linear discharge velocity of the sheath component (cm/sec)] The thermoplastic polymer used in the present invention is preferably a polymer that can be melt-spun, such as polyamide, polyester, polyethylene, polypropylene, polystyrene, or polyvinylidene chloride. used for. Further, the core component and sheath component used in composite spinning are usually composed of two or more types of substances having different properties, and can include any combination of the above polymers, but each component is composed of two or more types of the above polymers. It may be a mixture or a copolymer. Furthermore, each component has adhesiveness, hydrophilicity, lipophilicity, dyeability, color development, gloss, fluorescence, antistatic property, conductivity, antibacterial property, solubility, flame retardancy, heat resistance,
Inorganic particles for the purpose of imparting light transmittance and other functions.
The organic substance can be added and copolymerized in any amount and in any copolymerization amount. The core-sheath type molten composite flow of the present invention refers to a flow in which the sheath component completely covers the core component and heads toward the discharge hole.The cross section perpendicular to the flow direction is a concentric core-sheath, an eccentric core-sheath, or an irregular shape for both the core and sheath. It may also have a fibrous cross-sectional shape. What is the volumetric discharge ratio of the core component to the sum of each component of the core and sheath? Volumetric discharge ratio of the core component (%) = Volumetric discharge of the core component / Sum of the volumetric discharge of each component of the core and sheath x 100 Obtained from the formula. In a spinning device in which each component metered from a set of metering devices forms multiple composite streams and multiple filaments, the volumetric discharge rate of the core component is adjusted immediately before forming each composite stream. It is determined from the volumetric discharge ratio of each component. The volumetric discharge ratio of the sheath component is determined in the same manner as that of the core component. One of the common characteristics of fine core-sheath type composite fibers is that
Although the core component has excellent characteristics, it is either impossible to form it into a fiber by itself, or the mechanical properties, etc. that can withstand practical use are not satisfied. Therefore, the volumetric discharge ratio of the core component in the present invention needs to be 20% or less, and if it exceeds this, properties that can withstand practical use cannot be ensured. Further, from the viewpoint of spinning operability, this value is preferably 1% or more, more preferably 3% or more. Next, the average discharge linear velocity of each component in the present invention refers to the average discharge linear velocity of each component immediately before forming a composite flow, and generally the volumetric discharge amount of each component immediately before forming a composite flow is the composite flow. This is the value divided by the area of the cross section perpendicular to the flow of each component immediately before the flow is formed. Figures 1-6 show an example of the parts of the device that form the composite flow. The average ejection linear velocity of each component will be specifically explained based on each figure. _The average discharge linear ^velocities V _A and V _B of _the core _{and sheath} components in _{Figs .} These are the volumetric discharge amounts (cm ³ /sec) of the core and sheath components immediately before the discharge.) In Fig. 3, V _A and V _B are V _A =4W _A /πa ² V _B =4W _B /π (c ² − ^b2 ) becomes. V _A and V _B in FIGS. 4 and 5 are V _A =4W _A /πa ² V _B = W _B /πbt. V _A and V _B in FIG. 6 are V _A =4W _A /πa ² V _B =4W _B /πb ² . In the present invention, from the viewpoint of ease of manufacturing a device for forming a composite flow, as shown in Figs. A material that flows into the water is preferably used. In the present invention, V _A needs to be 20 (cm/sec) or less. When V _A exceeds 20, spinnability deteriorates significantly and bending appears in the discharged polymer. It is preferable that V _A be 0.5 or more from the viewpoint of ensuring metrology and ease of manufacturing the device. Also, V _B /V _A must be 0.08 or less.
When V _B /V _A exceeds 0.08, spinnability deteriorates significantly and bending appears. _VB /
V _A is preferably 0.001 or more, and more preferably 0.005 or more, since spinning properties become unstable if the discharge rate is reduced, and from the viewpoint of device operation. The poor spinnability that occurs when such a value is outside the range of the present invention is due to inherent defects in the yarn, so it is necessary to carry out the drawing process, the simultaneous drawing process,
This causes problems such as yarn breakage, fuzz, and wrapping during the temporary twisting process, yarn twisting process, and weaving and knitting process. Moreover, this poor spinnability is particularly noticeable in high-speed spinning, and yarn breakage and fuzz frequently occur at spinning speeds of 5000 m/min or higher. The cause of this is not clear, but if it falls outside the scope of the present invention, the average linear discharge velocity of the core component becomes too high, or the average linear velocity of the sheath component becomes faster than the average linear velocity of the core. If it is too high, the flow of the core component in the composite flow will be disturbed and unstable, the core component of the molten composite flow will become thick and thin, and the draft after discharge will not be distributed evenly in the fiber axial direction and cross-sectional direction. Therefore, it is thought that the thick and thin unevenness expands and the probability of thread breakage increases. In the present invention, after forming a core-sheath type molten composite flow, discharge,
Cooling and withdrawal are performed, but discharge here means
The composite flow is discharged into a gas at an average discharge linear velocity of preferably 1 cm/sec or more and 100 cm/sec or less, more preferably 3 cm/sec or more and 30 cm/sec or less. Further, the shape of the discharge hole can be arbitrary, such as round, T-shaped, Y-shaped, cross-shaped, slit-shaped, etc.
Five- to eight-lobed shapes are used. Cooling in the present invention refers to cooling the discharged molten material of the composite stream to below its melting point before being withdrawn, and in addition to active cooling using cooling air, a cooling bath, etc. Alternatively, the melt of the composite stream may be cooled to below its melting point in a pressurized or depressurized closed chamber before being taken out. In the present invention, taking-off refers to applying a draft to the cooled filament using active means, and a rotating body or a fluid suction device is preferably used. Although there is no limit to the take-up speed, it is preferably 10 m/min or more and 10000 m/min or less, more preferably 1000 m/min or less.
m/min or more. However, one of the objects of the present invention is to stabilize spinnability at take-off speeds of 5000 m/min or more, and it is particularly preferable to apply the present invention to take-off speeds of 5000 m/min or more. [Examples] The present invention will be explained in more detail below using Examples. Example 1 Polyethylene glycol diamine (number average molecular weight 4000) in which 97% or more of both terminals are amino groups was synthesized by reacting polyethylene glycol with acrylonitrile in the presence of an alkali catalyst and further performing a hydrogenation reaction. A 45% aqueous solution of polyethylene glycol diammonium adipate was obtained by subjecting adipic acid to a salt reaction using a conventional method. Add 200% of the above 45% polyethylene glycol diammonium adipate aqueous solution to a ^2m3 concentration can.
120 kg of 85% caprolactam aqueous solution and 16 kg of 40% hexamethylene diammonium isophthalate aqueous solution were charged, and heated under normal pressure for about 2 hours until the internal temperature reached 110°C, and concentrated to 80% concentration. Subsequently, the concentrated liquid was transferred to a polymerization can with a capacity of 800, and heating was started while flowing nitrogen into the polymerization can at a rate of 25/min. When the internal temperature reaches 120℃, add 5.2 kg of sodium dodecylbenzenesulfonate and 5.2 kg of 1,3,5 trimethyl-2,4,6-tri(3,5 di-tert-butyl4-hydroxybenzene)benzene. and start stirring until the internal temperature reaches 245°C.
Polymerization was completed by heating for an hour. After the polymerization is complete, pressurize the can with nitrogen at 7 kg/cm ² (G) and rotate the molten polymer into a belt approximately 15 cm wide and 1.5 mm thick using an endless belt (length 6 m, belt material: stainless steel, back side covered with water). cooled with spray) and extruded onto
After cooling, it was pelletized in the usual manner. The relative viscosity of the pellets obtained was 2.18.
Using a known composite spinning device, pellets made by mixing 10% by weight of the block polyether amide composition produced by the method described above with polyethylene terephthalate pellets with a modified intrinsic viscosity are used as the core component, and the pellets are spun from one hopper. Then, polyethylene terephthalate with an intrinsic viscosity of 0.63 was supplied as a sheath component from the other hopper, and the volumetric discharge ratio of the core component was set to 10%, and a concentric core-sheath type composite fiber was spun at a temperature of 290°C with a core and a core per hole. The sum of the volume discharge of each component of the sheath was set to 0.0196 cm ³ /sec, and the yarn was spun at a winding speed of 6000 m/min while interlacing was provided to obtain a 50 denier 24 filament yarn.
The cap is a = 0.02 (cm), b = 0.25 as shown in Figure 1.
(cm), and a composite cap with t=0.05 (cm) was used. At this time, the volumetric discharge amounts W _A and W _B of the core and sheath components per hole are 0.00196 cm ³ /sec and 0.0176 cm ³ /, respectively.
seconds, and the average discharge linear velocity V _A and V _B are respectively
6.24cm/sec, 0.449cm/sec, V _B /V _A = 0.072
It is. When the yarn was continuously wound for 10 hours, there was no yarn breakage, and when the wound package was observed, no fuzz was observed. Furthermore, when the mouthpiece was observed at this point, no bending had occurred in any of the 24 discharge holes. Examples 2 and 3/Comparative Examples 1 to 3 Spinning was carried out in accordance with Example 1, except that the ratio of the volume discharge amount of the core and sheath components per hole was changed. The results are shown in Table 1. The number of yarn breaks and the number of fluffs generated during spinning are the results of winding for 10 hours.

[Table] When the mouthpiece was observed in the same manner as in Example 1, bending was observed in the discharge holes 1 to 8 of the mouthpiece in all comparative examples. Example 4/Comparative Examples 4 to 6 Spinning was carried out in the same manner as in Example 1, except that the die was changed and the average linear discharge velocity of each component was changed. At this time, use a base merging part that resembles the one shown in Figure 1,
The average ejection linear velocity of each component was changed by changing the values of each dimension a, b, and t. The results are shown in Table 2.

[Table] As shown in Table 2, those whose values of V _A and V _B /V _A were within the range of the present invention had extremely good spinnability. [Effects of the Invention] As described above, the present invention prevents yarn breakage and fluff during spinning by specifying the discharge linear velocity just before each component joins in the composite spinneret in fine core-sheath type composite spinning. This prevents the occurrence of polymer bending and also suppresses the bending phenomenon of the polymer. It is believed that by meeting the requirements of the present invention, the flow after merging became extremely stable, and the discharge behavior and fibrillation behavior after discharge became stable, resulting in improvements. The composite fiber spun according to the present invention does not contain defects such as fuzz in the spun package, so it has good resistance to drawing, drawing twist, generation of fuzz during weaving and knitting, and thread passability in each process. Summer. The final product is of excellent quality, taking advantage of the high value of the fine core-sheath composite fiber. Furthermore, by applying it to high-speed spinning, it is possible to stably obtain fibers that can be used for practical purposes without drawing, and it has become possible to produce high value-added fibers at an extremely low cost.

[Brief explanation of drawings]

FIGS. 1 to 6 show a portion of a device for forming a core-sheath type molten composite flow preferably used in the present invention for forming a composite flow.

Claims (1)

[Scope of Claims] 1. A thermoplastic polymer that is discharged, cooled, and withdrawn after forming a core-sheath type composite melt flow in which the volumetric discharge ratio of the core component to the sum of each component of the core and sheath is 20% or less. In melt spinning, each component when merging is as follows.
A composite spinning method characterized by an average discharge linear velocity that satisfies equations (1) and (2). V _A ≦20 …(1) V _B /V _A ≦0.08 …(2) [However, V _A is the average linear discharge velocity of the core component (cm/
sec) V _B is the average discharge linear velocity of the sheath component (cm/sec)]