JPH0343364B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention relates to a spinneret for melt-spinning a thermoplastic polymer material capable of being melt-spun. More specifically, the present invention provides a single spinneret that can produce mixed fiber yarns with different elongation at low cost, a single spinneret that can produce low elongation spun yarns at low spinning speeds, and a single spinneret that can produce yarns with high dyeability. This invention relates to a single base capable of producing yarn. (2) Prior art Conventionally, spun yarns with different elongation are air-entangled and then subjected to drawing heat treatment, or after drawing heat treatment, entangling treatment is performed to obtain yarns with different yarn lengths and weaving with a good surface texture. By forming a knitted fabric and by twisting the spun yarn having this difference in elongation (including simultaneous stretching and false twisting (DTY)), high elongation yarn is sheathed in a low elongation yarn core. It is a well-known technique to produce woven or knitted fabrics with improved texture and texture. Conventionally, methods for manufacturing yarns having different elongation include the following methods. A method in which yarns with different spinning speeds are separately spun and then used by combining them; (for example, undrawn yarn (UDY) with a spinning speed of about 1500 m/min and
Splicing yarn with partially oriented yarn (POY) at around 3500m/min.
Splicing of drawn yarn (FOY) and POY, splicing of USY and FOY at a spinning speed of about 5000 m, USY, POY and plywood, etc.) Methods for imparting a difference in elongation during spinning are (a) One side is straight during spinning. Perform stretching (SDY),
(b) During spinning, one thread is passed through a non-contact heating heater installed at a certain distance after exiting the spinneret.
(c) During spinning, one is subjected to non-contact heating directly under the spinneret to increase the elongation, while the other is heated directly under the spinneret to increase the elongation. A method in which one yarn is cooled to lower its elongation, then the yarn is doubled and then taken simultaneously. (d) One yarn is made into an irregular cross-section, such as an oblate yarn, to increase the cooling effect, and the other is made into a normal round cross-section, and the yarn is doubled and then wound. (e) A method in which the yarn is wound up after being doubled. (f) As described in JP-A No. 58-149309, there is a known method for spinning by providing a cooling effect by providing unevenness on the discharge surface of the spinneret. There is. Furthermore, in addition to these (a) to (f), there is also a method (g) in which not the same polymer but polymers with different elongations are spun at the same spinning speed using separate spinning machines and wound at the same time. However, the above-mentioned conventional techniques have various problems. Although it is possible to obtain a mixture of yarns with different spun speeds, the spinning productivity is poor because they are not wound at the same time, and one additional step is required, or a separate creel stand is required during drawing or DTY processing. It is necessary to provide Furthermore, when producing by the SDY method, a direct stretching process is required in addition to a simple spinning process, and furthermore, it is difficult to obtain an arbitrary difference in elongation. For example, elongation of 80% or more
SDY has large stretching spots, and therefore large staining spots and denier spots. Furthermore, the method of lowering the elongation by using a heating heater during the spinning process has problems such as complicating the process and unevenness between the spindles. It is difficult to control the elongation difference and the natural draw ratio (NDR) arbitrarily over a wide range, and it is not suitable to perform these operations within the same die. On the other hand, lowering the elongation by using a highly irregularly shaped cross section, which can improve the cooling effect, does not allow for a large difference in elongation and is limited by the irregular shape. Furthermore, in the method of making the cap surface uneven, it is not possible to freely create a difference in elongation. In particular, if the cooling of the convex portions where the elongation becomes low progresses too much, the yarn will become weak and continuous spinning will not be possible. (3) Purpose of the invention Therefore, the purpose of the present invention is to solve the various problems and drawbacks mentioned above, and to make it possible to lower the elongation of spun yarn even in the lower spinning speed range than before, and as a result, to make it possible to reduce the elongation of the spun yarn even in the low spinning speed range. It is possible to simplify and rationalize the process by imparting an elongation difference or NDR difference between spun yarns and also preventing light dyeing of low elongation side yarns, which is another drawback of conventional technology. The object of the present invention is to provide a spinneret that allows stable spinning. 3. Structure of the Invention According to the present invention, the polymer melt path following the terminal end 4 of the normal discharge hole 3 is configured as a cylindrical or divergent passage 6 having a diameter larger than the diameter (D) of the discharge hole 3, At this time, the tip of the needle-shaped object 7 inserted through the discharge hole 3 and the passage 6 is 3.
A melt spinneret characterized by having a spinning hole that protrudes by mm or more. is provided. Examples of the polymer to be melt-spun in the present invention include polyester, polyamide, and polypropylene, among which polyester is most preferably used. Next, the spinneret of the present invention will be explained with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view of a main part of a spinneret having a conventional spinning hole, and FIG. 2 is a longitudinal cross-sectional view of a main part showing an embodiment of a spinneret having a spinning hole according to the present invention. As shown in FIG. 1, a normal spinning hole has a so-called spinneret plate 1 containing a polymer introduction part 2 and a discharge hole 3, whereas the spinning hole of the present invention The hole (cap) has two major features as shown in FIG. That is, the first
Continuing from the terminal end 4 (discharge hole end) of the discharge hole 3, which is usually referred to as a mouthpiece, there is a cylindrical or flared polymer passage 6 having a diameter larger than the discharge hole diameter (D), and a polymer passage 6 having a diameter larger than the discharge hole diameter (D). A needle-like object 7 is inserted into 2 so as to coincide with the center axis of the discharge hole 3 and the surface passage 6, and the tip 8 of this needle-like object and the lower end 9 (path end) of the passageway are inserted. The distance l is 3 mm or more. Of the above two features of the present invention, the latter, the spinneret arranged so that the needles 7 pass through the discharge hole 3 and protrude to the downstream of the spinneret plate, is particularly important, and the polymer flow liquid flows through the needles. Since the polymer flows down along the nozzle 7, it has the effect of alleviating the rapid stress deformation of the polymer flowing liquid immediately after the discharge hole end 4, which normally occurs at the nozzle, and as a result, spinning is possible at a low nozzle temperature and at a lower spinning speed than usual. This provides the effect that it is possible to obtain a spun yarn with low elongation, and also to obtain a yarn with higher dyeability than usual. Next, the feature of the former is that the passage (flow) path 6 following the discharge hole end 4 allows the temperature gradient, viscosity gradient, and velocity gradient of the polymer flow flowing along the needle-shaped object 7 to proceed smoothly and uniformly. In addition, it alleviates and prevents the influence of the cooling atmosphere under the cap and the flow accompanying the yarn, and also prevents dirt on the cap surface 5 due to oozing and accumulation of polymers and foreign matter in the polymer that are normally found on the cap surface, and this dirt. It has the effect of preventing bending and kneeing caused by the process, and as a result, there is no need to clean the spinneret (surface) due to the adhesion of polymers, etc., and in addition, it has the effect of extremely stable spinning of homogeneous spun yarn. They will provide it to you. Here, FIG. 3 is a perspective view showing an example of the needle-like object 7 portion. In FIG. 3, the needle-like object 7 has a plurality of (four in this example) blades 10 installed at equal intervals in the circumferential direction of the needle-shaped object 7 to form an assembly. This needle assembly is inserted into the spinning hole as shown in FIG.
is fixed to the top of the Here, the shape of the upper part of the needle assembly shown in FIG. 3 is shown as a four-blade type, but
The function of this part is to firmly fix the needle-like object 7 to the spinning hole, and to form and hold a passage for guiding the polymer flow liquid to the discharge hole 3. Therefore, the shape of the upper part is not limited in any way, and a shape in which a plurality of small circular polymer liquid inflow holes are provided at equal intervals in the circumferential direction may also be used. Further, the shape of the needle 7 of the needle assembly shown in FIG. 3 is cylindrical in this example, but is not particularly limited, and may be a cone with a sharp tip. , also, elliptical cylinder (cone),
Polygonal prisms (pyramids) such as triangular prisms (pyramids) and pentagonal prisms (pyramids),
Other types of irregular cross-section columns (cones) are also acceptable. Furthermore, by using circular tubes, polygonal tubes, and various other shapes of hollow tubes with irregular cross sections, it is possible to spin hollow fibers. It is also possible to apply needles to composite spinnerets of the type. The outer diameter of the needle-like object 7 is desirably approximately 0.3 mm or more, preferably 0.5 mm or more, in order to reduce deformation due to bending, etc., and considering ease of handling and maintainability. Since there is a natural relationship with the diameter (D) of the discharge hole 3 depending on the fineness (De) of the thread, etc., the upper limit of the outer diameter of the needle-like object 7 should be at least 0.1 mm vertically smaller than the discharge hole diameter (D). Preferably, the combination of the outer diameter of the needle-like object 7 and the discharge hole (D) can be arbitrarily adjusted within this dimensional relationship. The axis of the above-mentioned needle-shaped object 7 coincides with the axes of at least the introduction hole 2 and the discharge hole 3, and the discharge hole 3,
It projects downward from the passage end 9 through the passage 6. In the spinneret of the present invention, the shape of the discharge hole 3 is generally similar to that of a normal spinneret, but the dimensions are generally larger (diameter) than those of a normal spinneret.
(approximately 0.8 to 5 mm) is adopted. Next, another feature of the present invention is the discharge hole end 4.
The passage 6 following 2 will be explained in more detail. As shown in the embodiment of FIG. 2, the passage 6 basically has an inner diameter (A) on the upstream side, an inner diameter (B) at the downstream passage end 9, and a distance (L) between the discharge hole end 4 and the passage end 9. It is configured. Normally, after a viscoelastic polymer fluid leaves the discharge hole, its diameter increases and bulges.
A so-called balance effect can be seen. This balancing effect is said to be a phenomenon that occurs because the discharge velocity distribution of the polymer flow at the end of the discharge hole is relaxed after discharge and the velocity distribution is made uniform. The ratio of the discharge hole diameter and the maximum diameter of the polymer flow due to this ballast effect (balance ratio) changes depending on the viscosity of the polymer flow, the discharge speed, etc., but in general the ballast ratio is 1 to 2.5 (in extreme cases 1 to 2.5).
8). Further, the maximum diameter of the polymer flow is approximately 1 to 10 mm from the mouthpiece (discharge hole end). Therefore, it is necessary to design the dimensions, etc. of the passage 6 of the base of the present invention, taking this balancing effect into full consideration.
In the process of polymer flowing down this passage 6, the velocity distribution of the polymer should be made uniform without being affected by the atmosphere directly below the nozzle, and it is meaningless to make the polymer flow extremely larger than the maximum diameter. However, making it extremely small is not preferable because it will obstruct the flow of the polymer and disturb the uniformity of the velocity distribution. Therefore, in the passage 6 shown in FIG. 2, the ratio A/D between the upstream diameter A and the discharge hole diameter D is 1 to 3, the ratio B/A between the upstream diameter A and the downstream diameter B is 1 to 3, and the discharge hole end 4
The distance L between the path end 9 and the end 9 is 1 to 10 mm, preferably 3 mm.
~7 mm is adopted, but there is no particular limitation. The positional relationship between the needle-like object 7 and the passage 6, which is a feature of the present invention, is determined by the distance l between the passage end 9 and the needle-like object tip 8 shown in FIG.
It depends on the diameter of the needle, the viscosity of the polymer flow, the discharge amount, the spinneret temperature, etc., but it is 3 to 30 mm, preferably 5 mm.
~20mm is used. This distance l (protrusion length)
If the spinneret is small, as with a normal spinneret, the stress deformation of the polymer liquid immediately after the end of the discharge hole will be rapid, and even under conditions where the spinneret temperature is not much lower than normal, weak yarn or yarn breakage will occur, making stable spinning difficult. The effect of low-temperature spinning, which is a basic feature of the invention, cannot be sufficiently obtained. On the other hand, if the protrusion length l is extremely large, cooling will proceed as the polymer liquid flows down along the needle-like object 7, and in extreme cases, the polymer may solidify and threading may become impossible. So I don't like it. Note that the spinneret of the present invention is characterized by needles and a passageway following the discharge hole, and is not particularly limited with respect to dimensions other than those described above. Figure 2 shows
The discharge hole end 4 coincides with the mouth surface 5 of a normal mouthpiece,
In one embodiment, the passage 6 protrudes from the mouthpiece surface 5, and FIG. 4 shows another embodiment in which the passageway end 9 coincides with the mouthpiece surface 5. Furthermore, FIG. 5, which is in an intermediate positional relationship with FIG. 2, can also be cited as another embodiment of the present invention. Another embodiment of the present invention is shown in FIG. 6, which has a passageway 11 that widens toward the end and connects the discharge hole end 4 and the upper part of the passageway 6. Furthermore, the discharge hole diameter and the upstream diameter of the passage (A) match,
Another embodiment of the present invention is shown in FIG. 7, which shows a passageway that diverges downstream. The spinneret of the present invention explained above (Fig. 2,
Melt spinning is performed using any one of the methods shown in Figures 4 to 7), but in order to more effectively exhibit the effects of the present invention, the spinneret temperature must be adjusted to (the melting point of the polymer +
5) It is preferable to carry out melt spinning in a range of not less than 0.degree. C. and not more than the lower limit spinneret temperature in a normal spinneret. An aspect of the spinneret of the present invention is one having at least one spinning hole consisting of a passage connected to a discharge hole and a needle-like material, and is suitable for use in a monofilament with one hole or a multifilament with a plurality of holes. It is not particularly limited. In addition, there are usually spinning holes (circular,
(including irregular cross-sectional holes) may be provided on the cap. (5) Functions and Effects The characteristics of the spun yarn obtained by melt spinning using the spinneret of the present invention and the characteristics of spinnability will be described below. First, it is possible to spin at a spinneret temperature lower than that of a normal spinneret, in other words, low-temperature spinning is possible.
This is one of the effects of the needle-like material, and since the polymer spins in a conical or icicle-like shape while being cooled along the needle-like material, it can be spun without breaking even at low temperatures. be. In conventional spinnerets, when the spinneret temperature is lowered, there is a temperature at which the yarn breaks, which is called the weakening spinneret temperature or the lower limit spinning temperature, but in the spinneret of the present invention, this lower limit temperature for spinning is lower than that of a normal spinneret. If the spindle temperature is at least (melting point +5)°C of the polymer, spinning can be performed. Secondly, even at the same spinneret temperature and the same spinning speed, a spun yarn with lower elongation than conventional spun yarns can be produced. Therefore, a spun blend yarn having a difference in elongation can be easily obtained. Generally, in normal spinning, the elongation of the spun yarn decreases as the spinning speed increases, and as the single yarn denier of the spun yarn increases, the elongation and NDR increase even at the same spinning speed. In the case of polyester, its elongation value is approximately 200 to 250% in the range called UDY at spinning speeds of 500 to 2000 m/min, and approximately 200 to 250% at spinning speeds of 2800 to 3500 m/min.
200-130% in POY range, spinning speed 4000-6000
In the high speed spinning (USY) range of m/min, it is about 100 to 50%. On the other hand, as in the present invention, the elongation of the yarn is within the UDY spinning speed range due to spinning from a needle-like object in the center of the spinning hole that protrudes downward from the spinneret plate. In the POY spinning speed range, it can be changed by 200 to 50%, and in the USY spinning speed range, it can be changed by 100 to 50%. This is because the viscosity of the molten polymer is increased by cooling it while running it along a needle-shaped object and spinning is performed, which can lower the elongation. Therefore, if the protruding length of the needle-like object is shortened, the elongation becomes high, and if it is made long, the elongation becomes low. One of the applications that exhibits the effects of the present invention is elongation differentially spun blended yarn, but of course, the yarn may be spun separately from the spinneret of the present invention and the normal spinneret and then combined at the time of winding. It is most rational to use a spinneret that has a normal spinning hole and a spinning hole of the present invention in the same spinneret. In the case of mixed fiber yarns, if air entanglement treatment is performed during winding, before and after oiling, or between take-up rollers, it is expected that handling in the subsequent process will be improved and the texture will be improved due to the mixed fiber state. In addition, when obtaining a mixed fiber yarn using the spinneret of the present invention, the spinning speed, spinneret temperature, protrusion length of the needles, etc. are changed in order to obtain the desired elongation and elongation difference. Just set it. In addition, it is not limited to yarns with a fixed length of needle protrusion and mixed yarns from normal spinning holes, but also blends with various lengths of needle protrusion and two or more different elongation differences. The term also includes the production of mixed fiber yarns using fiber yarns or a combination of these yarns and ordinary spinning holes, and does not specify the arrangement of these fibers in the spinneret. The yarn spun as described above may be subjected to direct spinning drawing (SDY), or may be once wound and then subjected to the next step of drawing or DTY processing. Thirdly, the spun yarn from the spinning hole having needle-like objects is
There is a tendency for yarns spun from normal spinning holes to be dyed darker than yarns with the same elongation, and this also applies to yarns that have been subjected to drawing heat treatment or DTY processing under the same conditions. A mixed fiber yarn of high elongation yarns and yarns from spinning holes having needle-like objects has a characteristic that the difference in dyeing is close to each other, and unevenness and irritation due to dyeing are reduced. The cause of this dark dyeing is that even in normal spinning, as the spinning speed increases (UDY, POY, USY), it is well known that drawn yarns and DTY yarns tend to become dark dyed. This is considered to be an extreme phenomenon. The fourth feature is due to the passageway following the discharge hole. This passage does not impair the first to third characteristics, which are mainly the effects of the needle-shaped objects, but rather enhances them, and makes it possible to stably spin an extremely homogeneous yarn. That is, this passage allows the temperature gradient, viscosity gradient, and velocity gradient of the polymer flow flowing along the needle to proceed smoothly and uniformly, and also alleviates the influence of the cooling atmosphere under the mouthpiece and the flow accompanying the yarn. It also has the effect of preventing the polymer normally found on the mouthpiece surface and dirt on the mouthpiece surface due to oozing and accumulation of foreign matter in the polymer, as well as bending and kneeing caused by this dirt on the mouthpiece surface.
As a result, the cap (surface) due to adhesion of polymer etc.
This eliminates the need for cleaning at all, and in addition provides the effect of extremely stable spinning of homogeneous spun yarn (represented by μ%). (6) Example Polyethylene terephthalate with an intrinsic viscosity [η] of 0.64 was melted at 295°C, and using a normal spinning device,
Hole diameter (D) 0.3mmφ as a normal hole (high elongation side) in the cap,
Using the needle-shaped object of the present invention having a length of 0.6 mm and a number of holes of 24 H as a spinning hole with a passage (low elongation side), the structure shown in Fig. 2 and the number of holes of 12 H were provided in the same spinneret. spun. In Fig. 2, the spinning hole having needles and a passageway has a hole diameter (D) of φ1.0mm, a length of 2.0mm, a needle diameter of φ0.7mm, and an upstream diameter of the passageway (A ) = φ2.0mm, downstream diameter (B) = φ4.0mm, distance L between discharge hole end 4 and passage end 9 = 5mm, and protrusion length of the needle (between passage end 9 and needle tip 8). distance l)
The material was cooled in air at 25° C. by varying the spinneret temperature and spinning winding speed, and after being coated with an oil agent, it was wound up. Table 1 shows the spinning conditions, elongation at break, and difference in elongation of these mixed yarns. In addition, the single yarn De on the high elongation side
The single yarn De on the low elongation side is approximately 1:1.6. As is clear from Table 1, at low spinning speeds in the UDY range, the elongation ratio of the yarn from needles can be as low as that of normal POY, and at spinning speeds in the POY range,
It is clear that elongation as low as USY is possible. In addition, with respect to the elongation from the normal spinning hole,
It has been shown that an elongation difference of about 140% to 50% can be obtained in the UDY range, and an elongation difference of about 70% to 30% in the POY range. Although it is not shown in Table 1, it is possible to obtain mixed fiber yarns with higher physical property differences by combining the shape, length, passage shape, and mouth temperature of the needles, as well as conventional technology. It is clear. In particular, as a result of continuous spinning for 7 days for Experiments No. 7 and 10 shown in Table 1, the U% and fluff of the spun yarn were 0.6% for No. 7, 0 yarn/2000m, and 0.6% for No. 10, respectively. 0.5
%, 1 piece/2000m, extremely homogeneous yarn was obtained, and in addition, there was no polymer adhesion in the spinning holes of the present invention, the polymer flow was straight, there was no yarn shaking, and there were no problems such as yarn breakage. There was no problem at all, and stable spinning was possible. 【table】

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view of the main parts of a normal spinneret, Figure 2
The figure is a vertical cross-sectional view of a main part of a spinneret showing one embodiment of the present invention, FIG. 3 is a perspective view showing an embodiment of the needle-like part in FIG. 2, and FIGS. FIG. 7 is a vertical cross-sectional view of main parts showing another embodiment of the cap. 1...Match plate, 2...Introduction hole, 3...Discharge hole,
4... Discharge hole end, 5... Mouth surface, 6... Passage, 7
... Needle-like object, 8 ... Needle-like object end, 9 ... Passage end, 1
0... Feather.

Claims (1)

[Claims] 1. The polymer melt flow path following the terminal end 4 of the normal discharge hole 3 is configured as a cylindrical or divergent passage 6 with a diameter larger than the diameter (D) of the discharge hole 3, and The needle-shaped object 7 inserted through the discharge hole 3 and the passage 6
1. A melt spinneret characterized by having a spinning hole in which a tip 8 of the passage 6 projects beyond the lower end of the passage 6 by 3 mm or more. 2. The polymer melt channel following the end 4 of the conventional discharge hole 3 is configured as a cylindrical or flared passage 6 with a diameter larger than the diameter (D) of the discharge hole 3, in which case the discharge hole 3 and the passage needle-shaped object 7 inserted through 6
The melt spinneret is characterized by having a spinning hole in which the tip 8 protrudes beyond the lower end of the passage 6 by 3 mm or more, and a normal spinning hole in which the needle-shaped object is not inserted. A melt spinneret characterized by: