JPS6128012A - Method for melt spinning modified cross section fiber - Google Patents

Abstract

PURPOSE:To obtain the titled fibers having a high modification ratio of cross section, by directly extruding a melt into a pressurized chamber, having a flow inlet, and outlet of a gas, and kept under a high pressure, cooling and solidifying the resultant filaments, leading the filaments from a sealed filament outlet to a part under ordinary pressure, and taking off the filaments. CONSTITUTION:A sealing guide 10 for substantially sealing the jetting of a pressurized gas is provided at a filament outlet provided at the bottom of a pressurized chamber 5 provided just under a spinneret 1, and the interior of the pressurized chamber 5 is kept under >=1.0kg/cm<2>G pressure. A melt is extruded into the pressurized chamber 5 kept under >=1.0kg/cm<2>G pressure, and the resultant filaments are cooled and solidified in the pressurized chamber 5, and led to the outside of the pressurized chamber 5 by a taking off device.

Description

Detailed Description of the Invention [Industrial Field of Application 1] The present invention uses a melt spinning method to produce synthetic fibers that maintain a high degree of irregular cross-section and have excellent uniformity, strength, elongation, and physical properties (1 = irregular shape, cross-section). It's about how to do it.

[Prior art] Conventionally, in order to improve the gloss and texture of synthetic gAN fabrics, the cross-sectional shape of fibers has been modified to create fibers with modified cross-sections, such as thermoplastic synthetic fibers such as polyamide and polyester. It is widely practiced in Generally, in the method of obtaining irregular cross-section fibers by the melt spinning method, the second
As shown in the figure, fibers are often spun from a spinneret for shell-shaped cross-section fibers with holes in the form of a combination of linear or arcuate slits, cooled, and solidified to give the fibers an irregular cross-section.

Furthermore, in recent years, research and development of special irregular cross-section fibers has been actively conducted with the aim of imparting various functionalities (water absorption, hygroscopicity, flame retardance, antistatic properties, etc.). In order to sufficiently reduce the effects of these cross-sectional deformities,
It is effective to increase the degree of irregularity of the mH cross section, and various studies have been conducted on ways to increase the degree of irregularity.

Generally, the degree of cross-sectional irregularity of the obtained uAN depends on the hole shape of the spinneret, the properties of the molten polymer (melt viscosity, elastic recovery strain, surface tension, etc.), and various spinning conditions (discharge rate, spinning temperature, spinning speed, It is affected by various factors such as atmospheric pressure, cooling rate, etc. By varying these factors,
Even if an attempt is made to increase the degree of abnormality, the range in which it can be adopted is narrow, and the reality is that no great effect can be obtained.

Furthermore, as disclosed in Japanese Patent Application Laid-open No. 140620/1983, l! There is also a method of increasing the degree of irregularity of the fibers, or a method of increasing the degree of irregularity of the fibers by extremely rapidly cooling the discharged polymer stream directly below the die.

However, if the degree of deformation of the spinneret hole is increased, the total length of the slit will inevitably become longer and the area of the slit will become larger. Therefore, when spinning filament yarn with a small single filament fineness, the pressure on the back of the spinneret during spinning will decrease. However, there were disadvantages in that problems such as yarn unevenness and yarn breakage were more likely to occur due to the method of discharging the polymer from the nozzle hole.

In addition, if the polymer flow is rapidly cooled by extremely strong cooling air directly under the spinneret, the cooling of the yarn becomes uneven, the strength and elongation of the resulting filament yarn decreases, and yarn unevenness increases, so it is not suitable for practical use as a filament yarn. It is difficult to obtain yarn that can withstand this.

As described above, in conventional methods, when attempting to obtain irregular cross-sectional fibers with a high degree of cross-sectional irregularity even with polymers with relatively high melt viscosity such as nylon 6 and polyester, disadvantages such as yarn unevenness and decreased strength and elongation occur. Furthermore, with a polymer such as nylon 66 having a low melt viscosity, it is difficult to obtain a modified cross-section fiber having a degree of irregularity comparable to that of nylon 6 or polyester and having good uniformity and strength and elongation properties.

[Problems to be Solved by the Invention] The present invention solves the problems of the prior art described above, that is, it does not increase the degree of deformation of the spinneret hole, and furthermore, it solves the problem of special spinning conditions. It is possible to create irregular cross-sectional fiber yarns with large cross-sectional irregularity and excellent uniformity and strength and elongation properties without using any other materials. The main object of the present invention is to provide a method for melt-spinning irregular cross-section fibers, which can stably spin irregular cross-section synthetic fiber yarns with excellent fiber properties.

[Means for Solving the Problems] In order to achieve the above object, the present invention involves spinning a molten thermoplastic polymer from a fiber yarn spinneret with an irregular cross section, cooling and solidifying the spun yarn, and then taking it off. In the method for obtaining irregular cross-section fibers, 1. The molten thermoplastic polymer is directly spun into a pressurized chamber that is maintained under high pressure conditions of Okp/cfG or higher and has a gas inlet and an outlet, and the spun yarn is cooled and solidified in the pressurized chamber. After this, the cooled yarn is transferred to the normal pressure section from the yarn outlet provided at the bottom of the pressurizing chamber and sealed to substantially prevent the pressurized gas from blowing out, by means of a take-up means outside the pressurizing chamber. The object of the present invention is to provide a melt-spinning method of irregular cross-section mis, which is guided and drawn.

[Function] In the present invention, in order to obtain a modified cross-section fiber that has a large degree of irregularity to the extent that the desired effect of the irregular cross-section can be exerted and has excellent uniformity and strength and elongation characteristics, a 1
, to 0! It is necessary to spin the fibers into a pressurized chamber with a pressure of It/ff1G or higher, and to cool and assimilate the fibers in the pressurized chamber. In the method (Japanese Patent Laid-Open No. 71922/1983) in which the spun fibers are cooled under normal pressure and passed through a pressurized chamber in a state just before solidification or assimilation, the yarn is introduced into the pressurized chamber. Since sealing at the mouth is virtually impossible, the pressure inside the pressurizing chamber is only about 0.7 kg/cJG at most, and the purpose of directly cooling the spun yarn from the mouth in a pressurized atmosphere is achieved. Can not.

In addition, in the present invention, in order to stably spin irregular cross-section fibers with excellent uniformity and strength and elongation characteristics, the jet outlet provided at the bottom of the pressurizing chamber substantially prevents the pressurized gas from blowing out. Seal as much as possible and inside the pressurized chamber 1. Oko/a (maintaining a pressurized state of G or more, and leading the mM cooled and solidified in the pressurizing chamber to the outside of the pressurizing chamber from the yarn outlet by a take-up means provided outside the pressurizing chamber. A method of ejecting fibers from a pressurized chamber by ejecting them together with high-speed pressurized gas without using a taking means outside the pressurized chamber (Japanese Patent Publication No. 47-82180 and Japanese Patent Publication No. 47
-88786 Publication), the spinning speed when fibers are drawn out at high speed.

Since it is difficult to control conditions such as spinning tension, it is difficult to stably spin fibers with excellent uniformity under certain conditions.

Next, a description will be given with reference to FIG. 1, which schematically shows a typical apparatus used when carrying out the method of the present invention.

In this device, a cylindrical pressurizing chamber 5 is formed directly below the spinneret 1, and an annular chimney 3 is provided above the pressurizing chamber 5.

A filter 4, typically a cylindrical porous filter, is provided on the inner periphery of the annular chimney 3, and the pressurized gas 6 sent into the annular chimney 3 passes through the filter 4 into a pressurizing chamber. 5, uniformly in the longitudinal and circumferential directions. The inside of the pressurizing chamber 5 includes a regulating valve provided at the inflow lower, an outlet 9 and/or an outlet at the upper part of the pressurizing chamber.
Alternatively, by adjusting the amount of gas flowing into the pressurizing chamber 5 and the amount of gas releasing to the normal pressure part outside the pressurizing chamber 5 using a regulating valve provided at the outlet 9' at the bottom of the pressurizing chamber. , is controlled to a predetermined pressure, and the pressure is detected by a pressure gauge 8.

Here, it is more effective to provide the gas outlet in the upper part of the pressurizing chamber than in the lower part of the pressurizing chamber. That is, base 1
The atmospheric temperature in the pressurized chamber immediately below is heated by heat exchange with the high-temperature yarn immediately after being discharged from the spinneret and by radiant heat from heating elements such as the spinneret 1 and the spinning device, making it higher than other parts of the pressurizing chamber. It becomes high temperature. In particular, when the single-hole discharge rate is large, the temperature becomes quite high by the time the gas reaches a position near the gas outlet 9 in the upper part of the pressurizing chamber. If such high-temperature gas accompanies the spun yarn, it will inhibit the cooling effect on the yarn surface, so a gas outlet is provided at the top of the pressurizing chamber to quickly discharge the high-temperature gas and prevent the spun yarn from cooling. If the fresh gas flowing in from the annular chimney 3 is allowed to flow directly under the spinneret surface, the cooling effect of the spun yarn can be further enhanced.

Further, in the lower part of the pressurizing chamber 5, there is a yarn outlet provided with a sealing portion +410 having a sealing function capable of substantially closing the ejection of pressurized gas. This sealing member 10 has a minute gap (square, circular, etc.) through which the yarn can pass, and the excessive flow resistance of the fluid in this gap substantially blocks the ejection and inflow of gas. A seal guide capable of maintaining the pressure state within the pressurized chamber is generally used.

As described above, since the yarn outlet is provided with the sealing member 10 that can lead out the yarn in a substantially unrestricted state, the yarn cooled in the pressurizing chamber is released from the pressurizing chamber gas. By means of a take-off means (take-off rollers 12, 13) outside the pressurized chamber, it can be taken in a substantially pressure-sealed state to the ambient atmospheric pressure section. Furthermore, since only a small amount of fluid leaks from the sealing member 10, the inside of the pressurizing chamber 5 is placed under a sufficiently pressurized condition from the upper end directly below the spinneret 1 to the lower end.

The molten thermoplastic polymer melted by an extruder (not shown) is directly spun from the spinneret 1 into the pressurizing chamber 5 as yarn Y, and the formed yarn Y runs inside the pressurizing chamber 5. During this time, it is cooled and solidified. The cooled yarn is passed from the sealing member 10 at the lower part of the pressurizing chamber 5 to the take-up rollers 12 and 1 of the outside air normal pressure section in a normal state without being substantially accompanied by pressurized jet airflow.
3, it is taken out of the pressurizing chamber 5, during which time it is applied with oil by the oil supply device 11, and is wound up by the winder 14.

Here, air is usually used as the pressurized gas 6, but a gas inert or active to the polymer, such as nitrogen gas or water vapor, can also be used depending on the purpose.

By injecting pressurized gas, the inside of the pressurized chamber becomes H,6kg/cd tj or more compared to the normal pressure part of outside air, especially 2,Ok
It is important to maintain a high pressure state of g/c++l 0 or more in order to achieve the purpose of the present invention. The pressure inside the pressurized chamber is 1
,0s/c! If it is less than □, the cooling of the spun yarn will not be sufficiently promoted, and it will be difficult to obtain irregular cross-section fibers having the desired degree of irregularity.

In addition, the cooling and solidification of yarn Y? In order to further promote the cooling effect, the outer wall of the pressurizing chamber 5 may be cooled as necessary to improve the cooling effect. Direct cooling, heat vibrator or other means? May be used.

□Also, an air flow blowing section separate from the annular chimney 3 shown in FIG. 1 is provided to supply the same type of pressurized gas or a different type of gas. It is also possible to blow out the gas into the pressurized chamber, but the gas blown out from this air flow outlet must be balanced with the pressurized gas blown in from the annular chimney so that the pressure inside the pressurized chamber is maintained at a predetermined pressure. is necessary.

In FIG. 1, the yarn Y is once taken up by the take-up rollers
The yarn is wound after relaxing the spinning tension, but it is also possible to wind it directly onto a winder without passing through a take-up roller, or it can be wound directly onto a take-up roller after being stretched in two or more stages. It is also possible to employ all the spinning and drawing methods. In particular, in order to form a uniform yarn all over, it is preferable to provide at least one take-up roller before winding up, in order to cut down the influence of spinning tension during winding.

The lubricant can be applied at any position after the yarn Y has been cooled and solidified, for example, in the normal pressure part of the outside air after leaving the pressurizing chamber as shown in Fig. It may be under pressure in a pressure chamber. In general, the seal guide 10 may be provided with a function of applying a lubricant, and the yarn may be lubricated by the seal guide 1o. As the oil supply device 11 used for applying the oil agent, a guide oil supply device is preferable in high-speed spinning of 8,000'/G or more, but a roller oil supply device other than this may be used. Further, if necessary, a heating cylinder 2 can be provided above the annular chimney 3.

Thermoplastic polymers to which the present invention can be applied include polyamides such as poly-ε-capramide and polyhexamelysine adivamide, polyesters such as polyethylene terephthalate and polytetramethylene terephthalate, polyethylene, polypropylene, etc. polyolefins and polyvinylidene fluoride, polyvinyl chloride, polyW
These are ordinary melt-spun thermoplastic polymers such as vinylidene dihydride and polyacetal, each containing two or more types of copolymerized polymers and mixed polymers. In particular, when the present invention is fully applied to polyhexamethylene adipamide, etc., which has a low melt viscosity and is difficult to increase the degree of cross-sectional irregularity, great effects can be exhibited.

〔Example〕

Examples below? The present invention will be explained in detail below. In addition, in the present invention, the degree of cross-sectional deformation (M) of the fiber is the third
In the case of a multilobal cross-sectional fiber as shown in (a)/0 in the figure (which shows a cross-sectional view of a single fiber), the radius of the circle inscribed in the cross-sectional shape of the fiber is r, and the radius of the circumscribed circle is R) -1 or R/- value. Incidentally, in the case of fiber cross sections of other shapes, the degree of cross-sectional deformation can be measured by the following method. That is, in the case of a U-shaped cross section as shown in Figure 3 (c), the radius of the circle circumscribing the cross-sectional shape is R, the radius of the circle inscribed in the bottom shape of the U shape is r, and the value of /r is Let be the degree of cross-sectional deformation.

In addition, in the case of a hollow type cross section as shown in Figure 3 (d), S/S-
Let the value of J be the degree of cross-sectional deformation.

Further, in the case of a rust-shaped cross section as shown in FIG. 3(e), the thickness of the cross section is fta, the length is b, and the value of b/ is the degree of cross-sectional deformation.

- Example 1 Sulfuric acid relative viscosity 2 in which 0.022 wt% titanium oxide was dispersed
Polyhexamethylene adipamide No. 78 was melted at 295°C, and the slit width (w) O, Q 7 ytH and the slit length (e) t were prepared by melting polyhexamethylene adipamide No.
oom, deformation degree of mouth hole ('/W) -14.8, number of holes 1
Figure 1 from a 7-hole Y-shaped cross-section cap.

It is spun into a pressurizing chamber with a structure as shown in FIG.
It was taken up at a speed of 111/min and wound up on a winder. In addition,
A water-based emulsion finishing agent was applied as a spinning oil.

The pressure inside the pressurized chamber is 1.5 ka/atG or 5.0 ka/atG.
k (1/a+fG, and the pressurized gas supplied from the annular chimney is air at 25°C, 30ONA
The inflow was carried out at a dose of 1/min and exhausted through the outflow valve.

As a comparative example, (1) When the pressure in the pressurized chamber is 0.7 ko/ciG (
No. 4), (2) Maintain the pressure inside the pressurized chamber at 5.0 ka/cfflG,
If the outflow valve is closed and the exhaust is not performed (No. 7), (
3) Remove the cylindrical pressurizing chamber part below the annular chimney from the device shown in Figure 1, install a normal duct in its place, and set the inside of the duct at normal pressure to supply cold FiIm from the annular chimney at 30ONf/ (No. 1), (4) As in the case (3) above, a normal pressure duct is used instead of the pressurized chamber, and the slit 1 to 0.07 W + m in width with a large degree of deformation of the mouth hole is used. , slit length 2.00 mm, nozzle hole deformation degree 28.6 > When using a nozzle (No, 2), (5) As in the case of (3) above, using a normal pressure duct instead of the pressurizing chamber, In each case, the cooling air volume from the annular chimney was set to 150 ON2/min, and the other conditions were the same as in the previous example.

The results obtained are shown in Table 1.

As is clear from the results in Table 1, the irregular cross-section fiber [(No, 1.4) obtained by the conventional normal pressure spinning method and the pressure spinning method with less than Iko/a+f has a low degree of cross-sectional irregularity, and The temperature characteristics are also inferior. In addition, when using the normal pressure spinning method, if the degree of deformation of the spinneret hole is increased (No, 2) or the cooling air volume is increased (No, 3), the degree of cross-sectional irregularity increases, but yarn unevenness becomes large. The strength and elongation properties are also inferior.

On the other hand, the irregular cross-sectional fibers (N O, 5, 6) obtained by the pressure spinning method of the present invention at 1 kO 10 + fG or more have a higher degree of cross-sectional irregularity than the conventional atmospheric pressure spinning method, and are uniform. It had excellent properties of strength, strength and elongation.

However, even when pressure spinning is 1kc+/ff1G or more, if the gas in the pressurized chamber is not discharged (No. 7), the precipitation of sublimated substances such as monomers and oligomers in the pressurized chamber is significant, and the As the temperature rose over time, the cooling efficiency decreased, and spinning became impossible in a short period of time.

・Example 2 A nylon 6 polymer with a sulfuric acid relative viscosity of 2.62 in which 0.3% titanium oxide was dispersed was used, except that it was melted at 265°C.
Spinning was carried out under the same conditions as in Example 1. The results are shown in Table 2. As is clear from Table 2, 1kQ/c of the present invention
Irregular cross-section fiber (N
o, 12.13) had an extremely high degree of cross-sectional irregularity compared to conventional pressure spinning methods, and had excellent uniformity and strength and elongation properties.

〔Effect of the invention〕

The irregular cross-section fiber obtained by the method of the present invention has a higher degree of cross-sectional irregularity than that obtained by the conventional melt spinning method, and has excellent uniformity and strength and elongation properties. Although the reason for such an effect is not clear, in the present invention, the pressurized chamber 5 from directly below the spinneret 1 to the yarn outlet (seal guide 10)
Since the density of the pressurized cooling gas inside the pressurized chamber is several times higher than that at normal pressure, heat exchange on the yarn surface increases, and the spun yarn is kept inside the pressurized chamber. The gas resistance force during passing increases, the entrained airflow decreases, and the heat exchange with the cooling gas is performed efficiently, promoting the cooling effect, so that the discharged polymer stream is quickly cooled and solidified. This is thought to be due to the fact that a high degree of cross-sectional deformation can be maintained. Since the cooling effect is promoted in this way, even a polymer with a low melt viscosity can easily be made into a modified cross-sectional fiber having a high degree of cross-sectional irregularity.

Furthermore, due to the increase in the gas resistance force, the degree of orientation of the yarn increases, and high strength and elongation characteristics are obtained.
: Since it can be made smaller, the disturbance (swaying, vibration) of the yarn can be suppressed to a minimum and high uniformity can be obtained.

Further, the gas used for cooling in the pressurized chamber 5 is discharged from the outlet 9.
9'i, the sublimated substances such as monomers, oligomers, catalysts, etc. generated from the discharged polymer stream are discharged to the outside together with the gas, thereby preventing the sublimated substances from being deposited into the pressurized chamber.

Furthermore, in the present invention, the yarn is taken up from a pressure chamber sealed by the sealing member 10 so as to substantially prevent the pressurized gas from blowing out at the yarn outlet, and a take-up roller controlled at a constant speed;
Since it is drawn out by a take-up means such as a winder, the pressure chamber 5
The spinning speed, spinning tension, etc. can be controlled to a constant value by these take-up means independently of the pressure state inside the chamber and the supply air volume of the pressurized gas 6. As a result, the uniformity 2
It is possible to stably spin fibers with excellent strength and elongation properties.

As described above, according to the present invention, the degree of cross-sectional irregularity can be reduced without increasing the degree of deformation of the spinneret hole or using special spinning conditions such as extremely rapid cooling of the discharged polymer flow directly under the spinneret. This makes it possible to stably obtain irregular cross-section fibers with a large cross-section and excellent uniformity and strength and elongation properties.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a typical apparatus used in the method of the present invention. FIG. 2 is a schematic diagram showing an example of the shape of a spinneret hole of a conventionally used irregular cross-section spinneret. Moreover, FIG. 3 shows an irregular cross section 4i! It is a schematic diagram showing the cross-sectional shape of [. 1: Spinneret 2: Heating cylinder 3: Annular chimney 4: Filter 5: Pressurizing chamber 6: Pressurized gas 7: Inlet 8: Pressure gauge 9.9': Outlet 10: Seal member (seal guide) 11: Lubricating device 12, 13: Take-up roller 14: Winding machine Y: Spun yarn patent applicant Toshi Co., Ltd.
LOI (c) (two)
(E) (E) (G) (U-)
(su) (nu) (ru) (wo)
(17) f, +7) Figure 2

Claims (1)

[Claims] In a method of spinning a molten thermoplastic polymer from a spinneret for irregular cross-section fibers, cooling and solidifying the spun yarn to obtain irregular cross-section fibers, a method is provided in which: 1.
The molten thermoplastic polymer is directly spun into a pressurized chamber that is maintained under high pressure conditions of 0 kg/cm^2G or more and has a gas inlet and an outlet, and the spun yarn is cooled in the pressurized chamber. After solidification, the cooled yarn is transferred to normal pressure from a sealed yarn outlet provided at the bottom of the pressurizing chamber so as to substantially prevent the pressurized gas from blowing out, by means of a take-up means outside the pressurizing chamber. 1. A method for melt-spinning fibers with irregular cross-sections, the method comprising drawing and drawing fibers into sections.