JPH10331025A - Spinneret for core-sheath conjugated fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spinneret capable of affording a core-sheath type conjugated fiber at various core-sheath conjugated ratios without any eccentricity with good operating efficiency for a long period by using two different thermoplastic polymers. SOLUTION: This spinneret for a core-sheath conjugated fiber comprises an upper spinneret plate 1 and a lower spinneret plate 2, the lower spinneret plate 2 having a discharge lead-in hole 5 for a sheath component polymer in the upper part thereof and a lead-in hole 10 for a conjugated polymer and a spinning hole 12 in the lower part in the spinneret for obtaining the core- sheath conjugated fiber containing the two different kinds of thermoplastic polymers arranged in the core sheath shape. The upper spinneret plate 1 has a capillary 7 for the core-component polymer and an introduction hole 4 for the sheath-component polymer. The lower part of the capillary 7 is inserted along the inner wall of the discharge lead-in hole 5 and a helical groove 8 to be a channel for the sheath component polymer is provided from the upper to the lower parts in the outer peripheral part 11 of the capillary 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a spinneret for obtaining a core-sheath conjugate fiber using two kinds of different thermoplastic polymers arranged in a core-sheath shape and having no eccentric core.

[0002]

2. Description of the Related Art Many core-sheath composite fibers in which two or more different polymers are arranged in a core-sheath shape have been developed and manufactured.
Examples of such a core-sheath composite fiber include a core-sheath composite fiber having a high melting point polypropylene or polyethylene terephthalate as a core component and a low melting point polyethylene as a sheath component. Such a core-sheath conjugate fiber can be easily fused with each other by a low melting point polyethylene as a sheath component by a heat fusion method, and the core component polypropylene or polyethylene terephthalate can maintain strength. Therefore, a high-strength nonwoven fabric can be easily manufactured.

[0003] In order to obtain a higher quality product using such a core-sheath composite fiber, a core-sheath composite fiber having no eccentricity of the core is required. Various spinnerets for obtaining fibers have been proposed.

Conventionally, a capillary serving as a flow path of a core component polymer is inserted along the inner wall of a discharge guide hole for discharging a sheath component polymer, and the core component polymer discharged from the capillary and the outer periphery of the capillary in the discharge guide hole. The sheath component polymer discharged through the hole becomes a composite polymer below the discharge guide hole, and a spinneret spun from the spinning hole is used.

However, in this spinneret, the core component polymer discharged from the capillary and the sheath component polymer simply discharged through the outer periphery of the capillary are bonded below the discharge guide hole to form a core-sheath composite fiber. Therefore, the core-sheath type composite fiber without eccentricity could not be obtained unless the working accuracy of the capillary fitted along the inner wall of the discharge guide hole was extremely high.

Therefore, Japanese Patent Application Laid-Open No. 57-171711 discloses an upper die plate provided with holes for introducing a core component polymer and a plurality of sheath component polymers, and a lower die plate for introducing a core component polymer and a sheath component polymer. A spinneret has been proposed in which a composite polymer introduction hole for introducing both is provided, and a metal sintered body is fitted around the composite polymer introduction hole. According to this spinneret, the core component polymer flows down through the introduction hole of the upper die plate and is introduced straight into the composite polymer introduction hole, and the sheath component polymer flows down through the plurality of introduction holes of the upper die plate to form the composite polymer. It penetrates into the metal sintered body around the introduction hole. The sheath component polymer is uniformly leached out from the inner peripheral surface of the sintered metal body and covers the periphery of the core component polymer introduced into the polymer introduction hole with a uniform thickness, so that there is no eccentric core-sheath type composite. Fiber is obtained.

This spinneret solves the above-mentioned drawbacks of the conventional spinneret.
Although it is possible to obtain a core-sheath type composite fiber without eccentricity, foreign matter in the polymer is clogged in the metal sintered body, and the smooth flow of the sheath component polymer is hindered. There is a problem that the core-sheath type conjugate fiber is obtained and that only a conjugate fiber having a low core ratio can be stably manufactured.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and can be composited at various core-sheath composite ratios by using two kinds of different thermoplastic polymers. An object of the present invention is to provide a spinneret capable of obtaining a long core-sheath type composite fiber with good operability for a long time.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and have reached the present invention. That is, the present invention relates to a spinneret for obtaining a core-in-sheath composite fiber in which two kinds of thermoplastic polymers are arranged in a core-in-sheath shape. A lower die plate having a guiding hole and a spinning hole, and an upper die plate provided with a capillary for the core component polymer and a guide hole for the sheath component polymer, and the lower portion of the capillary extends along the inner wall of the discharge guiding hole. The inserted core component polymer discharged from the capillary guide hole of the capillary and the sheath component polymer discharged from the guide hole through the outer periphery of the capillary of the discharge guide hole become a composite polymer in the guide hole, and the spinning hole A spinneret to be spun more, wherein a spiral groove serving as a flow path of a sheath component polymer is provided on an outer peripheral portion of the capillary from above to below. That the core-sheath composite fiber spinneret for it is an gist.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view (without cutting a capillary) showing an embodiment of the spinneret for a core-sheath composite fiber of the present invention.
FIG. 2A is a partially enlarged schematic view showing the shape of a spiral groove in the spinneret of FIG. 1, and FIGS. 2B and 2C are spiral diagrams of the spinneret for the core-sheath conjugate fiber of the present invention. It is a mimetic diagram showing other embodiments of a shape groove.

The thermoplastic polymer to be spun using the spinneret of the present invention is not particularly limited as long as it is a polymer that can be melt-spun. For example, polyesters such as polyethylene terephthalate and polybutylene terephthalate; Examples include olefins such as polyethylene and polypropylene, polyamides such as nylon 6 and nylon 66, and copolymers and mixtures containing these as main components. Examples of different types of polymers include polymers having different copolymer components and mixed components in addition to polymers having different types of polymers.

The spinneret of the present invention is a spinneret for obtaining a core-sheath composite fiber in which two kinds of thermoplastic polymers are arranged in a core-sheath shape, and comprises an upper die plate 1 and a lower die plate 2. . The lower die plate 2 has a discharge guide hole 5 for the sheath component polymer at the upper part, a guide hole 10 for the composite polymer and a spinning hole at the lower part.
The upper die plate 1 has a capillary 7 for a core component polymer and a guide hole 3 for a sheath component polymer, and a lower portion of the capillary 7 is inserted along the inner wall of the discharge guide hole 5. Have been.

The spinneret of the present invention comprises a core component polymer discharged from the capillary guide hole 6 of the capillary 7 and a sheath discharged from the guide hole 3 through the outer peripheral portion 11 of the capillary 7 of the discharge guide hole 5. The component polymer becomes a composite polymer in the guide hole 10 and is spun from the spinning hole 12, and a spiral groove 8 serving as a flow path of the sheath component polymer is formed on the outer peripheral portion 11 of the capillary 7 from above to below. It is provided toward.

Next, the flow of the polymer in the spinneret of the present invention will be described. First, the core component polymer is the upper die plate 1
The sheath component polymer is introduced from the capillary guide hole 6 of the capillary 7 through the guide hole 3 of the upper die plate.

Then, the core component polymer flows down through the capillary guide hole 6 and is discharged from the capillary discharge hole 9 at the bottom into the guide hole 10. On the other hand, the sheath component polymer is the guide hole 3
When the liquid is introduced from the introduction hole 4 through the passage, it is discharged into the guide hole 10 through the inside of the discharge guide hole 5 through the outer periphery of the capillary 6.

At this time, when the sheath component polymer is discharged through the outer periphery of the capillary 6, the polymer flowing down along the spiral groove 8 and the polymer flowing vertically out of the spiral groove 8 are separated from the spiral groove 8. It is discharged into the guide hole 10 as a polymer flow having two types of flows. Since the sheath component polymer of these two flows flows along the outer peripheral portion 11 of the capillary 6, a sheath layer having a uniform thickness is formed, and the sheath component polymer causes the sheath component polymer to flow downward from the capillary discharge hole 9 at the bottom of the capillary. The discharged core component polymer is wrapped, and a composite fiber without eccentricity wrapped in a uniform sheath layer can be obtained.

As described above, according to the spinneret for the core-sheath conjugate fiber of the present invention, the sheath component polymer and the core component polymer flow as described above, whereby the core component polymer is wrapped in a uniform sheath layer. Since the fibers can be obtained, even if there is some variation in the machining accuracy when the capillary 7 is inserted along the inner wall of the discharge guide hole 5, it is possible to easily obtain the core-sheath type composite fiber without eccentricity. it can.

Further, by changing the flow rate of the sheath component polymer and the groove width of the spiral groove 8, for example, even when the ratio of the sheath portion is low, the thickness of the sheath portion is uniform, and the core component polymer is formed. Even when conjugated at various core-sheath conjugate ratios, such as a conjugate fiber wrapped well, core-sheath type conjugate fibers with no eccentricity of the core can be obtained.

The shape of the spiral groove 8 provided on the outer peripheral portion 11 of the capillary 7 is not particularly limited as long as the spiral groove 8 is provided from above to below the capillary 7. As described above, the number and the groove width may be variously changed depending on the type of the conjugate fiber to be produced and the type of the polymer to be used, as long as the effect of wrapping the core component polymer can be exhibited well.

As shown in FIG. 2B, a spiral groove 8 is formed.
It is preferable that the diameter of the capillary 7 provided with is smaller as it becomes lower than the diameter of the upper part of the capillary. This allows the polymer flowing down along the spiral groove 8 of the sheath component polymer to be better covered with the polymer flowing off the spiral groove 8 and flowing vertically.
The effect of encapsulating the core component polymer with the sheath component polymer can be further improved.

As shown in FIG. 2 (c), there is no spiral groove 8 in a part of the lower part of the capillary 7 and a part having a larger diameter than the capillary part in which the upper spiral groove 8 is provided. When provided, the flow channel becomes narrow immediately before the sheath component polymer flows into the guide hole 10, the pressure loss generated by the flow channel increases, and the meterability of the sheath component polymer can be improved. This makes it possible to obtain a conjugate fiber having a more uniform thickness of the sheath layer.

[0022]

Next, the present invention will be described in detail with reference to examples. In addition, the measuring method and evaluation of the characteristic value in an Example are as follows. [Melt viscosity (poise)] Flow tester (CFT-50, Shimadzu Corporation)
0A) at a constant temperature of 290 ° C and a shear rate of 1000
The value at the time of sec ⁻¹ was set as the measured value, and the measurement was performed three times, and the average value was shown. The sample used was dried at 120 ° C. for 5 hours in a nitrogen atmosphere. [Eccentricity of core] The cross-sectional shape of the obtained conjugate fiber was enlarged and photographed, and visually judged.

Example 1 Composite spinning was carried out using the spinneret shown in FIG. 1 having a spiral groove shape shown in FIG. 2 (b). Polyethylene terephthalate having a melt viscosity of 2000 poise (containing 0.015% by weight of magnesium stearate (StMg)) in the sheath component polymer,
The core component polymer is a polyethylene oxide crosslinked product and polyethylene terephthalate (StMg) with a melt viscosity of 500 poise.
0.015% by weight) and the core / sheath weight ratio
Melt spinning was performed at 90/10, a discharge rate of 37.4 g / min, and a spinning temperature of 290 ° C., and the film was wound at a speed of 4000 m / min. The obtained undrawn yarn was heated and drawn using a drawing roller at a temperature of 90 ° C. and a draw ratio of 1.12, and was wound at 630 m / min to obtain a fiber of 75d / 36f. In each single yarn constituting the obtained fiber, the presence or absence of eccentricity of the core portion was evaluated for the fiber after 1 hour and the fiber after 20 hours after the operation. It was a composite fiber.

[0024]

According to the spinneret for a core-sheath composite fiber of the present invention, it is possible to use two kinds of different thermoplastic polymers at various core-sheath composite ratios and to provide a core-sheath type without core eccentricity. The composite fiber can be manufactured for a long time with good operability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (without cutting a capillary) showing an embodiment of a spinneret for composite fibers of the present invention.

2 (a) is a partially enlarged schematic view showing the shape of a spiral groove in the spinneret of FIG. 1, and FIGS. 2 (b) and 2 (c).
FIG. 4 is a schematic view showing another embodiment of the spiral groove in the spinneret for a conjugate fiber of the present invention.

[Explanation of symbols]

 Reference Signs List 1 upper die plate 2 lower die plate 3 guide hole 4 introduction hole 5 discharge guide hole 6 capillary guide hole 7 capillary 8 spiral groove 9 capillary discharge hole 10 guide hole 11 outer peripheral portion 12 spinning hole

Continued on the front page (72) Inventor Sou Yamaguchi Uji Kozakura 23, Uji-city, Kyoto Prefecture Unitika Co., Ltd. Central Research Laboratory (72) Inventor Kazuaki Taruishi 23 Uji Kozakura Uji-city, Kyoto Pref. 23 Unitika Research Center Co., Ltd.

Claims (1)

[Claims] 1. A spinneret for obtaining a core-sheath conjugate fiber in which two kinds of thermoplastic polymers are arranged in a core-sheath shape,
A lower base plate having a discharge guide hole for the sheath polymer at the top, a guide hole for the composite polymer and a spinning hole at the bottom, and a capillary for the core polymer and a guide hole for the sheath polymer. It consists of a base plate, the lower part of the capillary is inserted along the inner wall of the discharge guide hole, and the core component polymer discharged from the capillary guide hole of the capillary and the outer periphery of the capillary of the discharge guide hole from the guide hole. The discharged sheath component polymer becomes a composite polymer in the guide hole, and is a spinneret spun from the spinning hole, and a spiral groove serving as a flow passage of the sheath component polymer is formed on the outer periphery of the capillary from above to below. A spinneret for a core-sheath conjugate fiber, which is provided to face.