JPS60162804A - Process for melt spinning island-in-sea type conjugate fiber - Google Patents

Abstract

PURPOSE:To obtain the titled fibers safely without causing mutual adhesion and broken yarns of an island component, by spinning the island and sea components through a spinneret for island-in-sea type conjugate fibers having plural tubular bodies for extruding the island component from the interior thereof and an annular channel for the sea component surrounding the island component at a specific flow velocity ratio. CONSTITUTION:Island-in-sea type conjugate fibers are spun by extrusion through extrusion holes 12 of a spinneret therefor of structure in which an island component (A) is introduced from introductory holes 5 into plural tubular bodies 7 and extruded into channels 10, and a sea component (B) is passed from introductory holes 15 through an annular channel 8 therefor and extruded surround respectively the island component (A). In the process, conditions are set to make the relation between the flow velocity (Y) of the island component (A) extruding from the tubular bodies 7 to the sea component (B) extruding from the annular channel 8 for the sea component (B) at a joining part 11 of both components (A) and (B) and the melt viscosity ratio (X) of the island component (A) to the sea component (B) satisfy formula I , preferably formula II. Thus, the aimed conjugate fibers are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for spinning an island-in-the-sea composite fiber with excellent spinnability.

Conventional technology and its problems Conventionally, sea-island type composite fibers, which incorporate multiple filaments that are substantially continuous in the fiber axis direction in one fiber, are known as 1.
It is effectively used as a material for synthetic leather and synthetic leather-like textile materials, and various spinning methods for producing these sea-island composite fibers have also been proposed.

The most common and excellent method is to assemble the material in a state where it is then spun.

The spinning of this sea-island type composite fiber involves combining a group of tubular bodies that are composed of at least two or more spindle plates, have a flow path for the sea component between the two upper and lower spindle plates, and introduce the island component. A base is used.

However, in such a cap, the sea-component polymer is introduced from the outer periphery of the cap toward the inner periphery (center of the cap) in the upper and lower cap plate flow channels, so it is particularly difficult to use when the cap has a large diameter. When the proportion of sea components in the fibers becomes low, a difference in residence time occurs between the polymer discharged from the outer circumference of the nozzle and the polymer discharged from the inner circumference of the nozzle.
In the inner periphery of the spinneret, the flow rate of the polymer is low and the residence time is long, so heat-denatured polymer is likely to occur, resulting in a difference in viscosity between the inner and outer circumferences of the discharged polymer, and the viscosity of the polymer in the inner periphery decreases with long spinning.

If spinning under such conditions for a long period of time, the viscosity difference between the sea component and the island component will increase, especially in the inner periphery where the viscosity of the sea component decreases, resulting in defects such as one component adhering to the other and merging, resulting in a composite flow. It is no longer possible to maintain this condition, and in some parts, holes are formed where even the discharge of the sea component is no longer recognized, and the number of spun yarn breakages increases. Therefore, the life of the die required to maintain the form of the sea-island composite fiber is extremely short, and there are drawbacks such as the need to replace the die quickly.

Object of the present invention The present invention was obtained as a result of intensive studies to improve the defects of the above-mentioned spinning method. The purpose of the present invention is to provide a method that allows stable spinning even when the ratio of components is high. When spinning a sea-island composite fiber using a spindle for sea-island composite fiber, which has an annular sea component flow path surrounding each of the island components.

The relationship between the flow velocity ratio Y of the sea component polymer and the island component polymer at the junction with the island component flowing out from the tubular body and the solution viscosity ratio X of the sea component polymer and the island component polymer satisfies the following. It is characterized by This is a method for spinning sea-island composite fibers.

However, 2 Ql′4゜S,・ρ1 where Q, :lj? Discharge amount of sea component per unit time flowing out from the shaped sea component flow path (1 piece) Q,: Discharge amount of the roaring island component per unit time flowing out from the tubular body (1 piece) SI: Annular sea component flow Cross-sectional area S of the channel (1 piece), Cross-sectional area ρ of the tubular body through which the two island components flow out, : Density ρ of the sea component polymer, : Density η of the island component polymer, : Melt viscosity η of the sea component, Two island components The melt viscosity is

The present invention will be described below with reference to the drawings, but it goes without saying that the present invention is not limited to the following embodiments. FIG. 1 is a cross-sectional view of a seabird type composite fiber mouthpiece. In FIG. The liquid flows into the interior of the tubular body 7 provided therein. On the other hand, the sea component B is the packing fK of the backing grooves 14, 14/ provided in a circular tube shape.
Completely separated from Yoshishima component A, 1 fracture 1.2 plate 2
An introductory hole 15″f, which is perforated in a circumferential manner on the outer periphery of the
It is guided to an ocean flow path 8 formed between bone plates 2 and 6 bone plates 3. Next, the liquid is metered through a slit 9 formed between the tubular body 7 and the third boat plate 6, and flows out from the inside of the tubular body 7. One core-sheath type composite flow is formed in the flow path 10 surrounding the island component A.

The composite flow is guided to a gathering part 11 provided on the four boat boards 4,
A large number of core-sheath type composite flows guided from other similarly formed channels are collected and discharged from the discharge hole 12 to form one sea-island type composite fiber.

Here, 13 is an annular ring provided in the space between the second bone plate 2 and the third bone plate 6. As described above, by uniformly arranging the tubular bodies of the sea component introduction holes and the island component introduction holes on the nine cap plates, a sea-island type composite fiber cap is constructed, but in such a cap, there is no adhesion of the island components to each other; In order to obtain a sea-island type composite fiber that is stable over a long period of time, the relationship between the melt viscosity of the sea component polymer and the melt viscosity of the island component polymer, and the annular slit 16 from which the sea component flows out in the core-sheath type composite flow forming section 10 must be determined. It has been found that the relationship between the cross-sectional area and the cross-sectional area of the outflow portion of the tubular body 7 through which the island components flow out is extremely important.

FIG. 2 is an enlarged view of the core-sheath type composite flow forming section.

FIG. 6 is a sectional view taken along the line CC/ in FIG. 2. In Figure 2, the sea component Bid tubular body 7 and the slit 9 of the hole in the No. 6 plate 3.
One core-sheath type composite flow is formed in the composite flow forming part 10 surrounding the island component A that is metered by the flow rate and flowing out from the inside of the tubular body 7. Component B
i Cross-sectional area of the annular slit 16 to be supplied Sl is the island component A
When the cross-sectional area S of the outflowing tubular body 7 is extremely large compared to S, the flow velocity ratio of the sea component polymer and the island component polymer becomes large, and the flow state of the sea component polymer and the island component polymer in the composite flow forming part becomes extremely unstable. As the discharge amount of the island component becomes larger than that of the sea component in 4G, the instability increases, and when a viscosity difference is created in the sea component due to long-time spinning, this negative effect is exacerbated. Ru. That is, if the flow velocity ratio of the sea component and the island component in the composite flow forming section 10 exceeds a certain value, the complete core-sheath type composite flow will not be formed and the
Since it is guided to the gathering part 11 of the number plate 4 and collected with a large number of composite flows led from other channels, it is impossible to spin seabird-type composite fibers stably over a long period of time due to the fact that the island components adhere to each other. This is the result. This relationship is closely related to the melt viscosity of the sea component polymer and the island component polymer, and the melt viscosity of the sea component polymer is lower than that of the island component polymer (that is, the melt viscosity fK of the island component polymer is The core-sheath composite flow becomes unstable as the ratio of the melt viscosities of the component polymers increases.

The present invention provides a long-term stable spinning technology for sea-island type composite fibers, in which the sea component flowing out from the annular sea component flow path formed between the sea component flow path lower mouth plate 6 and the tubular body 7, At the junction with the island component flowing out of the tubular body. It is characterized in that the relationship between the flow velocity ratio Y of the sea component polymer and the island component polymer and the melt viscosity ratio X of the sea component polymer and the island component polymer satisfies x X .

This makes it possible to reliably eliminate the drawbacks seen in conventional methods and to stably obtain high quality sea-island composite fibers.

Effects of the present invention The effects of the present invention will be explained in more detail below based on Examples.

Example Polyethylene terephthalate with a melt viscosity of 1,500 poise to 5,000 poise (measured with a descending flow tester at 280°0) was used as the island component, and a melt viscosity of 500 poise to 5,000 poise as the sea component (same measurement conditions as the island component). Using polystyrene of Spinning was carried out by

The basic conditions for spinning are as follows.

No. 4 plate nozzle number of discharge holes: 200 holes Number of islands per discharge hole: 16 Ratio of main island components: 65 Suspension spinning temperature: 280° C. Take-up speed: 1000 m/min The spinning results are shown in FIG. 4. As can be seen from the figure, in the present invention, it is possible to perform spinning stably for an extremely long period of time, and excellent effects such as an improvement in the spinning yield and a reduction in the number of pieces required per spinneret can be exhibited.

In addition, in FIG. 4, each mark indicates the following lifespan of the cap.

◎ indicates the lifespan of the cap is 40 days or more ○ indicates the lifespan of the cap from 25 to 39 days. Δ mark indicates the lifespan of the cap 10 to 24 days. The x mark means the lifespan of the cap is 9 days or less.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a sea-island type composite fiber die. Figure 2 is a partially enlarged view of the core-sheath type composite flow forming part, Figure 6 is a cross-sectional view taken along the line CC/ in Figure 2, and Figure 4 is the flow velocity of island component polymer and sea component polymer flow velocity in the composite flow forming part. FIG. 3 is a diagram showing the relationship between the ratio of the island component polymer viscosity to the sea component polymer viscosity, and the life of the mouthpiece. 1.2.3.4: Base plate 5, 15: Introduction hole <S, 1
2: Discharge hole 7: Tubular body 8: Sea flow path 9.16: Slit 10: Channel 11: Gathering portion 13: Annular ring 14, 14/: Packing groove S1
: Cross-sectional area S of the sea component flow path, : Cross-sectional area of the island component flow path Patent applicant Toshi Co., Ltd.

Claims (1)

[Scope of Claims] A sea-island type ferrule for a sea-island type composite fiber, in which island components flow out from the inside of a plurality of tubular bodies, and an annular sea component flow path is provided to surround each of these island components. When spinning a composite fiber, the flow velocity ratio Y of the sea component polymer and the island component polymer at the joint between the sea component flowing out from the annular sea component flow path and the island component flowing out from the tubular body, and the sea component A method for spinning a sea-island composite fiber, characterized in that the relationship between the melt viscosity ratio X of the polymer and the island component polymer satisfies a linear equation.