JP2020165026A - Spinneret for sea-island type conjugate fiber - Google Patents

Abstract

To provide a spinneret for a sea-island type conjugate fiber suitable for manufacturing an ultrafine fiber.SOLUTION: In a spinneret for melt-spinning a sea-island type conjugate fiber group in which a large number of island component polymers in a mutually separated state are independently present in an extended state within a sea component polymer along a fiber axis direction in one single fiber, a composite flow formed of a core made of the island component polymer component and a sheath made of the sea component polymer is gradually made thin inside one extrusion hole as two or more single flows and spinned.SELECTED DRAWING: Figure 1

Description

The present invention relates to a spinneret for a sea-island type composite fiber suitable for producing an ultrafine fiber bundle.

Conventionally, when one single fiber (filament) constituting a thread is taken out, a plurality of island component polymers substantially continuous in the fiber axis direction are contained in the sea component polymer constituting this single fiber. The "sea-island type composite fiber" that has existed independently is known. Such sea-island type composite fibers are widely used as constituent materials for non-woven fabrics and woven fabrics because ultrafine fiber bundles composed of island components can be obtained by removing only the sea components after spinning. In particular, it is useful as a leather-like sheet material for artificial leather, artificial leather-like woven fabric, and the like.

Further, the ultrafine fiber bundle can produce many useful products having new characteristics, not limited to the above materials, and further expands the use of synthetic fibers in various industrial applications and fashion fields. Therefore, various spinning caps have been proposed for melt-spinning these sea-island type composite fibers.

For example, Patent Document 1 proposes a mouthpiece for composite spinning of a multifilament yarn composed of a sea-island type composite single fiber group in which the number of pipes (tubular bodies) for introducing the island component polymer into the sea component polymer is increased. ing. Certainly, according to this method, by increasing the number of pipes for introducing the island component polymer, a sea-island type composite single fiber having 100 islands or 1000 islands in one single fiber (filament). But it can be spun.

However, in Patent Document 1, although ultrafine fibers can be obtained by increasing the number of pipes into which the island component is introduced to realize ultra-multi-islandization, cross-sectional formation of sea-island composite fibers is carried out with the multi-islandization. There is a problem that it becomes difficult. On the other hand, especially when trying to produce a sea-island type composite fiber having an island diameter of several tens to 400 nm, the fiber diameter per sea-island type composite fiber becomes small, which causes thread breakage. It was difficult to make it stably.

Further, Patent Document 2 proposes a sea-island type composite fiber spinning mouthpiece in which an entry flow path of the sea-component polymer is formed so that the island-component polymers do not bond to each other. However, in Patent Document 2, there is a problem that it becomes mechanically difficult to densely arrange the pipes through which the island components flow in order to form the ingress flow path of the sea component polymer.

On the other hand, in recent years, even in ultrafine fibers, the demand for ultrafine fibers having nano-order yarn diameters has increased due to their unique texture and unique functionality due to the large surface area of yarns. It is desired to solve these problems in order to stably industrially produce sea-island type composite single fibers having an island diameter of 10 to 400 nm.

JP-A-2010-203003 JP-A-2009-911680

The present invention has been made in view of the above background, and an object of the present invention is a sea-island type composite fiber spinning base suitable for producing ultrafine fibers (particularly, a fiber diameter of 400 nm or less), a sea-island type composite fiber produced from the mouthpiece, and a sea-island type composite fiber. It is an object of the present invention to provide ultrafine fibers having a flat cross-sectional shape.

As a result of diligent studies to solve the above problems, the present inventor has made two or more core-sheath composite flow groups into one integrated flow in one discharge hole in the conventional spinneret for sea-island type composite fibers. We have found that the above problems can be solved when spinning while gradually reducing the size, and have completed the present invention.

That is, according to the present invention
1. 1. A spinneret for melt-spinning a group of sea-island type composite fibers in which a large number of island-component polymers are separated from each other in one single fiber and extend independently in the sea-component polymer along the fiber axis direction. And
The spinneret is
(A) A tubular body group (4) that divides the island component polymer into a plurality of polymer trickles, respectively.
(B) A distribution chamber (10) in which the tubular body group (4) is projected inside and the sea component polymer is internally distributed so as to surround each of the tubular body groups (4).
(C) Each island component polymer is bored directly under the distribution chamber (10) in a one-to-one correspondence with each of the tubular body groups (4) and supplied from the tubular body group (4). , A confluence hole group (6) that flows down while forming a core-sheath complex flow group corresponding to the number of tubular body groups (4) by merging with the sea component polymer supplied to the distribution chamber (10).
(D) An introduction hole having a funnel shape is formed above, in which two or more core-sheath composite flow groups flowing in from each lower end of the confluence hole group (6) are aggregated to form an integrated flow. A discharge hole that is spun after guiding the integrated flow downward while gradually reducing it.
Spinning caps for Kaijima-type composite fibers, characterized by having
Is provided.

And in the present invention
2. The spinneret for a sea-island type composite fiber according to 1 above, wherein the inner diameter Di of the tubular body and its wall thickness t satisfy the following formula (a).
0.05 ≦ (t / Di) ≦ 0.35 (a)
Is preferable.

Further, in the present invention,
3. 3. The spinneret for a sea-island type composite fiber according to 1 or 2 above, wherein the outer diameter Do of the tubular body and the diameter d of the introduction portion of the confluence hole satisfy the following formula (b).
0.85 ≤ (d / Do) ≤ 2.0 (b)
Is preferable.

Further, in the present invention,
4. The most distance between the outer diameter Do of the tubular body and the outer edge of the funnel-shaped introduction hole, which is a combination of two or more core-sheath composite flow groups to form an integrated flow, and the core-sheath flow group. The spinneret for a sea-island type composite fiber according to any one of 1 to 3 above, wherein a small distance satisfies the following formula (c) with Dr.
Do ≤ Dr ≤ 5 Do (c)
Is preferable.

According to the present invention, an ultra-multi-island sea-island type composite fiber can be produced by aggregating two or more core-sheath composite flows and spinning them as an integrated flow. Therefore, the fineness is ultra-fine and uniform, and the island components It is possible to obtain ultrafine fibers having a flat cross section and having extremely high quality without joining.

Further, since the sea-island type composite fiber using the above-mentioned mouthpiece has two or more core-sheath composite flow groups assembled, the island shape has a flat cross section. After that, by reducing the weight of the sea polymer, ultrafine fibers having a flat cross-sectional shape can be produced.

It is sectional drawing which illustrates an example of the mouthpiece for sea island type composite fiber spinning of this invention.

Hereinafter, the present invention will be described in detail.

In the present invention, the island component polymer A is not particularly limited, but for example, polyethylene terephthalate and its copolymer, polyethylene naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, polypropylene, polyolefin, polycarbonate, polyacrylate. , Polyamide, polylactic acid and other melt-moldable polymers can be preferably exemplified.

At that time, various additives such as titanium oxide, silica, inorganic substances such as barium oxide, carbon black, colorants such as dyes and pigments, flame retardants, fluorescent whitening agents, antioxidants, and ultraviolet absorbers are added to the polymer. May be included in.

Examples of the sea component polymer B include polymers capable of melt molding of copolymerized polyethylene terephthalate, polyamide, polystyrene and its copolymers, polyethylene, polyvinyl alcohol and the like, and which can be dissolved and extracted after spinning.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Here, FIG. 1 is a cross-sectional view illustrating an example of the sea-island type composite fiber spinning base of the present invention. Note that FIG. 1 exemplifies only one discharge hole unit provided in the base for spinning a sea-island type composite single fiber which is one filament, but in general, a large number of these units are provided in the base. It is a well-known fact that multifilament yarns provided and composed of a large number of sea-island type composite single fiber groups are spun.

Further, in FIG. 1, polymer distribution channels are provided on the upstream side of the three illustrated base plates, but these distribution channels are design items that can be easily implemented as appropriate. Since it is not a feature of the present invention, the illustration is omitted.

In the embodiment of the spinneret according to the present invention illustrated in FIG. 1, reference numerals A and B in the drawings represent island component polymers and sea component polymers, respectively, and these island component polymers A and sea component polymers B are , Each flow into the base plate from the direction of the arrow in the figure. As a matter of course, the island component polymer A and the sea component polymer B flowing in the spinneret pack, or a composite flow thereof, maintains an extremely stable laminar flow state.

Therefore, the streamlines formed by these polymer streams do not intersect or cross each other, unlike turbulence. Therefore, it goes without saying that composite fibers such as sea-island type composite fibers, core-sheath type composite fibers, and side-by-side type composite fibers are stably formed, and melt spinning of the composite fibers can be carried out.

Next, reference numerals 1, 2 and 3 in FIG. 1 form three base plates in this embodiment, from the upper base plate 1, the middle base plate 2, and the lower base plate 3, respectively. It is configured.

However, there is no particular reason to limit the group of base plates to three as in this example, and the number can be increased if necessary. Further, reference numeral 4 is a tubular body group, reference numeral 5 is a sea component introduction hole, reference numeral 6 is a merging hole group, reference numeral 7 is a discharge hole, reference numeral 8 is a distribution chamber of island component polymer A, and reference numeral 9 is. The introduction channel of the sea component polymer B and the reference numeral 10 indicate the distribution chamber of the sea component polymer B, respectively.

Here, the polymer flow path for the one unit bored in the upper metal plate 1 will be described. First, a distribution chamber 8 of the island component polymer A is provided above the central portion of the unit from the upper end to the downstream side thereof as illustrated in FIG. 1, and a large number of tubular body groups 4 are provided in the distribution chamber 8. It is planted from the bottom to near the lower end of the upper metal plate 1. The tubular body group 4 is projected into the distribution chamber 10 of the sea component polymer B formed from the lower end of the upper mouthpiece plate 1 toward the upstream side, and the sea component polymer B is distributed. The structure is such that the sea polymer B is supplied to the chamber 10 via the introduction flow path 9.

Next, the polymer flow path for the one unit bored in the middle metal plate 2 will be described. The middle metal plate 2 is provided with a through hole group composed of a merging hole group 6 in a one-to-one correspondence with each of a large number of tubular body groups 4 planted in the upper metal plate 1. The sea component polymer B supplied to 10 and the island component polymer A supplied from the tubular body group 4 projecting into the distribution chamber 10 form a core-sheath composite flow and pass through. To briefly supplement this core-sheath composite flow, the sea component polymer B supplied to the distribution chamber 10 forms a sheath portion and flows so as to surround the tubular body group 4, so that each tubular body group The island component polymer A supplied from each of No. 4 forms the core portion of the core-sheath composite flow.

Finally, the polymer flow path for the one unit bored in the lower cap plate 3 will be described. As illustrated in FIG. 1, the lower mouthpiece 3 is provided with a discharge hole 7 having a funnel-shaped introduction portion, and two or more of the core-sheath composite flows merge into the discharge hole 7. The ultra-multi-island sea-island composite monofibers that flow in and coalesce with each other will be spun out.

The present application is characterized in that there are two or more flow paths of such island components and sea components in the unit, and the core-sheath composite flow is merged into one discharge hole 7 and discharged.

What has been described above is the description of the spinneret structure in which the super-multi-island sea-island composite single fiber is spun as one filament from two or more units. However, a major feature of the present invention is that a multifilament yarn composed of a super-multi-island sea-island composite single fiber group is melt-spun using a spinneret provided with a large number of units described above at the same time. ..

As can be easily understood from the above description, it can be easily understood that the core-sheath composite flow is formed by the number of tubular body groups 4 (which is also the number of confluence hole groups 6). Therefore, it can be easily understood that the more the number of 4 in the tubular body group is increased, the more multi-island can be realized. However, when the number of 4 in the tubular body group is increased too much, good sea-island composite fibers cannot be obtained due to fusion between the island polymers.

Therefore, the number of one tubular body group 4 is preferably 1500 or less, and more preferably 1000 or less. On the other hand, when making ultrafine fibers having a diameter of 400 nm or less and trying to make one tubular body group into one composite fiber, the single yarn fineness becomes thinner with the diameter of the yarn, and it becomes difficult to wind the yarn. Therefore, a spinneret structure in which ultra-multi-island sea-island composite single fibers are spun as one filament from two or more units is indispensable.

By taking various measures as described above, it is possible to design a base capable of stably spinning a multifilament composed of an ultra-multi-island sea-island type composite single fiber group. However, even with a spinneret having such characteristics, depending on the selection of the island component polymer A and the sea component polymer B, the viscosity changes depending on the viscosity, viscosity ratio, interface characteristics of the polymer, spinning temperature, and degree of drying. It was found that it may be difficult to obtain a stable sea-island type composite fiber.

Therefore, as a result of further diligent studies, the present inventor can obtain better results by optimizing the conditions for the tubular body group 4, the confluence hole group 6, and the discharge hole 7, and design a more compact spinneret. It turned out that it could be done. This point will be described in detail below.

First, the tube inner diameter Di of the tubular body 4 and its tube length L were examined. In order to ensure that the island component polymer A is evenly distributed between the tubular bodies 4, a suitable back pressure is provided on the upper part of the confluence hole 6. It needs to be designed so that pressure can be obtained. However, the values largely depend on the properties of the sea component polymer B and the island component polymer A, and in that sense, it is preferable to determine these values experimentally using the polymer actually used. However, the inner diameter Di of the tubular body 4 is preferably 0.1 mm or more from the viewpoint of preventing clogging caused by the residual polymer after spinning. However, if the inner diameter Di of the tube is too large, the number of tubular bodies 4 that can be arranged is reduced, so the upper limit thereof is preferably 0.5 mm, although it depends on the wall thickness t of the tubular body 4.

According to the experiment of the present inventor, the wall thickness t of the tubular body 4 is 0.05 ≦ (t / Di) ≦ 0.35 (a) based on the above-mentioned pipe inner diameter Di.
It is desirable to satisfy the relational expression. As a matter of course, assuming that the outer diameter of the tube of the tubular body 4 is Do, the wall thickness t of the tubular body 4 can be expressed as "t = (Do-Di) / 2".

The reason is that if (t / Di) <0.05, the wall thickness t of the tubular body 4 becomes smaller than the inner diameter, which makes it difficult to form the tubular body 4 and thereafter. When the tubular body 4 is incorporated into the spinneret, it is easily deformed or bent, which makes it difficult to handle, and there is a problem in terms of durability as the spinneret.

Further, when (t / Di)> 0.35, the wall thickness t of the tubular body 4 becomes large and its outer diameter Do also inevitably becomes large, so that the diameter of the merging hole 6 formed in the lower portion thereof is large. Becomes larger. Therefore, this causes the flow velocity of the sea component polymer B before and after flowing into the merging hole 6 to fluctuate greatly, and the polymer flow becomes unstable. As a result, the possibility that the core-sheath type sea-island composite flow is formed in the state where the island component polymer A is eccentric in the confluence hole 6 is increased, and the formability of a stable fiber cross section is hindered. In addition, the required opening area of the merging hole 6 per island becomes large, which is not desirable for realizing ultra-multi-islandization.

Next, the relationship between the outer diameter Do of the tubular body 4 and the pore diameter d of the polymer introduction portion of the merging hole 6 is
0.85 ≤ (d / Do) ≤ 2.0 (b)
It is desirable that the relational expression is satisfied. This is because, in the case of "(d / Do) <0.85", when the upper mouthpiece plate 1 and the middle mouthpiece plate 2 are combined, the tubular body 4 and the middle mouthpiece plate 2 provided on the upper mouthpiece plate 1 are attached. This is because the influence of the positioning accuracy with the provided introduction hole acts sensitively. Then, the probability that the core-sheath composite fiber flow is formed in the state where the island component polymer A is eccentric in the sea component polymer B increases, and the island component polymer A shifts to a position different from the initially targeted position. Since the islands are joined to each other, the island formation property in the cross section of the fiber is deteriorated. The case of (d / Do)> 2.0 is not desirable for the same reason as the case of (t / Di)> 0.35 described above.

Finally, an introduction having a funnel-like shape, in which the outer diameter Do of the tubular body group that divides the island component polymer into a plurality of polymer trickles and two or more of the core-sheath flow groups are aggregated into an integrated flow. The smallest distance Dr between the outer edge of the hole and the core-sheath composite flow group is Do ≤ Dr ≤ 5 Do (c).
Is preferable. When Do <Dr, it is not preferable that two or more core-sheath composite streams are merged because the island components of the outermost layer are brought into close contact with each other. Further, when D> 5Do, it is not desirable for the same reason as when (t / Di)> 0.35 described above.

In the present invention, a sea-island type composite fiber having an island component having a diameter of several tens to 400 nm can be produced by using the sea-island composite fiber base as described above. Further, by forming two or more tubular body groups into one composite fiber, a non-uniform pressure is applied at the polymer thinning step between the merging hole 6 and the discharge hole 7, and the island component of the sea-island type composite fiber obtained is obtained. Transforms into an ellipse. The ratio of the major axis to the minor axis of this elliptical shape is preferably 1.2 ≦ (major axis) / (minor axis) ≦ 6. It is difficult to make this value smaller than 1.2, while if it is made larger than 6, it will merge with the adjacent island components and there will be parts that cannot be weight-reduced, making it difficult to produce ultrafine fibers. .. The coefficient of variation of the ratio of the major axis to the minor axis of the ellipse is preferably 10% or more and 50% or less. It is difficult to make the coefficient of variation smaller than 10%, while if it is larger than 50%, it merges with the components of the adjacent islands, resulting in a portion that cannot be weight-reduced, making it difficult to produce ultrafine fibers.

Next, examples and comparative examples of the present invention will be described in detail, but the present invention is not limited thereto. In addition, each measurement item in an Example was measured by the following method.

(1) Island component of sea-island type composite fiber Using a long-diameter transmission electron microscope (TEM), a cross-sectional photograph of the fiber perpendicular to the fiber axis direction was taken at a magnification of 30,000 times, and the island component of the sea-island type composite fiber was taken. The circumscribing circle was calculated, and the island component major axis of the sea-island type composite fiber was calculated from the average value (n number = 100).

(2) Island component of sea-island type composite fiber Using a short-diameter transmission electron microscope (TEM), a cross-sectional photograph of the fiber perpendicular to the fiber axis direction was taken at a magnification of 30,000 times, and the island component of the sea-island type composite fiber was taken. The inscribed circle was calculated, and the island component minor axis of the sea-island type composite fiber was calculated from the average value (n number = 100).

(3) Coefficient of variation of the ratio of major axis to minor axis of island component Obtain the major axis / minor axis ratio (f) from the major axis and minor axis of each island component obtained by the methods (1) and (2) (n number). = 100), the average value (f1) and the standard deviation (σ1) were obtained, and the coefficient of variation was calculated using the following formula.
Coefficient of variation (cv%) = σ1 / f1 × 100

(4) Uniformity of Fiber Diameter of Ultrafine Fiber As the uniformity of fiber diameter in the ultrafine fiber obtained by dissolving and removing the sea component of the sea-island type composite fiber, the variation in fiber diameter (cv%) was calculated and evaluated. .. A cross-sectional photograph of the fiber was taken at a magnification of 30,000, the circumscribed circle of each single thread of the ultrafine fibers was calculated, the major axis of the circumscribed circle was obtained, and the circumscribed circle diameter data of each single thread of 100 randomly selected ultrafine fibers was used. The average fiber diameter (r2) and standard deviation (σ2) were calculated, and the coefficient of variation (cv) defined below was calculated.
Fiber diameter coefficient of variation (cv%) = σ2 / r2 × 100

[Example 1]
Polyethylene etherephthalate (manufactured by Teijin Co., Ltd.) having a melt viscosity of 100 Pa · sec for the island component, and polyethylene glycol (PEG) having a melt viscosity at 270 ° C. of 150 Pa · sec for the sea component at 270 ° C. Using polyester (modified PET1) copolymerized with 9 mol% of sodium sulfoisophthalic acid (SIP) and ethylene glycol (EG) as a dialcohol component, 720 islands 32 with a sea-island ratio of sea: island = 50:50. The core-sheath composite flow of the book was merged into one by the time of discharge, spun as a sea-island composite fiber of 1440 islands and 16 filaments, and taken up at a spinning speed of 1000 m / min to obtain an undrawn yarn.

Subsequently, the undrawn yarn was drawn using a hot roll-hot roll type drawing machine at a drawing temperature of 90 ° C. and a heat setting temperature of 180 ° C. at a draw ratio of 4 times to obtain a 28 dtex sea-island type composite multifilament. .. The sea-island composite fiber obtained had an elliptical island component, and the major axis of the island component was 250 nm. The minor axis was 200 nm.

The sea-island type composite fibers were bundled and immersed in a 4% NaOH aqueous solution at 80 ° C. for 30 minutes to obtain an ultrafine fiber bundle made of the obtained polyester. The coefficient of variation of the fiber diameter was 20%.

[Comparative Example 1]
Polyethylene etherephthalate (manufactured by Teijin Co., Ltd.) having a melt viscosity of 100 Pa · sec for the island component, and polyethylene glycol (PEG) having a melt viscosity at 270 ° C. of 150 Pa · sec for the sea component at 270 ° C. Using polyester (modified PET1) copolymerized with 9 mol% of sodium sulfoisophthalic acid (SIP) and ethylene glycol (EG) as a dialcohol component, 1440 islands 16 with a sea-island ratio of sea: island = 50:50. The core-sheath composite flow of the book was spun as a sea-island composite fiber of 1440 islands and 16 filaments without merging, and the fiber was taken up at a spinning speed of 1000 m / min to obtain an undrawn yarn.

Subsequently, the undrawn yarn was drawn using a hot roll-hot roll type drawing machine at a drawing temperature of 90 ° C. and a heat setting temperature of 180 ° C. at a draw ratio of 4 times to obtain a 28 dtex sea-island type multifilament. When the cross-sectional shape of the sea-island type composite fiber was confirmed, fusion of the island components was observed. Even if the obtained polymer was immersed in an aqueous NaOH solution at 80 ° C. for 30 minutes, fusion between the fibers occurred, and ultrafine fibers could not be obtained.

By using the sea-island type composite fiber cap of the present invention, it is possible to produce an ultrafine long fiber bundle having a finer fineness than 400 nm in diameter.

1 Upper base plate 2 Middle base plate 3 Lower base plate 4 Tubular body 5 Sea component introduction hole 6 Confluence hole 7 Discharge hole 8 Island component polymer distribution chamber 9 Sea component polymer introduction flow path 10 Sea component polymer distribution chamber

Claims (4)

A spinneret for melt-spinning a group of sea-island type composite fibers in which a large number of island-component polymers are separated from each other in one single fiber and extend independently in the sea-component polymer along the fiber axis direction. And
The spinneret is
(A) A tubular body group (4) that divides the island component polymer into a plurality of polymer trickles, respectively.
(B) A distribution chamber (10) in which the tubular body group (4) is projected inside and the sea component polymer is internally distributed so as to surround each of the tubular body groups (4).
(C) Each island component polymer is bored directly under the distribution chamber (10) in a one-to-one correspondence with each of the tubular body groups (4) and supplied from the tubular body group (4). , A confluence hole group (6) that flows down while forming a core-sheath complex flow group corresponding to the number of tubular body groups (4) by merging with the sea component polymer supplied to the distribution chamber (10).
(D) An introduction hole having a funnel shape is formed above, in which two or more core-sheath composite flow groups flowing in from each lower end of the confluence hole group (6) are aggregated to form an integrated flow. A discharge hole that is spun after guiding the integrated flow downward while gradually reducing it.
A spinneret for Kaijima-type composite fibers, which is characterized by having and. The spinneret for a sea-island type composite fiber according to claim 1, wherein the inner diameter Di of the tubular body and the wall thickness t thereof satisfy the following formula (a).
0.05 ≦ (t / Di) ≦ 0.35 (a) The spinneret for a sea-island type composite fiber according to claim 1 or 2, wherein the outer diameter Do of the tubular body and the diameter d of the introduction portion of the confluence hole satisfy the following formula (b).
0.85 ≤ (d / Do) ≤ 2.0 (b) The most distance between the outer diameter Do of the tubular body and the outer edge of the funnel-shaped introduction hole, which is a combination of two or more core-sheath composite flow groups to form an integrated flow, and the core-sheath flow group. The spinneret for a sea-island type composite fiber according to any one of claims 1 to 3, wherein a small distance is satisfied by Dr and the following formula (c).
Do ≤ Dr ≤ 5 Do (c)

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