JPH0491219A - Polyester multifilament having improved water absorption property - Google Patents

Abstract

PURPOSE:To obtain the title multifilament having specific properties, integrity between filaments reduced as much as possible and improved water absorbing properties, comprising specific thick and thin filaments having a dented part as a capillary path of open part in a cross section. CONSTITUTION:The objective multifilament comprising filament composed of polyethylene terephthalate of base polymer, having a dented part in cross section, thick parts and thin parts alternately along the longer direction, a ratio of a denier d1 of the thick parts and a denier d2 of the thin parts of >=3 and difference in shrinkage between the thick parts and the thin parts wherein value P50 at 50cm period on Uster spectrography obtained by normal test is <=0.4 the maximum value Pmax. The multifilament, for example, is obtained by drawing undrawn polyester yarn of low orientation, which is spun at a low speed and latently thick and thin, at a low draw ratio to sufficiently cause unevenness while extremely dispersing unevenness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyester multifilament with improved water absorption. More specifically, the present invention relates to a polyester multifilament with improved water absorption, which is particularly useful for cooling materials.

(Prior Art) Polyester fibers, typified by polyethylene terephthalate fibers, have excellent physical and chemical properties and are therefore widely used as materials for clothing, industrial use, and the like.

However, because this fiber has poor hydrophilic properties, its use in clothing, especially as a material for summer wear, has been limited. Of course, various methods have been proposed to impart hydrophilicity to polyester fibers. For example,
Examples include a method of copolymerizing or blending a hydrophilic compound with polyester, and a method of post-treating polyester fibers with a hydrophilic compound. And according to these chemical methods,
It is possible to impart desired hydrophilic properties to polyester fibers. However, if an attempt is made to modify the polyester to a sufficient degree to produce a material with a refreshing feel, physical properties such as oxidation stability and light fastness deteriorate, and at the same time, the inherent excellent properties of polyester are impaired.

On the other hand, as a method other than the chemical modification method mentioned above, for example, Japanese Patent Application Laid-Open No. 52-18918 discloses the so-called fiber Milr surface which improves water absorption by specifying the cross-sectional shape of fibers having open capillaries. A method of improving water absorption by modifying the shape of the material is disclosed.

Furthermore, JP-A-62-299565, JP-A-6
No. 3-50576 and Japanese Patent Application Laid-Open No. 61-83316, etc., each method involves specifying the cross section of the open capillary of the fiber, blending a hydrophilic polymer, and using a composite spinning method (by imparting hydrophilicity to the fiber itself). synergistic effect),
There are many attempts to improve water absorption. The place is
Such fibers have a drawback that their open capillary channels are easily crushed by external stress because they have long bending portions in their cross sections, resulting in a decrease in water absorption. Furthermore, when these fibers are used in knitted fabrics, etc., the fibers come into contact with each other due to the restriction within the structure, and as a result, the openings of the recesses fit into each other, blocking the open capillary passages.

This means that the water absorption performance of textiles is significantly lower than that obtained in the fiber state.

In addition, in the case of AM products, it is generally practiced to twist raw filaments for woven or knitted fabrics as a means of improving the elasticity and bulkiness of the fabrics.

However, when the raw yarn is twisted, the constituent filaments are brought together, making it easier for the filaments to fit into each other. Highly twisted fabrics with a high number of twists are widely used, especially as summer materials, for crispness and breathability. However, in such highly twisted materials, fitting between filaments inevitably and extremely occurs, so
The open capillary passages are blocked and the water absorption performance remains at a low level.In an attempt to eliminate these drawbacks, Japanese Patent Publication No. 1983-53605 discloses a specific method consisting of arms and/or slots in the cross section of the filament. It is disclosed that the presence of recesses forms capillary tubes effective for water absorption between the filaments themselves and between the filaments. According to the present invention, the openings of the recesses are set at 1/2 of the maximum diameter of the recesses so that the openings of the recesses do not fit into each other when the filaments come into contact with each other.
and whose aperture angle is 1180° or more -90
``Identified below. However, when trying to narrow the opening, the opening ends easily fuse together due to fluctuations or slight differences in the spinning conditions during the spinning process, and the opening capillary becomes occluded, resulting in a hollow state. As a result, the water-absorbing grooves are crushed, making it difficult to obtain the desired water-absorbing property, and a difference in staining occurs between the day hair #1 nts and the hollow portion, resulting in staining spots.

(Objective of the Invention) The main object of the present invention is to provide a multifilament comprising a filament having at least one concave portion in the cross section as an opening capillary path, without paying attention to the shape of the capillary path. The fitability of the is reduced as much as possible,
An object of the present invention is to provide a multifilament with improved water absorption.

Furthermore, another object of the present invention is to provide a multifilament made of filaments having at least one recess as an open capillary in its cross section, in which fitting between the filaments is difficult to occur even when the filaments are strongly twisted. The object of the present invention is to provide a multifilament that exhibits water absorbency substantially equivalent to that of raw filaments even in woven or knitted fabrics.

(Structure of the Invention) According to the research conducted by the present inventors, the fitting resistance (the extent to which fitting is unlikely to occur) between the irregularly shaped filaments is as follows: It has been found that a significant improvement is achieved when a multifilament comprising:

Thus, according to the present invention, in a multifilament consisting of filaments whose matrix polymer is mainly polyethylene terephthalate, each filament has the following properties [A] to [8] in its cross-sectional direction and longitudinal direction. On the other hand, there is provided a polyester multifilament with improved water absorption, which is characterized by having the following property [C] in its longitudinal direction.

[^] Characteristics of the filament in the cross-sectional direction: At least a portion of the cross-section must have a recess.

[B] Characteristics in the longitudinal direction of the filament: ■ It has thick parts and thin parts alternately along the longitudinal direction, and the ratio of the denier (d1) of the thickest part to the denier (d2) of the thinnest part. (d1/dz) is 3.0 or more.

■There must be a difference in shrinkage between the thick and thin parts.

[C] Longitudinal properties of multifilament The value (P5o) at a period of 50c on the Worcester spectrograph obtained in the two normal tests is 0 of the maximum value (P)
．． Must be 4 or less.

aX The present invention will be described in detail below, but before that, the background behind the adoption of the above configuration will be discussed.

The present inventors first analyzed the factors behind when the open capillary fitting between filaments occurs. As a result, we determined the following facts.

a) The morphology between the filaments is the same, and the configuration is 1 m.
In multifilaments having substantially the same physical properties in the longitudinal direction, the filaments are likely to be parallelized, and as a result, the multifilaments are easily converged and fitting between the filaments is likely to occur.

b) On the other hand, even in composite yarns made of two or more types of multifilaments with different physical properties and different yarn lengths, it is easy to separate into groups of multifilaments with the same physical properties and bundle them individually, As a result, the degree of occurrence of mating is not significantly reduced.

C) Furthermore, even if the multifilament is opened by electric opening or the like and entangled in an overfeed state, the occurrence of mating cannot be sufficiently reduced.

d) Japanese Unexamined Patent Publication No. 57-121614 discloses a cord in which constituent filaments having special U-interdisciplinary planes are uneven in thickness in the longitudinal direction. Here, it is shown that a difference in thread length is provided between adjacent filaments by so-called thick-and-thin drawing. In such simple thick-and-thin stretching, the fit between adjacent filaments can be suppressed to a fairly low level, but the degree of fit is still insufficient and the water absorption remains at a low level.

Through the above analysis, the inventors have found that the conditions under which open capillary fitting does not occur are that there is a difference in thread length at short intervals between adjacent filaments, and that there is space between the filaments. This means that it is a prerequisite that the

Next, in relation to the above-mentioned prerequisites, the necessity of the characteristics of ■^] to [C] in the present invention will be described.

Properties of IAI This, of course, presupposes the presence of open capillaries in the filament in order to obtain water absorption.

The cross section of such a filament is as shown in FIG. 1 (C is a concave portion), and more preferred examples are shown in FIGS. 2 and 3.

Characteristic [B] In order to maintain filament water absorbency, it is necessary to prevent filaments having the above-mentioned open capillaries from fitting together. For this, a sufficient thread difference (
Bulkyness) is essential, and in order to achieve this, the thick-to-thin ratio must be 3.0 or more, preferably 3.5 or more as a guideline for the shrinkage difference.

It should be noted that when the bulkiness is 35 cc/g or more, more preferably 45 cc/g or more, fitting between the filaments can be sufficiently avoided and a sufficient suction channel can be secured. In order to achieve a bulkiness of 35 CC/g or more, the ratio (d1/d2) of the denier (d1) of the thickest part to the denier (dz) of the thinnest part of the thickness unevenness must be 3.0.
Above, more preferably 3.5 or more, still more preferably 4.0 or more is required. In conventional methods, the denier ratio is at most 2.5, and such a low level does not provide sufficient bulk.

Here, the thick-to-thin ratio is the ratio between the cross-sectional area of the thick portion and the cross-sectional area of the thin portion.

[C] Requirement [8F characteristics indicate the difference in fiber length (bulkness) of the system as a whole, but only when this difference in fiber length exists at even finer intervals can the function of the open capillary be maximized. It is demonstrated.

The barameter with P 5G/-P 18x≦0.4 is,
This defines the degree of fine spacing required to ensure water absorption.

In other words, even if the above denier ratio is high, if the period of the uneven thickness is long, interlocking between fibers is unavoidable. In composite yarns such as this, bulkiness increases when the shrinkage difference and yarn foot difference are large, but the fibers fit together when the yarn foot differences are the same among filaments with similar physical properties, resulting in a decrease in water absorption. In order to provide water absorption that does not improve, high bulkiness and yarn foot difference in short cycles are required. The period can be expressed using the Worcester spectrograph developed by Zellweger in Switzerland. The Worcester spectrograph is said to be particularly useful for determining the pitch of mottles, and its details can be found in ``The theory and practice of mura''.
(Published by llfill Machine Jikai) Pages 255 to 375
It is described on the page.

In order to make the explanation more concrete, examples of spectrographs of speckled threads of the present invention are shown in FIGS. 6 and 7.

The abundance ratio of the length of the most common plaque is indicated by Plax, and the abundance ratio of the plaque length of 50 cm is indicated by P5o.

In the present invention, it is necessary that the period of the spots is sufficiently short, and when the parameter p s o /p□8 is a sufficiently small value, it is possible to suppress the long period of spots to a sufficiently small level. In order to provide a sufficiently short cycle to a level where interfilament engagement does not occur, P5
o/Plax is 0.4 or less, more preferably 0.30
It is as follows.

Next, a method for manufacturing the multifilament of the present invention will be described.

In the conventional manufacturing of thick and thin yarn by incomplete stretching, a low stretching ratio lower than the natural stretching ratio of the raw yarn is adopted, and the incompletely stretched part is not fully stretched. The result is an incompletely drawn yarn with a mixture of

However, with such speckled threads, the difference in denier and shrinkage of the threads is still small, and it is not possible to sufficiently reduce the fit between the filaments. In addition, a method of increasing the difference in denier of the filaments is adopted.

For example, when a polyester polymer is melt-spun at about 1200 m 2 /min, a fully drawn yarn with a normal elongation of about 30% is obtained at a draw ratio of about 3.0 times. In order to effectively make this into an incompletely drawn yarn, it is necessary to make the drawing ratio less than or equal to the natural draw ratio of the raw yarn (in this case, 2.5 times).

Therefore, the obtained denier ratio remains at about 2.5 times. At this time, if the stretching ratio is greatly lowered than the natural stretching ratio, the denier ratio of the mottled yarn will increase, but the mottled period will become significantly longer and the P2O'' wax will be 0.
．． The number of Im fibers exceeds 4, indicating that the Im fiber legs are aligned and interlocking occurs. Further, the degree of molecular orientation in the unstretched portion becomes extremely low, resulting in disadvantages such as a decrease in strength and difficulty in handling.

On the other hand, when the spinning speed is set low, the incomplete stretching ratio is increased, and the denier ratio is increased, the degree of molecular orientation in the unstretched portion is too low, resulting in poor handling, which is not preferable. Conventionally, various methods for producing undrawn yarn with uneven denier have been studied. For example, there are methods of drastically lowering the polymer temperature during spinning, and methods of greatly reducing the amount of cooling air.

According to the present invention, a desired multifilament can be obtained by forming a latent thick-and-thin yarn at the yarn stage before subjecting it to incomplete stretching, and applying a special uneven dispersion stretching method to the yarn.

Therefore, latent thick-and-thin yarn is used as the raw yarn (raw yarn to be drawn) shown in FIG. 1, and incomplete stretching is performed while dispersing the multifilaments.

Here, the means for dispersing the multifilament is as follows.

(+) Do not apply concentrated stress to the entire multifilament.

■ Do not heat the entire multifilament intensively.

(To) Reduce the friction between filaments.

(c)-1 Lower the amount of oil adhesion (c)-2 Spread the fibers 0 Enhance the physical properties between filaments.

To be more specific, the low-oriented polyester undrawn yarn, which is discharged through a spinneret and spun at low speed and has the potential to cause thick and thin, is processed at a low magnification sufficient to cause unevenness, and with less unevenness and dispersion than before. For example, the spinning speed is at most 2000 m.
/iin, preferably 1500 m/sin or less, and a desired thick-to-fine ratio can be obtained. Further, it is preferable to keep the amount of oil applied during spinning to 0.7% or less, and furthermore, the denier and cross-sectional shape of the filaments can be varied by using discharge holes of various shapes. In this case, it is also effective to vary the cooling air effect during spinning. It is also useful to thoroughly squeeze the yarn before drawing. The straining tension is required to be at least 0.2 g/d, but if the straining is too strong, stretching will occur in this area and the stretching will also result in spotty stretching. Moreover, at this point, spots with poor dispersibility are preliminarily formed and remain until the end, so it is important to avoid such a situation as much as possible, and only to squeeze without actually stretching. In this sense, it is best to keep the tension below 1.0 g/d. Also, during stretching, it is necessary to avoid concentrated stress and concentrated heating as much as possible, and to avoid alignment of the stretching points. In addition, it is better not to apply sudden bends, and concentrated partial heating in a narrow range is also undesirable.It is better to heat the yarn as a whole over a long range while keeping it as flat as possible. The temperature is preferably set to the glass transition temperature of the raw yarn + 55° C. or higher; if this temperature is low, the dispersion effect of dispersing the neck points over a long range during drawing will be reduced. However, even if the raw yarn is preheated in advance, the preheating temperature must not exceed this temperature too much, because the drawing points will be concentrated there. Preheating the yarn is effective in preventing stretch wrapping and improving drawability, but it is not preferable in terms of unevenness, so preheating should be done at a temperature that is not too high. It is necessary to sufficiently leave a low stretching ratio portion by stretching at a natural stretching ratio of less than or equal to . This, together with the thickness unevenness of the raw yarn, forms a thick shoulder part. If this mottling effect is not sufficient, there is no point in improving functionality by improving dispersibility.For this purpose, it is desirable to have a thick-to-fine ratio (ratio of maximum denier to minimum denier) of 3.0 times or more. A thick to thin ratio of 3.5 times or more is required.

As the yarn of the present invention, those shown in FIGS. 2 to 5, which further specify the cross section of FIG.

That is, by combining a high-speed polymer flow with a low-speed polymer flow while maintaining a sufficient flow velocity difference between the polymer flows, it is possible to pulsate the latter polymer flow and stably impart denier irregularities within and between the filaments. I discovered that. When this yarn is subjected to incomplete stretching,
It has been found that a bulkiness far exceeding that obtained by conventional methods can be obtained, there is no inter-filament between filaments, and therefore a multifilament with improved water absorption can be obtained.

FIG. 2 is a cross-sectional view of the above-mentioned preferred filament, FIG. 3 is a cross-sectional view explaining the difference between the above-mentioned filament and a normal round-section filament, and FIG. 4 is a cross-sectional view of the filament used for spinning the above-mentioned filament. FIG. 5 is a cross-sectional view showing another aspect of the spinneret.

In Fig. 2, 0 is the connecting part, h and h' are a pair of flat parts connected to the connecting part Ω, (Xl, Xso), (x2°x2°) are the connecting part Q and the flat part. [b] is the diameter of the inscribed circle of the connecting part 9, La is the flat part, and [b] is the diameter of the inscribed circle of the connecting part 9, The circumscribed circle diameters Lc and Lc' respectively indicate the maximum inscribed circle diameter of the flat portion h' divided by the boundary line.

As is clear from FIG. 2, the cross-sectional shape of such a filament consists of a pair of flat parts, and a pair of recesses (X1+X1° ) and (X 21 The filament having the above-mentioned cross-sectional shape has a higher degree of orientation in the h and h parts than the nine parts, and the zero part in the longitudinal direction of the filament has uneven thickness along the longitudinal direction. Moreover, there is a difference in shrinkage due to this thickness unevenness.

In the cross-sectional shape of the filament, as shown in FIG. It is preferable for the filament to have an asymmetric cross-sectional shape and/or to have an asymmetrical cross-sectional shape, since it is possible to increase the porosity of the filament itself and to increase the shrinkage difference in the cross-sectional direction of the filament.

As shown in FIG. 3, such a filament has a diameter of a circumscribed circle H circumscribing the cross section of the filament, which is significantly larger than the diameter of a round cross-section filament H of the same denier, indicating that the porosity is extremely large. It is preferable that the diameter of H is 1.5 times or more, particularly 2 times or more, the diameter of H.

It goes without saying that the cap shown in FIG. 4 may be modified in various ways, and an example thereof is shown in FIG. 5, which is preferably used when it is desired to impart various functions to the filament. I can do it.

As shown in Fig. 5 (a), a filament that is constructed of a filament having a shape in which a plurality of pairs of flat parts connected to a connecting part are connected in series exhibits large bulkiness and water absorption. I can do it.

In addition, especially in the case of a filament having a cross-sectional shape in which three or more (preferably 3 to 4) flat parts are arranged in an annular manner and are connected by one connecting part, as shown in Fig. 5 (C1l Ire). It can exhibit good water absorption.

A multifilament made of such filaments can suppress the interfilament to a level that is not possible with conventional techniques.

Based on this, we tried to further reduce the fit, and surprisingly, when we subjected this raw yarn to incomplete stretching, we were able to obtain bulkiness due to the unexpected difference in shrinkage. It has been found that further bulkiness can be obtained when the incomplete stretching is carried out while dispersing the multifilaments during the incomplete stretching.

The reason why such a method can provide a low level of filament-to-filament fitting that could not be obtained conventionally, as well as a high level of bulkiness that could not be obtained conventionally, will be described.

First, the characteristics of the pulsating discharge special irregular cross-section spun yarn thus obtained will be described. First, a multifilament was opened to obtain a filament, and the distribution of the single filament denier was measured. Regarding the thickness unevenness of the filament, the denier of the thickest part in the longitudinal direction (d1) and the thinnest denier (
d1) (di/d2) was in the range of 1.5 to 2.0, and the period was approximately 1.3 m to 2.3 m. In this manner, the raw yarn supplied for incomplete stretching already has physical property differences within and between filaments.

When the raw yarn obtained in this manner is placed in hot water, a considerable difference in yarn length appears even though the yarn is undrawn.

Furthermore, when incomplete stretching is performed using this raw yarn, due to the difference in physical properties of the raw yarn, there is no concentration of stress during stretching, and the yarn is easily opened by slight ironing. Since the yarn length difference is further expanded by slight heating, it is easy to keep stress concentration at a very low level, and therefore it is possible to efficiently apply incomplete stretching to each filament in a well-distributed manner. .

That is, in the present invention, the combination of pulsating discharge spinning and incomplete stretching is not limited to the mere effect of the combination, but also the shrinkage difference due to incomplete stretching synergistically with the shrinkage difference between incomplete stretching and unstretched with good dispersibility. This is intended to be an added effect.

In conventional spinning, it was common knowledge to create yarn with uniform physical properties, and attempts were made to obtain incompletely drawn yarn with dispersibility, but the results remained at a low level6.
In the present invention, the spun undrawn yarn already has a shrinkage difference and is further subjected to incomplete stretching, thereby achieving a practical high denier ratio two-dispersity (periodic ) is obtained.

A feature of the incompletely drawn yarn thus obtained is that it exhibits significantly improved bulk. That is, the bulkiness of this incompletely drawn yarn is 35CC.
/g, so fitting between filaments can be sufficiently avoided and a sufficient suction path can be secured. Prior art techniques, such as those disclosed in Japanese Patent Application Laid-open No. 1-201512, provide bulkiness when made into bulky yarn by discharging a polymer from a spinneret in a pulsating manner;
As shown in Japanese Patent No. 1-152814, when bulkiness is imparted by incomplete stretching, the value is at most 30 CC/g, and there is considerable inter-filament fitting, and water absorption is also a good value. In the present invention, in order to provide high bulkiness, a sufficiently high shrinkage difference between and within the filaments is required, and furthermore, high thickness unevenness is required within and between the filaments to provide the shrinkage difference. becomes. Bulky 35cc/g
In order to obtain the above value, the ratio (d
1/dz) at the yarn stage, preferably 3.0 or more,
More preferably 3.5 or more, still more preferably 4.
Must be 0 or more.

The polyester referred to in the present invention is a polyester whose main component is polyethylene terephthalate, which is composed of terephthalic acid or its lower alkyl derivative and ethylene glycol, or terephthalic acid or its lower alkyl derivative, ethylene glycol and at least one third component. It is.

In this case, the third component is, for example, oxalic acid.

Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid; aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, and 2゜6-naphthalene dicarboxylic acid; and polyfunctional compounds such as trimellitic acid and pyromellitic acid. lower alkyl ester or glycol ester having 2 to 10 carbon atoms.

Diethylene glycol, propylene glycol.

Examples include polyethylene glycol, butanediol, glycerin, and pentaerythritol.

If the matrix polymer itself contains a hydrophilic polymer, especially polyethylene glycol, more efficient water absorption performance can be ensured.

When the molecular weight of polyethylene glycol exceeds 6,000, there is almost no reaction with polyethylene terephthalate as a substrate polymer, and the polyethylene glycol exists in a blended state. On the other hand, those having a molecular weight of 6,000 or less may be partially copolymerized. Here, polyethylene glycol with a molecular weight of less than 1,000 is completely copolymerized, but this is not preferable because it warps and deteriorates the physical properties of the polyester.The preferred molecular weight of polyethylene glycol is 2,000 to 300.
It is 00. Whether polyethylene glycol itself is copolymerized with or blended into the matrix polymer, the end result is a multifilament with a high level of water absorption.

In this case, if polyethylene glycol is used, which has a group that does not react with the substrate polymer at one end and a group that reacts with the substrate polymer only at the other end, a block copolymer with the substrate polymer is formed. And, in filaments obtained from such copolymers,
This is preferable because polyethylene glycol separates from the substrate polymer and aggregates into amorphous parts or bleeds out on the surface. The larger the amount of polyethylene glycol added, the stronger the hydrophilicity, which is preferable, but on the other hand, the fastness deteriorates. Therefore, the preferable amount to be added is 3% to 10% by weight based on the base polymer.

(Operations and Effects of the Invention) As described above, according to the present invention, a sufficient yarn length difference (bulkness) between filaments is achieved by utilizing the shrinkage difference between the thick and thin portions of the thick and thin yarn. By realizing this and keeping the period of the thickness unevenness within a specific range, it is possible to prevent the filaments with open capillaries from interlocking, thereby maximizing the water absorption of the multifilament regardless of whether it is untwisted or twisted. can be demonstrated.

The concept of this invention was born through the following research process.

■In the case of thick and thin yarn, the difference in yarn length between filaments is generally caused by the difference in shrinkage, but this difference in shrinkage is caused by uneven thickness of the filaments, so the value of the uneven thickness and its distribution and the fit between the filaments. We analyzed the relationship between

■For filament thickness unevenness, we use the ratio (dz/dz) between the denier (d1) of the thickest part of the filament in the longitudinal direction and the denier (d2) of the thinnest part, and furthermore, for the distribution, we use the normal test. This can be shown by the shape of the Worcester spectrograph obtained in , and these were used to analyze the fit of the fibers.

■As a result, it was found that in order to obtain a sufficient water absorption effect, a large denier ratio, which cannot be achieved by conventional thick-and-thin stretching, is required. At the same time, it was also found that the more short periodic components shown on the Worcester spectrograph, the less the inter-fiber fit.

■Thus, the present invention was achieved by studying the thread difference and its periodicity, which are necessary to ensure that multifilaments with cross-sections with open capillaries do not fit into each other and provide sufficient water absorption. .

Incidentally, improving the yarn physical properties and handling properties by uniformly dispersing the unevenness of thick and thin yarn in the value of P5o/Pnax is disclosed in Japanese Patent Application Laid-open No. 152814/1983 (EPO 18736).
2).

However, there is no suggestion here of an inventive concept in which such a barameter improves the fitting resistance of filaments with each other for filaments having open capillaries.

(Measurement method adopted in the present invention) Spectrograph: refers to the Worcester spectrograph developed by Zellweger in Switzerland, and the measurement conditions are (a) normal test, (○) chart feed rate 8 m/min, (The Norichurt range is 25%.

・Bulkness: A skein of yarn (circumferential length 1.125n) was rotated 320 times, a load of 6g was hung from one end of the sample folded in half, and the sample was dry heated at 180°C for 5 minutes, and after cooling, a constant weight(
The deposition (VCl2) of 11(]) is measured under a load of 6.4 g and calculated using the following formula.

W (g) ・Water absorption: JIS L 1079-1 regarding water absorption rate
It is determined according to the 976 water absorption measurement method.

Method A (wicking method): Take 10 test cloths of approximately 20cix 20cm and insert a metal ring (diameter 15c11).
Next, using a billet that can divide water 11 into 25 ± 3 drops, drop the water droplet by drop so that the tip of the billet is at the height of ICI from the surface of the test piece.
The time (seconds) from the time a water droplet reaches the test piece until the water droplet no longer exhibits any special reflection, measured by a stopwatch.
Measure. The test was conducted 10 times and the average value is shown in seconds.

Method B (Byrezuku method): Hold up a test cloth of about 20cn x 2.5cl, take 5 pieces from each in the horizontal direction, and place each test piece at a certain height above a water tank containing distilled water at 20±2°C. Stop it with a bottle on the horizontal bar you provided. Line up the bottom ends of the test pieces and lower the horizontal rod so that the bottom ends of the test pieces are just touching the water. A metal scale is hung together with the test piece on a horizontal rod, and the height (U) of water rise due to capillary action for 10 minutes is measured.

The number of tests was 5 times, and the average value (IllM) is shown.

[Example-1] Polyethylene terephthalate (PET) having an intrinsic viscosity [η] of 0.64 was melted at 300°C and discharged at 34.0 g/min from a spinneret having 24 connected discharge holes shown in Fig. 4. Table 1 shows the dimensions of each part of the connected discharge hole used here, in terms of the amount of discharge.

Table 1 (Note) Ss = (L1 ridge 2) X Ls, S
so; ([1° ridge 2°) 2) Polymer discharge amount ratio Q s / Q 2 and discharge speed ratio V
, /V2 were set to 1.0/1.10 and 1.0/2.6, respectively. When the molten polymer flow discharged directly below the spinneret is observed with a stroboscope, the polymer flow discharged from the discharge hole (2) pulsates between the polymer flow discharged from the pair of slit-shaped discharge holes. It was observed that
Next, the polymer stream was cooled and solidified by blowing cooling air at a temperature of 20° C. and a humidity of 60% at a linear velocity of 50 cn/sec.
Apply oil to the opu in an amount of 0.4% using an oiling roller and then take it off at a take-up speed of 1300 m/min.
An undrawn multifilament of 33 de/24 fil and a denier ratio of 1.6 was obtained. Next, this undrawn yarn was put under a tension of 0.5 g/d and then passed in a zigzag manner between alumina oxide rods with a diameter of 5111 mm, and then preheated with a hot roller at 60°C, and then stretched into a flat sheet. Be careful not to slide it on a heating plate at 140°C with a straight surface without making any steep angles.
It was wound up as a 4-fil mottled thread.

The properties of this multifilament are shown in Table 2.

Using the spinneret shown in Table 2, the molten polymer was discharged at a discharge rate of 35.5 g/min in the same manner as in Example-1.

Table 3 After doubling the three yarns obtained here and giving them a twist of 200 times/m, the warp yarns were 37.2 yarns/dimension x 2. A plain woven fabric was prepared from @ yarn with a density of 64/cm, and high-pressure dyeing was performed at 130° C. for 45 minutes.

[Comparative Example-1] Using the same polymer as in Example-1, the polymer was discharged from the connecting discharge hole having 24@ of the dimensions shown in Table 3 in Fig. 4, and the Slit-shaped discharge hole m
flo) and the polymer discharge amount ratio Ql/Q2 and discharge speed ratio v, /V2 from the discharge hole (2) are respectively 1.015.
．． 1 and 1.015.4. Directly below the spinneret,
When the discharged polymer flow was observed, no pulsation was observed in the polymer flow discharged from the discharge hole (2). This is due to the large flow rate of polymer discharged from the discharge hole (2).
In addition, since the flow rate of the polymer discharged from the slit-shaped discharge holes (1) (1') is small, the polymer flow discharged from the discharge holes (2) is the same as the polymer flow discharged from the slit-shaped discharge holes (1) (flo). The pulsation disappears because it absorbs the

Next, it was cooled and solidified in the same manner as in Example 1, and then rolled up.
An undrawn multifilament of 245d13/24f was obtained (denier ratio 1.1).

Further, this undrawn yarn was drawn under the same conditions as in Example 1 except that the draw ratio was 2.4 to obtain a drawn yarn of 100 de /24 f.

Table 4 Observing the cross section of the fabric, in Example-1 no fitting was observed between the filaments, while in Comparative Example-1 about 70% of the filaments were fitted with each other.

[Example 2] A discharge amount of 28° 5 g/ was obtained from the discharge hole shown in FIG.
Example-1 except that PET was melted and discharged at a discharge amount of
Melt spinning was performed in the same manner as above to obtain an undrawn multifilament of 197 de/245 fil and a denier ratio of 1.8.

At this time, when the discharged molten polymer flow directly below the spinneret surface was observed with a stroboscope, it was observed that it was pulsating. This was stretched in the same manner as in Example-1 except that the stretching ratio was 2.0, and the result was 100 de /24 f.
A plain weave fabric was obtained in the same manner.

Table 5 Table 6 Ta.

Table 7 The spectrograph is shown in Figure 6.

[Comparative Example 2] A nozzle with a shape similar to that of Example 2, but with the same dimensions as Comparative Example 1, discharged at a discharge rate of 29.5 g/min, 204 de/245 f. An undrawn multifilament with a denier ratio of 1.1 was obtained.

At this time, when the discharged molten polymer flow directly below the spinneret was observed with a stroboscope, no pulsation was observed. Except that the stretching ratio was 2.1 times, this was stretched by the method of Example-1 and wound up to 100 de/24 fil, and a plain weave fabric was obtained in the same manner. Observation of the cross section of the fabric In Example-2, no fitting was observed between the filaments, while in Comparative Example-2, about 60% of the filaments were fitted with each other.

[Example 3] Intrinsic viscosity containing 4% polyethylene glycol (molecular weight 2500) with one end blocked with a phenoxy group [
Using polyethylene terephthalate with η] of 0.64,
A yarn with an irregular cross section of 100 d to 24 f was prepared in the same manner as in Example 2 to obtain a plain weave woven fabric.

Table 8 [Example-4] Polyethylene terephthalate (PET) having an intrinsic viscosity [η] of 0.64 was melted at 300°C to a length of 1.0 inch.

2 H-shaped connected discharge holes combining slits with a width of 0.11
The yarn was discharged from a spinneret having a diameter of 7.0 g/min at a rate of 7.0 g/min to obtain a yarn having the cross section shown in FIG. 1(b). The denier ratio of the constituent filaments was 1.5. In order to clarify the reason for such a high denier ratio, we measured the back pressure of the die at this time and found that it was extremely small, 2.0 kg/c+g2, and that the polymer discharge was in a melt fracture state. This polymer stream was cooled and solidified by blowing cooling air at a temperature of 20°C and humidity of 60% at a linear velocity of 5 C1 m/sec, and an oil agent was applied to the opu in an amount of 0.3% using an oiling roller before it was collected. Picked up at a speed of 1300m/min, 48d
A multifilament of e/24f i I was obtained.

Next, this undrawn yarn was stretched in a zigzag manner between alumina oxide rods with a diameter of 51 cm under a tension of 0.5 g/d, and then preheated with a hot roller at 60°C, and then flattened. Carefully slide the plate on a heating plate at 140°C with a flat surface at a stretching ratio of 2.0 times, without making any steep angles.
/ 24 f i l multifilament was obtained. At this time, some thread breakage was observed.

Table 9 shows the properties of the multifilament at this time.

Table 9 The three yarns obtained here were combined and twisted at a rate of 200 turns/m, and then the warp yarns were 67 yarns/size x 2. 124 to the thread
A plain woven fabric is made with a density of 11111/dimensions and heated at 130℃ x 4
High pressure staining was performed for 5 minutes.

[Comparative Example-3] In Example-4, the normal discharge amount (30 g/min),
Cooling air was blown at a linear velocity of 50 cn/sec to cool and solidify, 1.2% oil was applied to the opu using an oiling roller, and the opu was withdrawn at a take-up speed of -1300 m/min.
An undrawn yarn of /24fil was obtained.

At this time, the cross-section of the single yarn was observed, and the cross-sectional shape was almost the same, and the denier ratio of the constituent filaments was 1.01.

Next, this drawn yarn was preheated with a hot roller at 85°C, and then normal drawing was performed at a draw ratio of 2.8 times to 75°C.
A completely drawn yarn of de/24f i I was obtained.

After twisting the yarn obtained here at a rate of 200 times/m, 67 yarns/size x 2. A plain woven fabric was prepared using small yarns at a density of 124 m/dimension, and high-pressure dyeing was performed at 130° C. for 45 minutes. The results are shown in Table 10.

Table 10

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of filaments constituting the multifilament of the present invention, and FIGS. 2 and 3 are cross-sectional views of preferred filaments in the present invention. Fig. 4 is a cross-sectional view of the spinneret for producing filaments shown in Figs. 2 and 3, Fig. 5 is a cross-sectional view showing a modified example of the spinneret shown in Fig. 4, and Figs. 6 and 7 are of the Worcester spectrograph. It is a graph showing a chart. In Fig. 1, C: Open capillary in Fig. 2: g: Connecting portion, h': A pair of flat portions connected to connecting portion G. (XI, Xio), (X21X2')...
In the recesses facing each other in Figs. 6 and 7, the spots are the most a
X Existence ratio of the length that exists in large numbers P2O... Length is 50c on the spectrograph
Existence ratio of m spots Fig. 1 h Fig. 3 Fig. 2 L (a) Fig. 4 Fig. 5

Claims (1)

[Scope of Claims] (1) In a multifilament consisting of filaments whose substrate polymer is mainly polyethylene terephthalate, each filament has the following properties [A] to [B] in its cross-sectional direction and longitudinal direction. have,
On the other hand, the multifilament is a polyester multifilament with improved water absorption, characterized by having the following property [C] in its longitudinal direction. [A] Characteristics of the filament in the cross-sectional direction: At least a part of the cross-section has a recess. [B] Characteristics in the longitudinal direction of the filament: (1) Thick parts and thin parts alternate along the longitudinal direction, and in this case, the denier of the thickest part (d_1) and the denier of the thinnest part (d_2) The ratio (d_1/d_2) is 3.0 or more. (2) There is a difference in shrinkage between the thick part and the thin part. [C] Longitudinal properties of multifilament: The value (P_5_0) at a period of 50 cm on the Worcester spectrograph obtained in the normal test is the maximum value (Pmax)
Must be 0.4 or less. (2) The polyester multifilament with improved water absorption according to claim 1, wherein each filament has the following properties [A] to [B] in its cross-sectional direction and longitudinal direction. [A] Characteristics of the filament in the cross-sectional direction: (1) A connecting part that connects at least one pair of flat parts arranged at intervals has an end joined to a side surface in the longitudinal direction of each flat part. and (2) the maximum inscribed portion of each of the flat portions divided by a straight line that is on the shortest distance between the pair of recesses, and (2) the inscribed circle diameter (LB) of the connecting portion is on the shortest distance between the pair of recesses. It should be larger than the circular diameter (LC), (LC'). [B] Longitudinal direction of filament: (1) The degree of orientation of the connecting portion is lower than that of the flat portion. (2) It has thick parts and thin parts alternately along the longitudinal direction, and the ratio of the denier (d_1) of the thickest part to the denier (d_2) of the thinnest part (d_1/d_2)
) is 3.0 or higher. (2) There is a difference in shrinkage between the thick part and the thin part. (3) The polyester multifilament with improved water absorption according to claim 2, which has a denier ratio (d_1/d_2) of 3.5 or more. (4) The polyester filament with improved water absorption according to claim 1, 2 or 3, wherein P_5_0/Pmax is 0.3 or less. (5) Claim 1, wherein the substrate polymer contains a hydrophilic component.
Or the polyester multifilament with improved water absorption according to 2. (6) The polyester multifilament with improved water absorption according to claim (4), wherein the hydrophilic component is a polyethylene glycol compound.