JPS5936008B2 - Special multi-filament yarn - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to highly variable and uneven yarns made of synthetic fibers.

More specifically, the present invention relates to a multifilament yarn in which thick portions, thin portions, and intermediate thickness portions are arranged irregularly in the fiber axis direction and between the fibers.

[Prior art and its problems]

Natural fibers have uneven thickness, but generally the fiber cross-sectional area changes monotonically in the fiber axis direction.

Man-made fibers are generally made by spinning and drawing, and usually produce fibers with virtually no unevenness in thickness. It is well known that variations in the stretching ratio, stretching length, stretching atmosphere, etc. cause thickness unevenness in fibers.

The thickness irregularities of the fibers formed as described above are formed regularly in the fiber axis direction.

In principle, it is possible to irregularly form thickness irregularities by irregularly performing the above fluctuations, but it is expected to be extremely difficult to implement industrially, and there is no example of this being practiced.

Furthermore, it is more difficult to form different thickness uneven phases on each side of the fibers, and all the fibers tend to have the same thickness uneven phase.

When an undrawn fiber with a constant stress elongation region is drawn to a value lower than the natural draw ratio of the fiber, undrawn portions remain at irregular positions in the fiber axis direction of the drawn fiber, resulting in uneven thickness. It is also well known that certain fibers are formed.

However, if the film is simply stretched below the natural stretching ratio, thin portions with a predetermined thickness and thick portions with a predetermined thickness will be formed alternately.

Furthermore, in the multifilament yarn obtained by the above method, all the fibers tend to have the same thickness and uneven phase.

As a known example similar to the present invention, there is a technique in which the fiber cross section is deformed by pressing a filament yarn with a pair or more of hard rollers (Hibun "Sho 47-47542 Publication").
.

However, such techniques only result in deformation of the fiber cross section;
It has the disadvantage that it is not possible to control thick details.

Another known example is the technique disclosed in Japanese Unexamined Patent Publication No. 49-54626.

This technique is a method of unevenly drawing a low-oriented undrawn yarn at a high temperature.

However, the yarn with thick and fine fibers obtained by this method is
The period of the thick portion is long, and the problem is that it lacks fine changeability and is rather similar to drawn yarn.

As a further prior art, there is a method disclosed in Japanese Patent Application No. 50-68921 (Japanese Unexamined Patent Publication No. 51-147616).

In this method, undrawn yarn or highly oriented undrawn yarn is unevenly stretched at a low temperature below (glass transition point + 40 degrees Celsius) (approximately 110 degrees Celsius or below). It became an and-thin yarn, which again had the drawback of poor micro-variability.

[Object of the present invention]

The present invention improves the above-mentioned problems of the prior art and provides a yarn with further excellent fine changeability.

In other words, the fibers have thickness irregularities, and the thick portions, thin portions, and intermediate thickness portions are arranged irregularly in the fiber axis direction, and the phase of the thickness irregularities among the fibers is irregular. A multifilament yarn is provided.

[Configuration of the present invention]

The present invention was obtained as a result of intensive research to achieve the above object, and has the following configuration.

"A multi-filament yarn composed of synthetic fibers in which thick portions, thin portions, and intermediate thickness portions are arranged irregularly in the fiber axis direction. The distribution is such that the median value of the cross-sectional area of all the fibers is smaller than the average value of the cross-sectional area of all the fibers appearing at all the cutting locations of the multifilament yarn, and the fluctuation rate of the fiber cross-sectional area is If it has a value between 7% and 30% and is divided into a width of half the standard deviation from the average value to the thicker side, the probability that it will be distributed in one division area will be adjacent to the narrower side of the division area. The probability of distribution in the split area is three times or less, and the standard side i of the average fiber cross-sectional area of the multifilament yarn cross section ((standard deviation button of the fiber cross section divided by (fourth of the number of fibers making up the average multifilament yarn cross section) (1st power or less).

” The present invention will be explained in more detail.

The multifilament yarn of the present invention is composed of fibers F in which thick portions, thin portions, and intermediate thickness portions are arranged irregularly in the fiber axis direction, as shown in Fig. 1, and the fiber cross-sectional area is Regarding the distribution state of , the following four conditions are satisfied.

Figure 2 shows that the number of fibers constituting the multifilament yarn cross section at m locations equally spaced or randomly selected on the multifilament yarn Y is n(1), respectively.
n(2), n(3), -”...n (m-1)
, n(i).

Table 1 shows the cross section of the i-th multifilament yarn.

(i) The cross-sectional area of the fiber is S(i,1),,S(i,2
).

S(i, 3), -, S(i, n(i)-1)
.

S(i, n(i)), and the circular average fiber cross-sectional area of the multifilament yarn cross section is 5(i).

First matter: The fiber cross-sectional area is distributed biased towards the narrower side.

That is, when the total number of fibers constituting the multifilament yarn cross section in Table 1 above is N, it is expressed as follows.

When the total number N of fibers appearing at all the cutting locations determined by this equation (2) is arranged in order from the larger or smaller cross-sectional area of the fibers, the one located in the center is taken as the median value.

However, if N is an even number, it is the average value of the N/2th fiber cross-sectional area from the largest and smallest of the N fiber cross-sections, and if N is an odd number, it is the average value of the N/2 fiber cross-sectional area from the largest and smallest of N fiber cross-sections. The fiber cross-sectional area is (N+1)/2nd from the larger or smaller one.

Next, the "average value" in the present invention refers to the average value of the fiber cross-sectional areas of the total number N of fibers described above.

That is, if this average value is S, It is indicated by.

Also, since equation (1) is calculated, equation (3) is calculated from equation (1).
') to obtain the following equation (3).

The multifilament yarn of the present invention has a relationship between the median value and the average value obtained as described above.
・・・・・・・・・・・・・・・・・・・・・(4) must be satisfied.

This means that many thin parts and few thick parts coexist.Conversely, when a few thin parts and many thick parts coexist, the effect of mixing is small, and the thick parts The characteristics of the parts become subjective, which is not desirable.

Second matter: The fluctuation rate of the fiber cross-sectional area is between 7% and 30%.

That is, when the standard deviation is ■, the fluctuation rate V/S is o, o 7<V/S<0.30...
・・・・・・・・・・・・・・・(6).

When the variation rate V, /S is 7% or less, the effect of fiber thickness unevenness is small, and when it is 30% or more, the thick part does not blend into the whole.

A more preferable variation rate V/S range is between 10% and 20%.

Third point: Figure 3 shows the distribution of N fiber cross-sectional areas, and shows the frequency distribution divided into classes with a width of 1/2 of the standard deviation ■, with the mean value S as the boundary. , the frequencies of distribution in the thicker class from the average value S are N(1) and N, respectively.
(2) , N(3), ......, N(A-
1).

N-(1) indicates a state in which the frequency of distribution in the (l+1)th and higher classes is zero.

In the frequency distribution shown in Figure 3, N (i + 1)/N(iK3 (i = 1.2
．． 3.・・・・・・、l)・・・・・・・・・・・・・・・
(It is power.

This indicates that a portion of intermediate thickness exists.

More preferably, N (i + j )/N(i)(3(
i = 1.2, 3. ......, l) (j = 1
．． 2, 3.・・・・・・・・・7)・・・・・・・・・・・・
...(8).

If there is no intermediate-thickness portion, and thick portions and thin portions coexist, the thick portions will exhibit a foreign body effect, which is undesirable.

Fourth matter: Let the standard deviation W of the average fiber cross-sectional area within the multi-filament yarn cross section be the average number of fibers constituting the cross-section of the multi-filament yarn n = N7m... ...
・・・・・・・・・・・・・・・・・・・・・・・・0
0), the following formula % formula %) is satisfied.

To simplify the problem, consider the multifilament yarn as a multifilament yarn.

In other words, n = n (i) (i = 1.2.3-
, m ) =−(a).

The variation rate W/S of the average fiber cross-sectional area within the cross-section of the multifilament yarn is the fourth
As shown in the figure, in the case of multifilament yarn in which each fiber has completely the same thickness unevenness phase, W/S = V/S ・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・(b)
In the case of a multi-filament yarn in which the thickness unevenness phase of each fiber is completely irregular as shown in FIG.

The actual fluctuation rate W/S is between the equations (b) and (C), and is expressed as the degree of irregularity K of the uneven phase of the thickness of each fiber constituting the actual multifilament yarn. In this case, the multi-filament yarn of the present invention has K>0.5.
・・・・・・・・・・・・・・・・・・・・・・・・
...(e).

The 0υ equation can be derived from equations (d) and (e). That is, the following expansion can be made from equations (d) and (e).

log (v7vv), > lOg (rl'/4
)V/W＞n1/4 ,', V/(n巳/4〉W ・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・(11) In order to check whether the multi-filament yarn adopts the structure of the present invention, a large number (m is 30 or more, preferably is 50 or more), a large number (N is 500 or more, preferably 1000 or more)
It is necessary to investigate the fiber cross section of the above).

The longer the distance between the cross-sectional positions of the multifilament yarns, the better; it may be several centimeters or more, and one meter is sufficient.

The number of fibers constituting the multi-filament yarn cross section (i) may be the actual measured number of fiber cross-sectional areas in the multi-filament yarn cross section.

The fiber cross-sectional areas S(i,k) and S(j,
It does not need to be the same fiber as k).

[Effects of the present invention]

As described above, the multi-filament yarn of the present invention is composed of fibers in which thick portions, thin portions and intermediate thickness portions are arranged irregularly in the fiber axis direction, and with regard to the distribution state of the fiber cross-sectional area, (
By satisfying equations 4), 6), force equation, and α0 equation, thick portions, thin portions, and intermediate thickness portions of the fibers are appropriately mixed and dispersed, resulting in excellent fine changeability.

Furthermore, it exhibits the following various excellent effects.

First, there is an excellent denier mix effect.

Ordinary denier mixed multifilament yarn is a bundle of filament fibers of different thicknesses, and has the defect of insufficient mixing in the cross-sectional direction of the bundle, but the structure of the multifilament yarn of the present invention For filament fiber bundles that adopt , it is best to mix the denier in the east direction.

In addition, a normal blended yarn of different fineness is a mixture of stable fibers of different thicknesses, but the spinning characteristics due to the difference in fineness, especially the behavior of the fibers when drafted, are different and various undesirable phenomena occur.

The spun yarn having the structure of the multifilament yarn of the present invention can be obtained without causing the above-mentioned undesirable phenomena.

Second, when fiber thickness unevenness has a difference in strength and elongation, in tow spinning, if the tow adopts the structure of the multifilament yarn of the present invention, the thickness can be extremely uniform in an extremely simple process. It is possible to obtain a stable fiber bundle with excellent fiber end dispersion.

In addition, in fluffing multifilament yarn, if the multifilament yarn adopts the structure of the multifilament yarn of the present invention, it can be carried out in an extremely simple process, and the number of fluffs can be reduced to a part of the fiber with an intermediate thickness, that is, an intermediate strength. It is easy to control because there are parts.

In addition, even when fibers have various physical property differences such as dyeing differences, heat shrinkage differences, melting point differences, etc. due to uneven thickness of the fibers, the multi-filament yarn of the present invention can be made by mixing fibers having the physical property differences or A more preferable mixing and dispersing effect can be obtained than by blending.

Next, an example of obtaining a multifilament yarn of the present invention will be described.

In the Examples, "natural drawing ratio" refers to the drawing ratio at the end point of the flow region shown in the load-elongation curve of the highly oriented undrawn yarn.

This concept is, for example, the same as that described in "Polyester Fiber" by Ludewig (co-translated by Itaru Nakamura and Masaru Yokouchi, published by Corona Publishing, March 15, 1962), pp. 129-131.

Example 1 Melt-spinning polyethylene telescrate to 2500
A multifilament yarn of 300 denier and 48 filaments was obtained.

The yarn was stretched at 150 m/mtn in a drawing zone of 60 cIrL.
While drawing at a drawing speed of 83% and a drawing ratio (drawing ratio/natural drawing ratio) of 83%, a curvature radius of 3rrL, a length of 30crrL and a temperature of 130°C was brought into contact with the center of a hot plate of 15CrrL. The structure of the multifilament yarn of the present invention was satisfied.

The fibers in the thick part have better dyeability than the fibers in the thin part.

They had differences such as high heat shrinkage and high elongation.

Even when the stretched multifilament yarn was subjected to a normal temporary twisting process, the structure of the multifilament yarn of the present invention was satisfied.

When it was carried out at a tentative twist number of 2400 T/m and a tentative twist temperature of 220° C., the fibers in the thicker portions had better dyeability than the fibers in the thinner portions.

When it was carried out at a tentative twist number of 1700 T/m and a tentative twisting temperature of 230° C., the fibers in the thicker portions were extremely brittle compared to the fibers in the thinner portions, and when the fluid entanglement treatment was performed after the tentative twisting, a large number of fluffs were generated.

When it was carried out at a tentative twist number of 1900 T/m and a tentative twist temperature of 240° C., the fibers in the thicker portions were fused.

In the above, the normal spinning speed is 1000 m/mi.
The radius of curvature of the hot plate during stretching was 20
mm, the heating plate temperature was 100° C., the stretching ratio was 100%, etc., the structure of the multifilament yarn of the present invention was not satisfied.

Furthermore, in order to confirm the effects of the present invention, the following experiment was conducted.

Three types of filaments made of polyethylene telescrate shown below were prepared and processed under the drawing and heating conditions shown in Table 1.

282d-48fil Natural stretching ratio 1.88 (spinning speed 2500 m/9) 195d-48fil Natural stretching ratio 1.30 (spinning speed 3800 V min) 450 d-48fil Natural stretching ratio 3.00 (
The results obtained are shown in Table 2.

In addition, in Table 2, there are 60 measured cutting points for the yarn (
Total fiber N=2880).

*1: One using a heating pin (others used a heating plate). Also, the thread obtained from the above experiment was heated at 220°C and the number of twists was 1700.
False twisting was performed at T/M and 2400 T/M (the stretching ratio during false twisting was set to be the stretching ratio during false twisting x the stretching ratio in the above experiment - the natural stretching ratio).

The experimental results are shown in Table 2 (the experimental forms above are indicated with a dash).

(V/S X 100%) individual item evaluations are in accordance with Table 1.

All other evaluation items are marked ○. It was found that the evaluation was significantly improved by false twisting.

Although the scope and principle for obtaining the multi-filament yarn of the present invention are not clear in the above, if the fibers without even crystallization before drawing are drawn at high temperature (above the crystallization initiation temperature), flow drawing occurs, and the drawing ratio Even if it is less than 100%, it can be stretched uniformly.

Even when the contact resistance with the hot plate is large and the stretching tension increases as the temperature of the fiber increases, the fiber can be stretched uniformly.

If the fiber before stretching is crystallized, for example, 1000
In the case of fibers spun at m/min and heat treated at 140°C, even if drawn at high temperatures, almost no portions of intermediate thickness will be formed, similar to when non-heat treated fibers are drawn at low temperatures. First, the structure of the multifilament yarn of the present invention is not satisfied.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing fibers with uneven thickness. FIG. 2 is a schematic diagram showing a multifilament yarn, and shows the number of fibers constituting the multifilament yarn cross section at each multifilament yarn cross section position. FIG. 3 is a frequency distribution graph showing the cross-sectional area distribution state of the fibers constituting the multifilament yarn. FIG. 4 shows a state in which the thickness unevenness phase of the fibers constituting the multifilament yarn is completely irregular. FIG. 5 shows a state in which the thickness unevenness phase of the fibers constituting the multifilament yarn is completely irregular. 1 to 5 are schematic diagrams schematically shown to explain the structure of the multifilament yarn of the present invention.

Claims (1)

[Claims] 1 A multi-filament yarn composed of synthetic fibers in which thick portions, thin portions, and intermediate thickness portions are arranged irregularly in the fiber axis direction, and all cut points of the multi-filament yarn are The distribution is such that the median value of the cross-sectional area of all the exposed fibers is smaller than the average value of the cross-sectional area of all the fibers appearing at all the cut points of the multifilament yarn, and the cross-sectional area of the fibers is Volatility rate is 7% to 30
%, and 2 standard deviations from the mean value on the bold side.
When divided into 1/1 width, the probability of being distributed in one divided area is less than three times the probability of being distributed in the divided area adjacent to the narrow side of the divided area, and the circular average fiber cross-sectional area of the multifilament yarn cross section is A special multi-filament yarn characterized in that the standard deviation of the fiber cross-sectional area divided by (the average number of fibers constituting the cross-section of the multi-filament yarn to the quarter power) or less.