JPH02160917A - Polyester fiber for dustless clothes and woven fabric thereof - Google Patents

Abstract

PURPOSE:To obtain the subject fiber, consisting of polyethylene terephthalate, having a low birefringence ratio and specific small-angle X-ray equatorial scattering intensity, hardly fibrillating due to excellent abrasion resistance and capable of providing fabrics suitable as dustless clothes. CONSTITUTION:The objective fiber which is fiber consisting essentially of polyethylene terephthalate, having >=0.12 birefringence ratio and the maximum of a small-angle X-ray equatorial scattering intensity curve present at 0.02-0.04rad diffraction angle. The above-mentioned fiber is obtained by carrying out spinning in one high-speed spinning step at >=4500m/min and reducing the distance between a spinning machine and winder to decrease action of air drag. Furthermore, means for setting the molecular weight of the polyester at a rather high value, narrowing the molecular weight distribution, setting the melt spinning temperature at a rather low value, etc., are preferably combined.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to polyester fibers, and more particularly to polyester fibers for dust-free clothing having extremely excellent abrasion resistance.

<Prior art> In recent years, problems caused by dust have become a problem in the electronic equipment, precision equipment, and film manufacturing industries, and these industries are using dust-free clothing with antistatic properties in clean rooms. Work is done while wearing it. As fabrics for dust-free clothing, fabrics made of polyester multifilament having no fiber ends and having high strength are often used in order to prevent dust from being generated from the clothes (material dust).

However, in these uses, although material dust generation is relatively suppressed in the early stages when the number of times the clothes are washed (number of times worn) is small, the dust generation increases as the number of times the clothes are worn increases, making it difficult to use as dust-free clothing. The disadvantage is that it loses functionality.

The cause of this performance decline is fibrillation of the polyester filament. In other words, in conventional polyester fibers, fibrils parallel to the fiber axis are generated due to repeated friction during washing or work, and the abrasion particles are scattered and become a source of dust.

Furthermore, even in the field of these dust-free garments, organic or inorganic modifiers having the same function as antistatic agents are often added and kneaded into positive esters. In these modified polyester fibers, the fibrillation is further promoted.
The effect of suppressing dust generation is further reduced.

Furthermore, if the cross section of the filament 1 constituting the dust-free garment is not perfectly round, such as in a square shape, fibrillation is further promoted, which is a major drawback as a dust-free garment.

As described above, fibrillation of fibers is an undesirable cause of dust-emitting properties of dust-free clothing, but there are currently no sufficient means to solve this problem.

For example, polymer modification of the polyester itself, such as increasing the molecular weight of the polyester or introducing flexible polymer segments in the form of copolymerization, and changes in the spinning method to increase the elongation of the fiber by decreasing the drawing ratio. etc. have been proposed, but the above problems have not yet been solved.

<Object of the Invention> The present invention was made against this background, and an object of the present invention is to provide a polyester fiber that has extremely excellent abrasion resistance, is difficult to fibrillate, and can yield a fabric suitable for dust-free clothing. shall be.

<Structure of the Invention> In order to solve the above-mentioned problems, the present inventors conducted a detailed study on the higher-order structure of polyester fibers and found that there is a strong correlation between small-angle X-ray equatorial scattering intensity and fibril resistance. However, the present invention was achieved.

That is, the present invention provides a polyester fiber mainly composed of polyethylene terephthalate, which has a birefringence of 0.
．． 12 or less, the small angle X-ray equatorial scattering intensity curve has a maximum of 0.0
A polyester fiber for dust-free clothing and a fabric thereof, characterized by a diffraction angle of 2 to 0.04 radian.

In the present invention, the polyester mainly composed of polyethylene terephthalate refers to a polyester in which 90% by weight or more of the total amount is polyethylene terephthalate. However, 10% by weight of unvortexed matting, improved dyeability, anti-static,
There is no problem even if inorganic/organic compounds for improving hand feel or other purposes are added and mixed and/or copolymerized.

In the polyester IIi material of the present invention, it is necessary that the equatorial scattering peak of small-angle X-rays exists at a diffraction angle of 0.02 radian to 0.04 radian. This certification is performed as follows.

The small-angle X-ray scattering intensity was measured using an X-ray generator (Ru
-300), and CuKα rays (1,5418 people) monochromated using an NI filter are used as a radiation source, and a goniometer (ON 22035F> manufactured by Rigaku Denki Co., Ltd.) is used for measurement.The scattering intensity in the equator direction is 1st pinhole 0.2 Oboro φ, 2nd pinhole 0.15 #φ.

The sample is measured by collimation consisting of PSPC. The front surface of the PSPC probe (effective length 5 ctg) has a height of 1 to cut off scattering from directions other than the equatorial direction.
Insert horizontal slit H. Here, from the sample P
The distance to the SPC is 250 meters.

The scattering intensity curve thus measured is shown in FIG.

The fiber of the present invention has a peak or shoulder in this curve.

Next, it is necessary for the polyester fiber of the present invention that the average birefringence of the entire fiber is 0.12 or less.

For this measurement, C:, arl Z eiss J e
Birefringence (Δ71=TL//-nl) was determined by measuring the refractive index in the direction parallel to (nl) and perpendicular to the fiber axis (nl) using Interfaco, an interference microscope manufactured by NA.

A mixture of α-bromnaphthalene and olive oil was used as the immersion liquid. The refractive index distribution is 1 (Jhnle et al.'s method [Mak
romol, Chem, 178.2725 (197
7)], the measurement was carried out from the outermost layer of the fiber.

As described above, the polyester fiber of the present invention is characterized in that its birefringence is lower than that of ordinary polyester fiber.

The polyester fibers of the present invention are produced by highly oriented spinning, especially at high speed spinning at a yield of 4500 m/min, rather than by the usual two-step method of spinning and drawing, or by the direct drawing method in which spinning and drawing are continuous. is preferred. When a stretching process is involved, the maximum on the small-angle X-ray equatorial scattering curve described in the present invention can hardly be recognized.

Furthermore, even in high-speed spinning as described above, measures such as setting the molecular weight of the polyester to a high value, making the molecular weight distribution as sharp as possible, increasing the pore area of the spinneret, and setting the melt spinning temperature to a low value are taken. It is more preferable to combine them appropriately. On the other hand, a method in which a heating cylinder is provided during spinning to heat the running yarn is not preferred because the maximum small-angle X-ray equatorial scattering often disappears.

In any case, there is no need to particularly limit the spinning method; it is important that the polyester fiber has the above-mentioned fine structure, and at this time the abrasion resistance (fibril resistance) is dramatically improved.

However, since the above-mentioned spinning method generally deteriorates the spinning condition, it is necessary to focus the spun multifilaments using an air nozzle or the like, or shorten the distance between the spinning machine and the winding machine to reduce air drag. It is preferable to add measures such as reducing the effect of

Conventionally known methods can be used to weave a dust-free garment fabric using the polyester fibers of the present invention as described above. However, it is necessary that the fibers have no fiber ends, that is, long fibers, and that at least 50% or more of the polyester fiber of the present invention is used.

<Operations and Effects of the Invention> For comparison, the polyester thread ω of the present invention and a polyester thread <b> spun by two steps of ordinary spinning and drawing were prepared.
An abrasion test was conducted on the yarn, and a photograph of the single yarn cut is shown in Figure 2. In <b+, the diameter is thick and the fibrils are divided into long fibrils, whereas in the case of In the abrasion test, the number of fluffs generated was extremely small compared to the number of fluffs generated in the mountains.

As described above, the polyester fiber of the present invention has unprecedented fibril resistance. The first reason for this is presumed to be that the fibers of the present invention are composed of microfibrils of uniform thickness. Conventional polyester fibers are also considered to be aggregates of microfibrils, but many of these microfibrils are generally non-uniform, with some thick fibrils and some thin fibrils mixed together. In this way, when the diameters of the fibrils are uneven (more precisely, when the distances between the fibrils are uneven), no peak is observed on the equatorial scattering curve of small-angle X-rays.

When an external force such as a shearing force acts on a polyester fiber composed of non-uniform microfibrils, the stress concentrates on particularly weak fibril interfaces, probably on the interfaces of fibrils with small diameters. When the cohesive force at the fibril interface can no longer withstand stress, structural changes occur in the fibril arrangement, leading to macroscopic fibrillation.

On the other hand, the polyester II of the present invention is considered to be an aggregate of uniform microfibrils, as suggested by the presence of a small-angle X-ray equatorial scattering intensity peak. Therefore, the shearing force is evenly distributed to each fibril, and stress concentration is reduced. As a result, it is thought that the polyester fiber of the present invention exhibits less fluffing (single filament breakage) in an abrasion test, and even if breakage occurs, the fractured surface becomes a thin and short fibril.

Another reason for the improved fibril resistance is that the birefringence of the fibers is low, that is, the molecular orientation is lower than that of ordinary polyester fibers. The shearing force that acts on the uneven surface area also propagates to the internal molecular chains, but if these molecular chains are poorly oriented, this external force is absorbed as deformation of the molecular chains inside the fiber. Conceivable.

For the above reasons, the polyester fiber of the present invention has unprecedented fibril resistance,
When made into a dust-free fabric, the amount of material dust generated can be extremely reduced. In particular, when the fiber cross section is not circular, for example, a triangular cross section yarn, fibrillation and accompanying material dust generation significantly increases in conventional fibers, but in the case of the present invention, there are fewer single yarn breakages in the abrasion test, and Since the cut portions are not significantly fibrillated, significant improvements in the textile field can be achieved. Furthermore, in the case of dust-free garment fabrics, modifiers are added for various purposes such as improving hand feel, dyeability, and imparting water absorption, and often alkali treatment is also performed. In such cases, fibrillation of the fibers often becomes extremely noticeable, but in the case of the present invention, such fibrillation can also be reduced.

The polyester fiber invented by Ikemizu can be used in fabrics such as linings and interlinings, thin work clothes, wiping cloths, sports clothing, etc.
Improvements can also be expected in the field of anti-building material (non-fibrillary anti-building material).

<Examples> Example 1 Polyethylene terephthalate (PET) with an intrinsic viscosity of 0.64 and containing 0.3% by weight of titanium oxide as a matting agent.
) The chips were dried at 160°C for 4 hours and then discharged from a spinneret with 24 circular holes of 0.4# diameter at a spinning temperature of 285°C. Discharge filament is 10 to 90 below the cap.
The fibers were cooled by cross-blown cooling air at a wind speed of 30 ctn/sec, and wound into a winder located 3 m below the spinneret at various speeds of 4,000 to 6,500 m/min. The filament obtained was 75 de/24 fi l.

Also, for comparison, 1500m/min, 3000m/min, 4
500m.

After winding at 5000m, preheating is 80℃ and slit heater temperature is 180℃, 3.2 times, 1.7 times, 1, respectively.
．． Stretched 33 times, 1.2 times 75 de/24 f i
1 of multifilaments were obtained.

120 filaments obtained as above/
It was woven into a plain weave fabric with a weft of 106 strands/inch, subjected to the usual relaxing scouring and heat setting (180°C x 1 minute), and then tested using a friction tester type ■ based on J I 5-1-0823-1971. A test was conducted under the conditions of a load of 200j7° and 5,000 reciprocations.

Table 1 shows the number of fluffs (single filament breakage) generated and the observation results of the fractured surface using a scanning electron microscope, along with the shape of the equatorial scattering intensity curve of small-angle X-rays and the birefringence of the fiber.

fruit! In N05 and 6, the occurrence of fuzz is extremely high.

Moreover, the fracture surface splits into thick and long fibrils,
It is not suitable as a cumulative measure of fibril resistance. Next implementation N
Although the occurrence of fuzz was considerably reduced in samples o, 7 and 8, it was still not at a satisfactory level. These fractured surfaces are still fibrillated, but the length is slightly shorter.

Next, in Example No. 1, a lot of fuzz was generated, and the fractured surface took a fused shape. This is due to the fact that no crystallization occurs in 1liH. For the same reason, No. 1 also has high shrinkage in boiling water and is thermally unstable, so it cannot be put to practical use.

In contrast to the above, in the case of implementation Nos. 2 to 4 of the present invention, not only little fuzz is generated, but also the fractured surface has a thin and short fibril shape, so it is preferable as a fibril-resistant material.

These reasons are due to the existence of a unique maximum in small-angle X-ray equatorial scattering and the small birefringence of the fibers, as described above.

[Brief explanation of the drawing]

Figure 1 shows the scattering intensity curve of small-angle X-rays in the equator direction.
. In the figure, (a) is a fiber corresponding to the present invention, and +b+ is a polyester fiber obtained by two conventional spinning and drawing steps. FIG. 2 is a scanning electron micrograph showing the tip of a cut filament from an abrasion test. In the figure (the vessel corresponds to the present invention, (b) is a polyester fiber obtained by two steps of normal spinning and drawing, and (C) is a reduced view of (b). Patent applicant: Teijin Ltd. etiquette
Patent Attorney Former 1) Jun Hiroshi/Ku N. Tsuka Procedural Amendment (Method) % Formula % 1. Indication of the case Japanese Patent Application No. 31294.8 2. Name of the invention Polyester fiber for dust-free clothing and fabric thereof Osaka, Osaka Prefecture 1-6-7 Minamihonmachi, Chuo-ku, Tokyo (300) Teijin Limited Agent 2-1-1 Uchisaiwai-cho, Chiyoda-ku, Tokyo (Iino Building) 5. Date of amendment order: March 28, 1999 Subject of amendment Contents of drawing correction Figure 1 of the drawing will be corrected as shown in the attached sheet.

Claims (2)

[Claims] (1) A polyester fiber mainly composed of polyethylene terephthalate, the birefringence of which is 0.12 or less,
The small-angle X-ray equatorial scattering intensity curve has a maximum of 0.02 to 0.04.
A polyester fiber for dust-free clothing that has a diffraction angle of radians. (2) A dust-free clothing fabric woven from the polyester fiber according to claim (1), which is a long fiber.