JPH02160918A - Polyester fiber for dustless clothes excellent in abrasion resistance and woven fabric thereof - Google Patents

Abstract

PURPOSE:To obtain the subject fiber which is fiber, consisting essentially of polyethylene terephthalate, produced by high-speed spinning without drawing and having specific physical properties, 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 obtained by winding at >=6500m/min speed without drawing and having <=0.09 birefringence ratio in the central part and the maxi mum of a small-angle X-ray diffraction equatorial scattering curve present at <=0.02rad diffraction angle. Furthermore, the above-mentioned fiber is prefer ably obtained by combining 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., simultaneously reducing the distance between the spinning machine and a winder to decrease action of air drag.

Description

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

<Prior art> In recent years, problems caused by dust have become a problem in industrial fields such as electronic equipment, precision equipment, and film manufacturing. Work is done while wearing clothes. As the fabric for this dust-free clothing, in order to prevent dust from being generated from the clothing (material dust), a fabric that does not have fiber ends and uses strong polyester multifilament is often used.

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 dust-free clothing, organic or inorganic modifiers having antistatic agents and other functions are often added and kneaded into polyester. In these modified polyester fibers, the front 2 fibrillation is further promoted, so
The effect of suppressing dust generation is further reduced.

Furthermore, if the cross section of the filaments constituting the dust-free garment is not perfectly circular, 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 can be applied without being substantially stretched.
A polyester fiber mainly composed of polyethylene terephthalate that is wound at a speed of 00 m/min or more, the birefringence at the center of the fiber is 0.09 or less, and the maximum of the small-angle X-ray equatorial scattering curve is 0.02 radian. A polyester fiber for dust-free clothing and a fabric thereof having excellent abrasion resistance, which is characterized by having the following diffraction angles.

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, an inorganic/organic compound for matting, improving dyeability, antistatic, improving hand, and other purposes may be added and mixed and/or copolymerized at a rate of 10% by weight without swirling.

In the polyester fiber 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 or less. This certification is performed as follows.

The small-angle X-ray scattering device is an X-ray generator manufactured by Rigaku Denki (RLI).
-300), using a CuKα ray (1,5418 people) monochromated using a Ni filter as a radiation source, and a goniometer (ON 22035F) manufactured by Rigaku Denki Co., Ltd. for measurement. The scattering intensity in the equator direction is 0 for the first pinhole.
．． 2#φ, second pinhole 0.15 mφ.

The sample is measured by collimation consisting of pspc. The front surface of the pspc probe (effective length 5 crn) has a height of 1 to cut off scattering from directions other than the equator.
Insert a mm horizontal slit. Here, the distance from the sample to the PSPC is 250 m.

Based on the scattering intensity curve measured in this way, an I・82~ε diagram as shown in FIG. 1 is created [I;
: Scattering angle (rad) 1° The fiber of the present invention has this ■・ε2~
A peak or shoulder is observed in the ε curve.

Next, the polyester fiber of the present invention needs to have a birefringence of 0.09 or less at the center of the fiber. This measurement requires C
Birefringence (
Find Δn = n // -n).

A mixture of α-bromnaphthalene and olive oil was used as the immersion liquid. The refractive index distribution was determined by the method of Kjhnle et al.
Omol, Chell, 178.2725 (197
7)], the calculation is performed from the outermost fiber layer.

The birefringence at the center of the polyester 11 of the present invention needs to be as low as described above and the orientation of the molecules should be low, but in order to make the object of the present invention more effective, It is preferable to make the portion amorphous rather than simply having a low orientation. This is true when measuring DSC-temperature curves.
It is certified by observing an exothermic peak due to crystallization.

The polyester 11 fibers of the present invention need to be spun (highly oriented spinning) in a high-speed spinning process that substantially does not include a drawing step, at 6500 m for 7 minutes or more, preferably at 7500 Tn for 7 minutes or more. In a spinning method that involves a drawing process, such as a separate drawing method that involves ordinary spinning and drawing, or a direct drawing method that continuously carries out spinning and drawing, the small-angle X-ray equatorial scattering strong spot curve referred to in the present invention has a maximum. This is not preferred because fibers cannot be obtained.

Furthermore, even in high-speed spinning of 6,500 m/min or higher, the molecular weight of the polyester is set high, the molecular weight distribution is made as sharp as possible, and the pore area of the spinneret is increased.
It is more preferable to appropriately combine measures such as setting a low thirst mark during melt spinning. 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, 6500 m without substantial stretching
It is important that the polyester fiber spun at a speed of 1 minute or more has the specific microstructure described above, and only then can fibers with extremely improved abrasion resistance (fibril resistance) be obtained.

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

The polyester I of the present invention described above! A conventionally known method can be used to weave a dust-free garment fabric using 1Ilt. However, it is necessary that the fiber has no fiber ends, that is, it is long am, and that at least 50% of the polyester fiber of the present invention is used.

<Operations and Effects of the Invention> For comparison, the polyester yarn of the present invention (ω) and the polyester yarn <b+
An abrasion test was conducted on the yarn, and a photograph of the single yarn cut is shown in Figure 2. In the case of +b+, remarkable fibrillation is observed, whereas in the case of (ω), there is little fibrillation, and the shape is more like a fused one.

Furthermore, in an abrasion test under the same conditions, the number of abrasions produced was extremely small compared to the number of fluffs produced in (b).

As described above, the polyester m miscellaneous material of the present invention has excellent fibril resistance that has never been seen before. 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 pikes are 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 1IiN of the present invention is considered to be an aggregate of microfibrils of uniform thickness, 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. It is thought that as a result, macroscopic fibrillation is avoided.

The second reason for the improvement in fibril resistance is that in the case of the polyester fiber of the present invention, the fibril diameter is as thick as 77 Å or more (the peak position in Figure 1 is 0.02 radian or less), so the area of the fibril interface is increased accordingly. is relatively decreasing. Naturally, a reduction in the number of microfibril interfaces is considered to be effective in preventing macrofibrillation.

The third reason why the fibril resistance is improved is that the molecular orientation at the center of the fiber is lowered. The shearing force acting on the fiber surface also propagates to the molecular chains inside the fiber, but the molecular chains in this part are poorly oriented (△n≦0).
．． 09), and furthermore, if there is little crystallization, it is possible that this force is absorbed as deformation of the molecular chains in the center of the fiber. Therefore, polyester 1 with such a higher order structure! In the case of coarse fibrillation, macroscopic fibrillation is suppressed, and at the same time, even when a single filament is cut, the
), it is thought that it does not form into fibrils and takes the shape of a fused structure.

For the reasons mentioned above, the polyester fiber of the present invention has unprecedented fibril resistance, and when used as a dust-free garment fabric, the amount of dust generated from the material can be extremely reduced. Furthermore, in the case of polyester dust-free garment fabrics, modifiers are added for various purposes such as improving hand feel, dyeability, and imparting water absorption properties, and the fabric is often treated with alkali. In such cases, the fibrillation of mm 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.
In terms of fabrics, we can expect improvements in the anti-building (non-fibril anti-building) field.

<Example> Example 1 Polyethylene terephthalate I~ (PET
) The chips were dried at 160° C. for 4 hours and then discharged through a spinneret with 24 circular holes of diameter o, 3 m at a spinning temperature of 285° C. Discharge filament is below the cap 10~9
The 0 cm portion was cooled by cross-blown cooling air at a wind speed of 30 cm/sec, and wound into a winder located 3 m below the spinneret at winding speeds of 5,000 to 9,000 m/min. The filament obtained was 75 de/24 [.

For comparison, after winding at 1500 m/min and 4000 m/min, preheating was 80°C and slit heater temperature was 180°C.
Stretched to 3.2 times and 1.5 times respectively at 75 de/2
A 4fila multifilament was obtained.

120 filaments obtained as above/
After woven into a plain weave fabric with a weft of 106 inches/inch and subjected to normal relaxing scouring and heat setting (180°C x 1 minute), based on JIS-L-0823-1971,
Using a friction tester type ■, load 200g.

The test was conducted under the condition of 5000 reciprocations.

The number of fluffs (single filament breakage) generated and the observation results of the fracture surface using a scanning electron microscope are shown in Table 1, along with the maximum of the equatorial scattering intensity curve of small-angle X-rays and the birefringence of the fiber center.

Table-1 □ In Examples No. 6 and 7, a large amount of fuzz was generated.

Moreover, it splits into thick and long fibrils, making it unsuitable as a fibril-resistant material. These polyester fibers have high birefringence at the center, and no maximum is observed in the small-angle X-ray equatorial scattering intensity curve.

Next, in the case of real INα1 and 2, the occurrence of fuzz is reduced and the abrasion resistance is significantly improved. However, although there are a few
Because the fracture surface is short and split into many fine fibrils, there are concerns about its application to demanding fields such as dust-free clothing. These polyester fibers differ from the polyester fibers of the present invention in that although the maximum is observed in small-angle X-ray equatorial scattering, it is located at a slightly higher angle side, or that the birefringence in the central portion is higher.

On the other hand, in the case of Nα3 to Nα5 of the present invention, the cross section of the jacket shows a fused shape with a small number of fluff, and therefore the polyester fiber material is optimal as a fibril-resistant material.

Example 2 Multifilaments of 75 de/24 ri were obtained in the same manner as in Example 1, except that the intrinsic viscosity of the PET dip was varied. However, the winding speed was fixed at 6,700 m/min. Table 2 shows the miscellaneous structure and wear test results at this time.

Table-2 In the case of implementation Nos. 1 to 3, the occurrence of fluff was relatively large.

These are the fine I! described in the present invention! This is because three structures are not formed in the fiber. On the other hand, implementation No. 4 of the present invention
In No. 6, a unique fiber microstructure was developed, and as a result, the fibril resistance and abrasion resistance were significantly improved.

[Brief explanation of the drawing]

Figure 1 shows the scattering intensity curve of small-angle X-rays in the equator direction (I・ε2
~ε). In the figure (ω is the fiber applicable to the present invention, (b
+ refers to polyester fibers obtained by conventional two-step 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 (field) is the fiber corresponding to the present invention, +b+ is the polyester fiber obtained by ordinary spinning and drawing processes, and (C) is a scaled-down view of the fiber.

Claims (2)

[Claims] (1) A polyester fiber mainly composed of polyethylene terephthalate that is wound at a speed of 6,500 m/min or more without being substantially stretched, and has a birefringence of 0.09 or less at the center of the fiber, and a small angle X The maximum of the line equatorial scattering curve is 0
．． A polyester fiber for dust-free clothing with excellent abrasion resistance, characterized by a diffraction angle of less than 0.02 radians. (2) A dust-free clothing fabric woven from the polyester fiber according to claim (1), which is a long fiber.