JPS6350522A - Production of polybutylene terephthalate yarn - Google Patents

Abstract

PURPOSE:To obtain the titled yarn having improved residual elongation, breaking strength and recovery properties of stretch modulus free from uneven dyeing efficiently without carrying out heat treatment at high temperature, by taking in yarn of polyester consisting essentially of polybutylene terephthalate. CONSTITUTION:A polyester consisting essentially of polybutylene terephthalate is melted, extruded from a spinneret and taken in at 5,500-8,800m/min to give the aimed yarn consisting of undrawn yarn having improved mechanical characteristics of 25-45% residual elongation, 4.2-5.7g/de breaking strength and >=70 % elastic recovery from 15% elongation at room temperature. Undrawn yarn which has no skin-core structure, shows >=230 deg.C melting point and a small-angle X-ray scattered diagram of two points of meridian of >=130Angstrom long period, is desirable.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Application The present invention relates to a polyester back yarn method, more specifically, a mechanical
The present invention relates to a method for using polybutylene terephthalate fibers having excellent F properties, especially elongation elastic recovery properties.

B. Prior Art Polybutylene terephthalate has many excellent properties and is therefore used as a fiber.

In particular, this fiber has strong elongation elasticity, so it is often used as stretch materials such as pantyhose.

Conventionally, this fiber has been spun at a low take-up speed of 1000 m/min, then drawn and heat treated to form a back yarn. According to the # method, K requires heat treatment at a high temperature in order to improve stretch bank properties, which has the disadvantage of high energy cost (and the tendency to cause staining).

C0 Object of the Invention The object of the present invention is to provide a method for efficiently (puring) polybutylene terephthalate fibers having excellent stretch back properties by an extremely simple method.

d1 Structure of the Invention According to the present invention, polyester mainly composed of polybutylene terephthalate is taken at a speed of 5500□ or more and 8800 m or less per minute, and the residual elongation is 25% or more and 45% or less,
Cutting strength is 4.29/de or more 5.7g1/de
Below, the elastic recovery rate from 15X elongation at room temperature is 70
There is provided a method for producing polybutylene ethylene terephthane, which is characterized in that it is made into undrawn fibers having mechanical properties of 5 or more.

The polyester in the present invention is mainly composed of polybutylene terephthalate, but may be a polyester in which each component is replaced with another dispersion component or/and another glyfur component in a proportion of 5 mol % or less. Also io
It may also contain compounds for various purposes such as matting and antistatic purposes, with the z amount being 9 or less.

The unstretched material mainly composed of polybutylene terephthalate of the present invention must have an elastic recovery rate of 70% or more from a 15% elongated state at room temperature, preferably 809 or more. Good! Yes.

If this recovery rate does not reach 709, it is unsatisfactory as a stretchable material.

In the present invention, the elongation elastic recovery rate is measured as follows. In other words, from Tenseen-UTMmMHC manufactured by Toyo Baudouin Co., Ltd., sample length 25 cm + initial load!
-! -g/ae, tensile speed zoX/min, chart feeding speed 20cm/min, after stretching by 15% of the original length, immediately return the clamp at the same speed in the opposite direction, and from the original length when the stress becomes zero. Measure the degree of elongation (16). At this time, the elasticity of extension is 15-! ! Evaluate duplication by □ x 100.

Furthermore, the undrawn polybutylene terephthalate yarn of the present invention has a breaking strength of 482 to 5.7 F/de. Strength is 4
．． If it does not exceed 2 Jl/deK, it is unsuitable for the field of sports clothing, which requires the strongest stretch material.

On the other hand, 5.7 g/de′? : If it is exceeded, there is a disadvantage that the texture of the thread becomes hard.

Further, the polyester fiber of the present invention must have a residual elongation of 25% or more and 45% or less.

When the residual elongation is less than 25%, the toughness of the yarn decreases and the polyester fiber becomes brittle. Further, if the residual elongation exceeds 4596, there is a drawback that the dimensional stability of the polyester fiber is low.

Furthermore, it is preferable that the polyester fiber of the present invention exhibits a melting point of 230°C or higher. If the melting point is not lowered to 230° C., the heat resistance will be low, and there will be problems in terms of sliding abrasion resistance, etc. for use in sports clothing that particularly requires stretch properties. The melting points mentioned here are those of TG- manufactured by Rigaku Denki Co., Ltd.
It refers to the peak temperature of the melting endothermic peak when measured using a DTA standard type in an elementary air flow at a heating rate of 10° C./min.

Polybutylene terephthalate W1 in the present invention. It is preferable that the fibers have substantially no skin core structure.

If a so-called skin core 21 structure is formed in which the surface layer of the fiber has high molecular orientation (and the inner layer has low molecular orientation), good trench back properties cannot be obtained.

In the present invention, the fact that the polyester fibers do not substantially form a Schisophor structure is evaluated as follows. In other words, interference fringes for polarized light with an electric field vector parallel to the fiber axis formed by a transmission type quantitative interference microscope (Inter 7Af manufactured by Carlen Eye Co., Ltd., immersion liquid α-chloronaphthalene I fluid Barafil mixture) are formed at the center of the fiber (
The condition is that it does not show any imperfections.

Figure 1 illustrates a typical pattern of the above-mentioned refractive index interference fringes. is formed.

On the other hand, in case c), the interference fringes do not show a special fringe, and in such cases, the skin core structure is not formed, or even if it is formed, the difference in molecular orientation or crystallinity is (JL ) It is considered to be much smaller than (b).

The polybutylene terephthalate fiber in the present invention preferably exhibits a meridian two-point small-angle Xa scattering image with a long period of 13 OA or more. If the long period is less than 13 OA, and/or another type of scattering other than meridional two-point scattering, such as a four-point interferogram, good stretchback properties cannot be obtained.

The polyester fiber of the present invention basically has a speed of 5500 r/min.
The yarn can be produced by high-speed spinning at r+ or more and 8,800 m or less. If the take-up speed does not reach 5500WsZ, the elongation elasticity will be recovered.

The cutting strength is insufficient and the melting point is also low (on the contrary, 8800
If it exceeds m1 minute, the residual elongation will be low and it cannot be used. In the case of the present invention, it is preferable to use a spinning technique similar to that of a doctor in order to improve the spinning condition.

B) Over a length of 5C1) or more from the bottom surface of the thread cap,
It passes through a heating zone maintained at a temperature of 150° C. or more and 250° C. or less, and then is cooled at room temperature or by a heated air stream.

←) An air nozzle is installed in the darkness of the first take-off device from the spinneret to focus the filament bundle.

The initial take-off device may be a godet ruler or a direct winder. Examples of air nozzles include interlace nozzles and false twist nozzles, and a plurality of these may be used.

(c) A lubricating nozzle guide is used between the spinneret and the first take-up device to collect the filaments while lubricating them. It is preferable that the oil supply nozzle guide be installed downstream of the necking thinning of the filament, and if possible, upstream of the spinning line. %, it is preferable to install it at a point from the end of necking thinning to 10α downstream. Also,
The number of refueling nozzle guides must be limited to one! You may use more than one.

b) The length of the filament running from the spinneret to the initial take-up device is within 4 m.

By the above method, the spinnability at high speed can be significantly improved.

The polystyrene terephthalate undrawn fiber produced by the present invention can be used as it is, but it can also be used at 160°C.
It is a more preferable method to carry out stretching, constant length or relaxation heat treatment by ±20%. In this case, trench bank properties can be further improved.

e9 Functions and Effects of the Invention In the case of the present invention, compared to polybutylene terephthalate fibers that have been spun up to now, it is possible to obtain properties that are superior in stretch puncture resistance, cutting strength, and heat resistance, so it is suitable for sports clothing, etc. extremely suitable.

The reason why the above effects are achieved is considered to be approximately as follows. That is, the polybutylene terephthalate molecule takes the most energetically stable α-deaf conformation (shrinking in the direction of the fiber axis) and the metastable energy-elongated β-deaf conformation. The molecular chain in the α-formation is easily elongated by tension and changes to the β-form conformation, but when the external force is removed, it tends to shrink to the more stable α-form. That is, in the case of polybutylene terephthalate, α.

A strong elongation elastic force is developed due to the reversible formation transition between the layers.

Therefore, in order to further improve the stretch back properties of polybutylene terephthalate fibers, it is necessary to have as many 0-generation formations as possible in the raw yarn. However, in the conventional binding method, Then, since stretching was performed in row 5, there was a problem in that molecular chains in β-type formation that were fully elongated by stretching were likely to occur.On the other hand, by heat treatment, particularly relaxation heat treatment, after stretching, some β-type molecular chains were However, it is still difficult to obtain a sufficient amount of α-dispersed molecular chains.Also, heat treatment requires high temperatures, which increases energy costs and tends to cause staining spots. is unavoidable.

In contrast, in the case of the present invention, the fiber structure is developed during the spinning process.In the case of polyethylene terephthalate, it is known that the H1 fiber structure is formed after a rapid thinning called necking occurs during the high-speed spinning process. However, almost the same phenomenon occurs in the case of polybutylene terephthalate.

When the spinning take-off speed is high, the polybutylene terephthalate molecules are stretched immediately after the completion of Nenking thinning, so the molecular chains tend to take an elongated β-type formation (as in the case of stretching). This is similar to the increase in draw ratio in drawing step iC.However, as the take-off speed increases further, the necking thinning increases further upstream in the spinline, i.e. the formation of the fiber structure takes place closer to the spinneret. It becomes like this.

At the same time, it was recognized that this structure shaping temperature was considerably higher than that of normal spinning or drawing.

As a result of the above, when the spinning take-off speed increases beyond a certain level, polybutylene terephthalate molecules can be oriented and crystallized with an abnormally higher mobility than in the conventional surface yarn method. They started to adopt an α-type hun formation. In other words, when the withdrawal speed exceeds a certain level, α star molecules, which are the most stable in terms of energy but have a shrunken form, begin to increase. This phenomenon has not been observed in conventional high-speed spinning, and is a major feature of the present invention.

The polybutylene terephthalate fiber of the present invention has good strength. Normally, in such ultra-high speed spinning, although the molecular orientation of the fiber surface layer becomes high, the orientation of the fiber center decreases. As the take-up speed increases, the structural difference in the skin fiber structure increases significantly.As a result, the mechanical bone properties of the ultra-high speed spun fibers deteriorate significantly.

However, in the trap of the present invention, crystallization progresses and ends in an extremely short period of time. Therefore, the skin fur structure does not occur and the mechanical
It is assumed that sex will not deteriorate either.

Furthermore, the present invention exhibits better heat resistance than conventional polyester fibers. This is because, as mentioned earlier, in the case of the present invention, crystallization occurs at a higher temperature and higher mobility, so the crystal size is thicker (the crystal size is larger, the surface energy is relatively lower, and the α-type is energetically stable). This is explained by the fact that the melting point increases significantly due to the formation of crystals.

f, Examples Example 1 The intrinsic viscosity is 0.80, and titanium oxide is used as a matting agent.
．． 3 Polybutylene terephthalate containing X (PBT)
After drying the chips at 160°C for 4 hours, 12 circular holes with a diameter of 0.35 mm were made, and the chips were discharged from a spinneret kept at 285°C and spun at high speed at a take-up speed of 5,500 m/min to 8,800 m/min. A multifilament of 37.5 denier/12 filaments was obtained. At this time, the base is 151
During this period, the atmosphere surrounding the running yarn is heated to 180°C, and then cooling air at room temperature (wind speed: 12 e
x/sec] to cool the area from 20 cx to 90 degrees below the mouthpiece.

Further, the winding machine was installed at the position of the spinneret 3FPI, and the yarn was wound directly onto the winding machine without going through a godet ruler.

In addition, we used an infrared diameter control device made by Zimmer.
Measure the thickness of the running filament in a non-contact state, determine the point where necking has finished, and the point where the fiber diameter is the same as the winding weir 9 fiber, and install a metering oil nozzle guide downstream of it at 5α. , the filament was focused, rapidly cooled, and refueled at the same time.

The strength of the polybutylene terephthalate fiber obtained as described above, the elastic recovery rate at 15X elongation, the F&i point,
Small-angle X-ray scattering image, long-period summary is shown in Table 1.

Table 1 These samples all have good strength 9 elastic recovery rate,
It has a high melting point and moderate elongation. All of these show small-angle X-ray images of meridian two-point scattering, and the long period is 130.
Become A or higher.

Comparative Example 1 A back yarn was produced in the same manner as in Example 1 except that the spinning speed was 5000 m/min and 9000 m/min. The results are shown in Table 2.

Atsushi 2 In the case of Oni 6, the strength is rather low and the elongation is large. Also, the elastic recovery rate is insufficient. On the other hand, Arashi 7 has little residual elongation and is problematic as a trench material.

Comparative Example 2 The same polymer as in Example 1 was used, and after winding with a normal spinning machine at a spinning speed of 1800 yn/min, the preheating temperature was 80°C, and the stretching ratio was 2, 3. It was stretched with a slit heater at 180°C to obtain a polybutylene terephthalate fiber of 37.5 de/12 fi/ as in Example 1. The results at this time are shown in Table 3.

Table 3 In this case, the elastic recovery rate is low and the purpose as a stretch material cannot be achieved.

Example 2 Example 1. Samples of Na3 were heat treated at various stretching and relaxation rates using two rollers and a 200°C plate heater installed between them. The elastic recovery rate at this time is shown in Table 4.

Table 4 In this case, a further improvement in hair extension elasticity was observed for Na1O to Na14.On the other hand, for Magnets 9 and 15, it deteriorated compared to the original sample.

[Brief explanation of the drawing]

FIG. 1 is an exemplary diagram of a refractive index interference fringe pattern.

Claims (5)

[Claims] (1) Polyester mainly composed of polybutylene terephthalate is taken at a speed of 5,500 m or more and 8,800 m or less per minute, with a residual elongation of 25% or more and 45% or less, and a cutting strength of 4.2 g/de or more and 5.7 g/de. Below, 15 at room temperature
A method for producing polybutylene terephthalate fiber, which is characterized in that it is an undrawn fiber with excellent mechanical properties such that the elastic recovery rate from a stretched state is 70% or more. (2) The method for producing polybutylene terephthalate fibers according to claim (1), in which the undrawn fibers do not substantially have a skin-core structure. (3) The method for producing polybutylene terephthalate fibers according to claim (1) or (2), in which the undrawn fibers have a melting point of 230°C or higher. (4) The undrawn fiber exhibits a meridian two-point small-angle X-ray scattering image with a long period of 130 Å or more.
) or (3), the method for producing polybutylene terephthalate fibers. (5) Claim (1), wherein the undrawn fiber has an elastic recovery rate of 80% or more from a 15% elongated state at room temperature;
The method for producing polybutylene terephthalate fiber according to item (2), item (3) or item (4).