JPS5828371B2 - Polyester polyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyester crimped yarn that does not produce spot-like local gloss when made into a woven or knitted fabric.

In recent years, a method has been implemented to produce crimped yarn by false-twisting undrawn polyester yarn at the same time as drawing, but the crimped yarn produced by this method suffers from deformation of the filament cross section due to the simultaneous stretching and false-twisting. Due to the severe flattening, there is a problem in that the crimped yarn woven or knitted fabrics woven or knitted with this material have a localized luster (flicker), which makes them difficult to use for outerwear, especially for men's clothing. The disadvantage is that it is not suitable for this field.

In order to solve this drawback, a method has been proposed in which the filament cross section is non-circular, such as triangular, square, or pentagonal, using as the undrawn yarn.
No. 9-26554, JP-A-49-36950).

However, even if the filament cross section of the undrawn yarn is made into an irregular cross section as described above, it is difficult to completely prevent flickering of the crimped yarn woven or knitted material.

Moreover, when a thread with an irregular cross section is used, light rays are reflected diffusely on the surface of the filament, so that the color tone of the dyed product becomes unclear, resulting in a so-called "pastel tone".

Furthermore, undrawn yarns with triangular, square, pentagonal, etc. cross-sectional filament shapes have a more uniform molecular orientation than ordinary yarns with circular cross-sections even at the same spinning speed, and therefore the stretching ratio in simultaneous stretching and false twisting is lower. , productivity decreases.

In addition, these undrawn yarns have a smaller silk factor than ordinary circular cross-section yarns, and tend to break or fluff during processing, and the strength and elongation properties of the crimped yarns in the product tend to be poor.

As a result of repeated research in order to eliminate the above-mentioned drawbacks of the conventional method, the present inventors have found that by making the cross-sectional shape of the filament of the undrawn yarn into a special heptalobal shape, such drawbacks are eliminated and good crimping is achieved. It was discovered that threads can be obtained, and the present invention was achieved.

That is, in the present invention, when producing a crimped yarn by simultaneously drawing and false-twisting an undrawn polyester yarn, the undrawn yarn has a filament having a heptalobal cross-sectional shape with seven protrusions; The ratio of the radius 4 of the circumscribed circle and the radius (r) of the inscribed circle of the heptalobal shape is 1.05-1.16
It is characterized by using undrawn yarn.

The undrawn polyester yarn as used in the present invention is a general term for undrawn multifilament yarn made of polyester containing 80 mol% or more of ethylene terephthalate units.

The undrawn yarn may be a completely undrawn yarn spun at a spinning speed of 2500 m/min or less, or a spinning speed of 2500 to 400 m/min.
It may also be partially oriented yarn (POY) spun at 0 m/min.

These undrawn yarns may contain a matting agent such as titanium oxide, but the content of titanium oxide is smaller than that of normal dull yarns or semi-dull yarns (i.e. 0.10 to 0.35% by weight). It is preferable to do so because the color tone of the dyed product becomes clearer.

The single yarn denier of the undrawn yarn is preferably 2 to 7 de, especially 2 to 5 de as the single yarn denier after stretching, and the total denier is 30 to 300 de, especially 40 de as the denier after stretching.
~160 de is preferred.

In the present invention, as the undrawn filament, a filament having a heptalobal cross-sectional shape having seven protrusions is used.

This cross-sectional shape has the advantage that the filaments are not packed closely during false twisting, and the friction between the filaments during false twisting is small, resulting in good processing conditions and less generation of fluff.

In the present invention, in the heptalobal shape having the seven protrusions, when the circumscribed circle and inscribed circle are drawn, the ratio (R/r) of the radius of the circumscribed circle and the radius of the inscribed circle (r) 1.0
5 to 1.16.

R/r can be set within the above range by selecting the shape of the spinning hole and the cooling conditions for the spun yarn in the spinning process.

FIG. 1 is an enlarged cross-sectional view for explaining the filament cross-sectional shape of the undrawn yarn used in the present invention, R in the figure is the radius of the circumscribed circle, and r is the radius of the inscribed circle.

When the ratio of R to r (R/r) is less than 1.05, flickering of the crimped yarn woven or knitted material increases, and the winding property in the spinning process decreases, resulting in a decrease in the maximum winding amount.

On the other hand, when R/r exceeds 1.16, the color tone of the dyed product becomes unclear and becomes pastel-like.

Furthermore, when R/r is larger than 1.16, the drawing ratio of the undrawn yarn decreases when compared at the same spinning speed, resulting in poor productivity, which is not preferable.

Figure 2 shows polyethylene terephthalate at 3500 m.
Regarding the heptalobal cross section POY of 2 20 de/ 48 fil spun at /min, the above R/r and flicker,
It is a graph showing the results of examining the relationship between pastelization and spinning winding condition (maximum winding amount).

It can be seen from FIG. 2 that the R/r is preferably within the range of 1.05 to 1.16.

In addition, in the above example, the sizes of the seven protrusions are approximately the same,
The intervals between the respective protrusions are also approximately equal, but the sizes and/or intervals of the seven protrusions do not necessarily have to be the same.

For simultaneous drawing and false twisting of such undrawn yarns having a heptalobal cross section, normal conditions can be used. For example, in the case of undrawn yarns with a spinning speed of 2800 to 3500 m/min, the draw ratio is 1.3. ~1.8, heat set temperature 1
Conditions of about 60 to 220°C are suitable.

As the false twisting means, a false twisting spindle is generally used, but a circumscribed or internal friction type may also be used.

In the polyester crimped yarn obtained by the method of the present invention as described above, even if the cross-section of the filament is deformed (flattened), the deformed cross-section of the filament has many protrusions, which causes local reflection. There are no flat areas,
There are almost no flickers in crimped yarn woven or knitted fabrics.

Moreover, there is very little pastelization of color tone due to diffused reflection, and dyed products with clear color tone can be obtained.

Furthermore, the processing condition of the simultaneous stretching and simultaneous false twisting process is good, and a crimped yarn with less fuzz and excellent physical properties can be obtained.

Further, the undrawn yarn having the cross-sectional shape specified in the present invention can be wound stably even at high speed winding (for example, 2500 m/min or more), and the maximum winding amount can be increased.

Example Intrinsic viscosity (measured at 35°C in 0-chlorophenol) is 0
．． 635 polyethylene terephthalate (TiO2 content: 0.3% by weight) was melt spun and wound at a speed of 3500 m/min.

At this time, a spinneret having 48 spinning holes with seven slits radially drilled from the center was used, and the cooling conditions of the spun yarn were variously adjusted to create four heptalobal shapes with different R/r. A cross-sectional undrawn yarn was produced.

These undrawn yarns, circular cross-section undrawn yarns, and trilobal cross-section undrawn yarns spun using a separate spinneret were subjected to drawing and simultaneous false twisting under the following conditions to obtain crimped yarns (
150de/48 fil) was produced.

Next, woven fabrics were produced using each of the crimped yarns and dyed dark blue under the following conditions, and the degree of flicker and pastel tone was visually determined.

The results are shown in Table 1.

Stretching and simultaneous false twisting processing conditions Stretching ratio: 1469 times Heat setting temperature: 190°C Number of twists: 650 T/M* *Processing speed: 50 m7 minutes Dyeing conditions: Dye: Amacron Iue LS Temperature: 1.0%oWf Bath ratio: 1:0 Temperature: 0 hours■ 30℃×60 minutes

[Brief explanation of drawings]

Fig. 1 is an enlarged view for explaining the filament cross-sectional shape of the undrawn yarn used in the present invention, and Fig. 2 is an enlarged view of the undrawn yarn used in the present invention.
It is a graph showing the relationship between r, winding condition (indicated by maximum winding amount), and flickering and pastelization in a crimped yarn fabric. In the figure, the solid line indicates the maximum amount of winding, the dashed line indicates flickering, and the dotted line indicates pastelization.

Claims (1)

[Claims] 1. When producing a crimped yarn by drawing and simultaneously false-twisting an undrawn polyester yarn, the undrawn yarn has a filament whose cross-sectional shape is a heptalobal shape with seven protrusions, and the circumference of the heptalobal shape. Production of polyester crimped yarn characterized by using undrawn yarn having a ratio (R/r) of the radius of the circle (R) to the half set r) of the inscribed circle of 1.05 to 1.16. Law.