JPH06101115A - Method for drawing and heat-treating undrawn polyester-based yarn bundle - Google Patents

Abstract

PURPOSE:To readily produce a polyester fiber, having high strength, low elongation and low heat shrinkage properties and suitable as machine sewing thread and industrial fabrics with good operating efficiency. CONSTITUTION:An undrawn polyester yarn bundle having >=1000000 denier is heat-treated by arranging a superheated steam treating device in the final drawing zone and subsequently drawn by heating draw rollers in the final drawing zone and the drawn yarn bundle is then subjected to relaxing heat treatment by installing a superheated steam treating device in the relaxing heat treatment zone in drawing the undrawn polyester yarn bundle at >=3.8 times total draw ratio according to a multistage drawing method of >=2 stages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretching heat treatment method for an unstretched yarn bundle for producing a polyester fiber suitable for sewing threads and industrial fabrics.

[0002]

2. Description of the Related Art Polyester fibers, especially polyethylene terephthalate fibers, have many excellent properties and are widely used in various applications including woven and knitting applications for clothing. However, for sewing threads and industrial fabrics, how many methods can be used to produce a polyester fiber that requires high strength, low elongation and low heat shrinkability by stretching a polyester unstretched yarn bundle with a fineness of 1 million denier or more, for example? However, a method for stably producing a polyester fiber satisfying all these characteristics with high productivity has not been proposed yet.

For example, Japanese Patent Laid-Open No. 48-73513 discloses 100
Stretching is started with heat of moisture below ℃, and 100 ℃ before stretching is completed.
A method of performing a one-stage drawing heat treatment with the above-mentioned saturated steam has been proposed, but since this method draws in one stage, 8.0 g
It is difficult to obtain a fiber having a strength of / d or more, and since heat treatment is performed at the same time as drawing, a fiber having low heat shrinkability cannot be obtained. Also,
Even if high-strength fibers are obtained, there is a problem in that the yarn bundle is often wound around the roller, resulting in poor operability.

Further, in Japanese Examined Patent Publication No. 47-2065, an undrawn yarn bundle is drawn in a liquid bath so that the density becomes 1.365 g / cm ³ or less in the first stage, and then this is drawn in the second stage with a density of 1.365. A method of steam-bath stretching with steam so as to achieve g / cm ³ or more has been proposed, but with this method, the stretching ratio must be increased in the second stage, and the yarn winding around the roller increases. There was a problem of poor operability.

Further, in Japanese Unexamined Patent Publication No. 57-161136, unstretched yarn bundles are stretched in two stages at a high stretch ratio, subjected to relaxation heat treatment, and subsequently subjected to extension heat treatment and then heat treated in a freely shrinkable state. A method has been proposed. This method has low elongation,
Although a fiber having low heat shrinkability is obtained, there is a problem that tension is increased during the extension heat treatment and yarn breakage easily occurs because the relaxation heat treatment and the extension heat treatment are performed after the multi-stage drawing.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and makes it possible to stably produce polyester fibers having high strength, low elongation and low heat shrinkability with high productivity. It is a technical object to provide a method for drawing heat treatment of a drawn yarn bundle.

[0007]

The present inventors have arrived at the present invention as a result of earnest research for solving the above problems.

That is, according to the present invention, when a polyester-based undrawn yarn bundle having a fineness of 1 million denier or more is drawn to a total draw ratio of 3.8 times or more by a multi-step drawing method of 2 steps or more, a superheated steam treatment is applied to a final drawing area. The temperature of the jet steam in the superheated steam processor is 115 to 160 ° C, and the amount of jet steam is 150 to 35
0 m ³ / H, the yarn bundle residence time is 1 second or more, and the draw roller in the final stage drawing area is heated to 150 to 220 ° C. and drawn, and then superheated in a relaxation heat treatment area equipped with a superheated steam processor. The temperature of the jetted steam in the steam processor is 180 to 230 ℃, the amount of jetted steam
A method for stretching heat treatment of a polyester-based unstretched yarn bundle, characterized by subjecting a yarn bundle after stretching to a relaxation heat treatment of 3% or more with 150 to 500 m ³ / H and a residence time of the yarn bundle of 1 second or more. Is.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic process diagram showing one embodiment of the present invention, which is an example of two-stage stretching.

The undrawn yarn bundle Y is drawn through the first stage while passing through the hot water bath 7 between the feed roller 1 and the first draw roller 2, and then the first draw roller 2 and the second draw roller 2 are drawn. While passing through the superheated steam processor 5 with the draw roller 3,
The second stage drawing is performed. Next, the drawn yarn bundle is subjected to a relaxation heat treatment while passing through the superheated steam treatment device 6 between the second draw roller 3 and the take-up roller 4 to obtain high strength, low elongation, and It becomes a low heat shrinkable polyester fiber.

In the present invention, the total draw ratio in multi-stage drawing must be 3.8 times or more, more preferably 4.0 times or more. If it is less than 3.8 times, fibers with high strength and low elongation cannot be obtained. In addition, the draw ratio of the first stage is 2.6
It is particularly preferable to set the draw ratio to ˜3.5 times and the draw ratio of the second and subsequent steps to 1.1 to 1.5 times in order to reduce the winding of the yarn bundle on the rollers and draw with good operability.

Next, the first stage stretching performed between the feed roller 1 and the first draw roller 2 may be either dry type or wet type, but the wet stretching using a hot water bath or the like has a fixed stretching point. It is preferable because it is easily processed.

The stretching of the second and subsequent stages and the stretching of the final stage before the relaxation heat treatment are performed between the draw rollers, but it is necessary to heat the final draw rollers to 150 to 220 ° C. in order to relieve shrinkage stress. is there. If the heating temperature is lower than 150 ° C., the shrinkage stress cannot be sufficiently relaxed, and if the heating temperature exceeds 220 ° C., thermal embrittlement of the fiber starts and the physical properties of the fiber deteriorate, which is not preferable.

In the present invention, it is necessary to install the superheated steam processor 5 in the final drawing area for drawing. When a contact-type heat plate is used instead of the superheated steam processor 5, rubbing occurs between the heat plate and the yarn bundle, fluffing occurs, which causes roller wrapping. The drawn yarn bundle is not heated uniformly, which makes it impossible to perform high-magnification drawing, which is not preferable.

The jet steam temperature in the superheated steam processor 5 is 115
~ 160 ℃ is necessary, preferably 120 ~ 150 ℃
Is. If the temperature is lower than 115 ° C, the temperature of the yarn is not sufficiently raised, and uniform heating cannot be performed, so that yarn breakage is likely to occur and the operability during drawing is significantly reduced. If the temperature is higher than 160 ° C., the crystal part of the fiber is heat-set, so that it cannot be stretched at a high magnification, fluff is often generated, and the operability at the time of stretching is remarkably reduced, which is not preferable.

The amount of steam ejected in the superheated steam processor 5 is 150-
It should be 350m ³ / H. If it is less than 150 m ³ / H, the yarn bundle cannot be heated sufficiently uniformly, so that yarn breakage occurs and the operability during drawing is significantly reduced. Further, if it exceeds 350 m ³ / H, the size of the device must be increased, or a plurality of devices must be used, which is not preferable because the cost becomes high.

The residence time of the yarn bundle in the superheated steam processor 5 is 1
It is necessary to set it to 2 seconds or more, preferably 2 to 5 seconds. If the residence time is less than 1 second, sufficient heat cannot be transferred to the yarn bundle, and yarn breakage easily occurs, so that high-strength, low-elongation fibers cannot be obtained. The residence time may exceed 5 seconds, but if it is about 5 seconds, the effect of heat transfer is sufficient, so there is no point in making it longer.

Superheated steam processor 5 used in the final stage drawing zone
Has a length of 3000 mm or more and a width of 900 mm or more. If the length is less than 3000 mm, the yarn bundle retention time is unlikely to be 1 second or longer, and it is possible to make the yarn bundle retention time 1 second or longer by lowering the drawing speed, but the productivity is significantly reduced. It is not preferable. Further, if the width is less than 900 mm, the width of the yarn bundle at the time of drawing is regulated, which lowers productivity, which is not preferable.

In the present invention, after the yarn bundle is drawn in the final stage drawing zone, the draw roller 3 in the final stage is used in order to stabilize the physical properties such as high strength and low elongation and to improve the dimensional stability during heating. Although the relaxation heat treatment is performed between the take-up roller 4 and the take-up roller 4, the relaxation heat treatment needs to be performed using the superheated steam processor 6.

In this case, the temperature of the jetted steam in the superheated steam processor 6 disposed in the relaxation heat treatment area is 180 to 230 ° C., the jetted steam amount is 150 to 500 m ³ / H, and the yarn bundle retention time is 1 second or more. The subsequent yarn bundle is subjected to relaxation heat treatment of 3% or more.

When the temperature of the jetted steam is less than 180 ° C., the dimensional stability during heating, especially during dyeing and finishing of the fiber, deteriorates, and heat treatment at a temperature over 230 ° C. causes thermal embrittlement of the fiber. Therefore, the physical properties of the fiber, particularly the strength, are significantly reduced and the fiber cannot be put to practical use.

The superheated steam processor 6 may be of the same shape as the one used in the final stage drawing zone. In order to sufficiently relax the yarn bundle, the jet in the superheated steam processor 6 may be used. The above amount should be 150-500m ³ / H. When the residence time of the yarn bundle in the superheated steam processor 6 is less than 1 second, the yarn bundle is not sufficiently heat-treated, so that the heat shrinkage rate of the obtained fiber is high, and even if the relaxation rate is less than 3%, the heat shrinkage rate is low. This is not preferable because the above fiber cannot be obtained.

It is not always necessary to heat the take-up roller 4 in the relaxation heat treatment region, but if a heating roller is used, the physical properties such as high strength and low elongation of the fiber are stabilized and the dimensional stability during heating is further improved. You can The preferable heating temperature when the heating roller is used is 150 to 220 ° C., and if it exceeds 220 ° C., thermal embrittlement of the fiber begins and physical properties deteriorate, which is not preferable.

The polyester fiber in the present invention has polyethylene terephthalate as a main constituent,
Copolymerized with a third component such as isophthalic acid, 5-sodium sulfoisophthalic acid, paraoxybenzoic acid, diethylene glycol, triethylene glycol, 1,4-butanediol, etc., provided that the properties are not essentially changed. Alternatively, it may contain a small amount of additives such as a matting agent, a coloring agent, a stabilizer, a flame retardant, and a moisture absorbent.

In the present invention, the fineness of the polyester type undrawn yarn bundle serving as the supply yarn is required to be 1 million denier or more because productivity decreases as the fineness decreases. The upper limit of the fineness of the polyester-based undrawn yarn bundle is not particularly limited, but if the fineness is too large, the load on the drawing machine increases and high-magnification drawing becomes difficult, so it may be set to 5 million denier or less. preferable.

[0026]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In addition, the measuring method of the physical property in an Example is as follows. Fineness: Measured by the method of JIS L-1015-7-5-1A. Strength: Measured by the method of JIS L-1015-7-7. Elongation: Measured by the method of JIS L-1015-7-7. Strength: A value obtained by dividing the strength value by the fineness of a single yarn. Dry heat shrinkage: Measured with a load of 300 mg per denier by the method of JIS L-1015-7-15. Intrinsic Viscosity: Measured at 20 ° C. using a mixed solution of phenol, ethane tetrachloride and the like as a solvent by weight.

Examples 1 to 7 and Comparative Examples 1 to 9 Polyethylene terephthalate having an intrinsic viscosity of 0.65 was passed through a spinneret having a spinning temperature of 295 ° C., a hole diameter of 0.27 mm and a number of holes of 1450.
Melt spinning was performed at 00 m / min to obtain an undrawn yarn of about 140,000 denier. Next, the obtained undrawn yarn was combined into a yarn of about 2.8 million denier to obtain an undrawn yarn bundle. Using the stretching heat treatment apparatus shown in FIG. 1, each of the obtained unstretched yarn bundles was heated to the temperature shown below to perform two-stage stretching, and then in the relaxation heat treatment zone in the superheated steam treatment device. The amount of steam
After the relaxation heat treatment at 350 m ³ / H and crimping, the fineness is
A 700,000 denier yarn bundle was cut to obtain short fibers with a cut length of 44 mm. The speed of the take-up roller 4 at this time was 120 m / min, various other manufacturing conditions are shown in Table 1, and the evaluation results of the physical properties and operability of the obtained short fibers are shown in Table 2. Feed roller 1 temperature: 68 ℃ Hot water bath 7 temperature: 70 ℃ 1st draw roller 2 temperature: 60 ℃ 2nd draw roller 3 temperature: 200 ℃ Take-up roller 4 temperature: 200 ℃

[0028]

[Table 1]

[0029]

[Table 2]

In Examples 1 to 7, fibers having physical properties of high strength, low elongation and low heat shrinkage could be obtained with good operability.
On the other hand, Comparative Example 1 in which the superheated steam treatment device is not used in the final stage drawing region and the relaxation heat treatment region, and Comparative Examples 2, 5 in which the jetted steam temperature or the yarn bundle retention time in the final stage drawing region is insufficient
Then, thread breakage occurred frequently and operability was poor. Comparative Example 4 in which the superheated steam treatment device does not perform treatment in the relaxation heat treatment zone and Comparative Example 7 in which the temperature of the jetted steam is insufficient in the relaxation heat treatment zone
The fiber had high strength and low elongation, but had high dry heat shrinkage. In Comparative Example 3, since the temperature of the jetted steam in the final drawing region was higher than the crystallization temperature, the fiber was thermally embrittled and the yarn was broken, resulting in poor operability. In Comparative Example 6, the temperature of the jetted steam in the relaxation heat treatment region was too high, thermal embrittlement occurred, and yarn breakage occurred. In Comparative Example 8, the fiber having high strength and low elongation was not obtained because of the low draw ratio, and in Comparative Example 9, the fiber having low heat shrinkage was not obtained because the relaxation rate after stretching was less than 3%. .

[0031]

EFFECTS OF THE INVENTION According to the present invention, a yarn bundle can be heated efficiently and uniformly by using a superheated steam treatment device, and since it is a non-contact type, fluffing due to rubbing does not occur and high-magnification drawing is possible. This makes it possible to stably and stably produce polyester fibers having high strength, low elongation and low heat shrinkability.

[Brief description of drawings]

FIG. 1 is a schematic process diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Feed Roller 2 1st Draw Roller 3 2nd Draw Roller 4 Take-up Roller 5 Superheated Steam Processor 6 Superheated Steam Processor 7 Hot Water Bath Y Unstretched Yarn Bundle

Claims (1)

[Claims] 1. A total draw ratio of a polyester-based undrawn yarn bundle having a fineness of 1 million denier or more by a multi-stage drawing method of 2 or more steps.
When stretching to 8 times or more, place a superheated steam processor in the final stage stretched area and adjust the temperature of the jetted steam in the superheated steam processor.
115 to 160 ° C., jetting amount of steam 150 ~350m ³ / H, the yarn bundle residence time was 1 second or more, and a draw roller in the final stage stretching zone
After heating to 150-220 ℃ and stretching, in the relaxation heat treatment area where the superheated steam processor is arranged, the temperature of the steam discharged in the superheated steam processor is 180-230 ℃, the amount of steam discharged is 150-500 m ³ / H, A method for stretching heat treatment of a polyester-based undrawn yarn bundle, which comprises subjecting a yarn bundle after drawing to a relaxation heat treatment of 3% or more with a yarn bundle residence time of 1 second or longer.