JP2001262435A - Undrawn fiber, drawn fiber and method for producing the same - Google Patents

Abstract

(57) [Summary] (Corrected) [Solution] Unstretched polytrimethylene terephthalate fiber (unstretched PTT fiber) satisfying the following (1) and (2). (1) Birefringence of undrawn fiber ≦ 0.06 (2) Average moisture content of undrawn fiber ≦ 2% by weight After winding up the undrawn fiber, polytrimethylene obtained by drawing it Terephthalate drawn fiber (PTT drawn fiber) drawn fiber. A two-stage method for producing the drawn fiber. [Effect] Polytrimethylene terephthalate (PTT)
In a two-stage method for producing fiber, PTT for clothing with high uniformity, in which irregularity of the drawing condition and fineness of the drawn fiber are suppressed.
Fiber can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an undrawn fiber, a drawn fiber comprising polytrimethylene terephthalate fiber, and a method for producing the same. More specifically, unstretched fiber, which is an intermediate product in a so-called two-stage manufacturing method, in which polytrimethylene terephthalate is melt-spun, wound once as an unstretched fiber, and then stretched to produce a fiber, is used. And a method for producing the same. More specifically, it relates to a highly uniform drawn polymethylene terephthalate fiber for clothing, an undrawn fiber from which the fiber can be obtained, and a method for producing the same.

[0002]

2. Description of the Related Art Polyethylene terephthalate fiber (hereinafter referred to as "PET fiber") is produced in large quantities worldwide as a synthetic fiber most suitable for use in clothing, and has become a major industry. On the other hand, polytrimethylene terephthalate fiber (hereinafter referred to as "PTT fiber") has a long history of research,
Conventionally, the price of trimethylene glycol, one of the raw materials, is high, and has not yet reached full-scale industrial production. However, in recent years, an inexpensive process for producing this trimethylene glycol has been developed, and the possibility of industrialization has emerged. PTT fiber is expected to be an epoch-making fiber having both the advantages of polyester fiber and nylon fiber, and its characteristics are being considered for application to clothing and carpets.

[0003] PTT fibers are described in (A) Pol
ymer Science: Polymer Phils
ics Edition Vol. 14 P263-2
74 (1976) and (B) Chemical F
ibers International Vol. 4
5, April (1995) 110-111, (C) JP-A-52-5320, and (D) 58-10421.
No. 6, (E) No. 52-8123, (F) No. 5
Prior arts, such as Japanese Patent Application Laid-Open No. 2-8124 and (G) WO99 / 27168, are already known.

The prior arts (A) and (B) describe the basic properties of stress-elongation properties of PTT fibers,
It has been suggested that the TT fiber has a small initial modulus and excellent elastic recovery, and is suitable for use in clothing and carpets. Further, in the prior arts (C) to (G), in order to further improve such characteristics of the PTT fiber, there has been proposed a method of improving the dimensional stability against heat and further improving the elastic recovery. In these prior arts, most of them are based on 2 methods for producing PTT fibers.
Manufactured by a step process. Among them, the following technology is disclosed in the prior art (D) which is technically similar to the present invention.

[0005] Unstretched PTT fiber by a usual production method,
That is, the unstretched fiber spun at a spinning speed of less than 2000 m / min has an extremely low degree of orientation and crystallinity, and a low glass transition temperature of 35 ° C., so that the change with time is extremely fast, and fluffing and It is difficult to obtain PTT fibers having good properties due to frequent NEPs. In the prior art (D), as a technique for avoiding this problem, the spinning speed is set to 2000 m / min or more, preferably 2500 m / min or more, the degree of orientation and crystallinity of the fiber is increased, and the drawing temperature is 35 to 80. A method of keeping the temperature in ° C has been proposed. Further, the prior art (D) discloses an example in which an undrawn fiber is obtained at a spinning speed of 3500 m / min or more, left at a temperature of 20 ° C. and a humidity of 60% for 24 hours, and then drawn.

However, in the prior art (D), 2000 m /
It is described that the structure and physical properties of the undrawn fiber spun at a spinning speed of less than one minute are so-called time-dependent changes that change with time near room temperature, and that this directly affects the drawing condition, There is no mention or suggestion of a workaround. Furthermore, there is no suggestion about a specific means for minimizing the change over time and providing a good drawing condition and a good fiber quality. From the description of the examples of the prior art (D), the PTT drawn fibers obtained by the method (D) are as follows:
It can be seen that the PTT fiber has a toughness of 18 (cN / dtex)% ^1/2 or less and has poor mechanical properties.
In the comparative example of the prior art (D), it is described that the fiber was spun at a spinning speed of 1200 m / min, and the undrawn fiber was allowed to stand in an atmosphere at 20 ° C. and a relative humidity of 60% and then drawn. Only a fiber having a value as low as 0.6 (cN / dtex)% ^1/2 was obtained, and there was no description about the fineness variation value U% or the periodic variation.

[0007]

In the production of PTT fibers by the two-step method, the shape of the undrawn fiber package changes with time due to shrinkage or drying, and the package is wound around such a time-varying package. The drawn fiber obtained from the drawn undrawn fiber generally has a large fineness variation value, that is, U%,
In addition, a periodic fineness variation corresponding to the product of the traverse width of the undrawn fiber winder or a multiple thereof and the actual drawing ratio occurs. This periodic fineness variation is detected in a sawtooth shape on the low fineness side and the high fineness side. FIG. 1 shows an example of a continuous fineness variation measurement chart using Evenness Tester. What is periodic fineness variation?
The fluctuation corresponds to the whisker-like signals existing at equal intervals on the chart of FIG. The fact that signals are observed at equal intervals means that the fineness variation that causes signal generation occurs periodically, and the presence of a strong downward signal indicates that the fineness of that point in the fiber length direction (Fiber thickness) is fluctuating to the lower side. Also, the presence of a strong upward signal
This means that the fineness at that point in the fiber length direction fluctuates to the higher side.

The interval of occurrence of the periodic fineness fluctuation is substantially equal to the unstretched fiber length for one stroke × actual stretching ratio between the both ends of the unstretched fiber package, or the unstretched fiber length for two strokes × actual stretching. Equivalent to the ratio. In the two-stage method, the occurrence of the periodic fineness fluctuation is determined by the stroke length, the twill angle, and the drawing ratio of the winding machine of the undrawn fiber package, but is usually 10 m or less. As described above, a drawn fiber having a large fineness variation value U% and having a periodic fineness variation has generally poor dyeing uniformity when dyed after forming into a knitted fabric, and exhibits periodic spots and gloss spots. It is not suitable for apparel applications that respect uniformity.

FIG. 2 shows an example of a measurement chart of an evenness tester in which this periodic fluctuation does not exist. The present inventors have proposed, as one method for solving such a problem, a proposal for specifying a winding tension at the time of winding an undrawn fiber, a storage of the undrawn fiber, and management of temperature and humidity in a drawing process. 11-0
No. 68672. According to this proposal, the temporal deformation of the undrawn fiber package shape is eliminated, and as a result, the periodic fineness fluctuation and toughness appearing on the low fineness side of the drawn fiber are improved.

Usually, in the industrial production of synthetic fibers by the two-stage method, after winding unstretched fiber having a weight of 5 to 10 kg, it is passed through a lag time into a stretched fiber pan having a winding volume of 2 to 3 kg for 2 to 5 times. I'm taking. In the sorting operation of the undrawn fibers into the drawn fibers, the threading operation is performed on the entire weight only for the first time, and the subsequent sorting is called “intermediate switching”, and the threading operation is omitted and only the replacement of the pan is performed. Then, at the time of the "intermediate switching", a stretching pin is employed to suppress yarn breakage at the start of stretching.
In the case of industrial production, 4 times from unrolled winding to the end of stretching.
It can take up to 5 days.

In the case where the drawing is performed by using a drawing pin when drawing the undrawn fiber or when the lag time until drawing exceeds about 100 hours, the periodic fineness is not changed by using the above-mentioned proposal alone. Fluctuations have emerged and it has proved difficult to achieve its purpose completely. Furthermore, it became clear that the periodic fineness variation appears not only on the low fineness side but also on the high fineness side. In addition, it has become clear that stretching under such conditions cannot be eliminated anymore simply by increasing the birefringence as disclosed in the prior art (D).

Therefore, an object of the present invention is to provide a PTT fiber 2
An object of the present invention is to provide an unstretched fiber capable of producing a stretched fiber excellent in uniformity, a stretched fiber obtained by stretching the same, and a method for producing the same. That is, when drawing, the use of a drawing pin or the undrawn fiber
Unstretched PTT fiber that can obtain a stable drawing condition (drawing yield) and eliminate fineness fluctuations, especially periodic fluctuations, despite being left for a long time exceeding 00 hours, and can be obtained by drawing it. An object of the present invention is to provide a drawn fiber and an industrial production method thereof. The problem to be solved by the present invention is that the PT
An object of the present invention is to minimize the change over time of the T undrawn fiber and to eliminate adverse effects on the drawing condition and the quality of the drawn fiber when left for a long time.

[0013]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by specifying the birefringence and the water content of the unstretched PTT fiber, the stretching condition and the stretching were determined. The inventors have found that the quality of the fiber is significantly improved, and have completed the present invention. That is, the first invention of the present invention
Consisting of 95 mol% or more of trimethylene terephthalate repeating units and 5 mol% or less of other ester repeating units, and composed of polytrimethylene terephthalate having an intrinsic viscosity of 0.7 to 1.3.
An undrawn fiber characterized by satisfying (2). (1) Birefringence of undrawn fiber ≦ 0.06 (2) Water content of undrawn fiber ≦ 2% by weight

A second invention according to the present invention is a drawn fiber obtained by drawing the undrawn fiber according to the first invention, which has a toughness of 20 (cN / dtex)% ^1/2 or more, and an evenness tester. Is 1.5% in continuous fineness fluctuation measurement
A drawn fiber characterized by exhibiting any one of the following characteristics (1), (2) and (3). (1) Periodic fluctuations with an occurrence interval of 10 m or less exist on the Evenness Tester Chart, and the magnitude of the fluctuations is 2% or less relative to the average fineness. (2) On the Evenness Tester chart, the occurrence interval is 10
Although a periodic fluctuation of m or less cannot be determined, a periodic fluctuation of an interval of 10 m or less exists on a periodic analysis diagram of the fineness fluctuation. (3) On the Evenness Tester chart, the occurrence interval is 10
m or less, and no periodic variation with an interval of 10 m or less does not exist on the periodicity analysis diagram of the fineness variation. However, toughness = breaking strength x breaking elongation ^1/2 (cN / d
tex)% ^1/2 measured fiber length of Evenness Tester = 250 m

The third invention of the present invention relates to a polytriethylene resin having a limiting viscosity of 0.7 to 1.3, comprising 95 mol% or more of trimethylene terephthalate repeating units and 5 mol% or less of other ester repeating units. A method for producing an unstretched fiber characterized by satisfying the following requirements (1) to (3) when producing an unstretched fiber comprising methylene terephthalate. (1) After the aqueous emulsion concentration of the finishing agent to be applied to the undrawn fiber is adjusted to 15% by weight or more, and (2) the finishing agent is applied in an applied amount such that the water content of the undrawn fiber is 2% by weight or less. (3) Winding at a winding speed of 3000 m / min or less.

The present invention relates to a PTT fiber comprising 95% by mole or more of trimethylene terephthalate repeating units, 5% by mole or less of other ester repeating units, and having an intrinsic viscosity of 0.7 to 1.3. The present invention is directed to a method of producing a drawn fiber by a two-stage method in which the undrawn fiber is once wound into an undrawn package in a spinning step, and then the undrawn fiber is drawn in a drawing step. In general, drawing in the two-stage method is performed using equipment called a draw twister (draw twister) or a draw winder (draw winder), and the drawn fiber is wound into a shape called a pan in the former and a cheese in the latter. . The drawn fibers are generally twisted in the pan and untwisted in the cheese.

The first invention of the present invention relates to an undrawn fiber which is an intermediate product for producing a drawn fiber by the two-step method. In the unstretched fiber of the present invention, the birefringence of the unstretched fiber wound on the package needs to be 0.06 or less. If the birefringence of the unstretched fiber exceeds 0.06, the fineness of the stretched fiber varies greatly, making it difficult to achieve the object of the present invention. That is, the stress (measured as spinning tension) applied to the fiber by air resistance or the like during the spinning stage
Recovery occurs after the undrawn fiber is wound into a package. However, since shrinkage is regulated at both ends,
As a result, it is presumed that the ears have a form of ear height, and the fineness differs between the ear portion and the other portion, causing periodic fineness fluctuation. The birefringence of the undrawn fiber is preferably 0.05 or less in order to maintain the drawing condition and the quality of the drawn fiber even after being left for a long time. A more preferable birefringence for enhancing the toughness of the drawn fiber is 0.03 or less.

In the unstretched fiber of the present invention, it is important that the moisture content of the unstretched fiber wound around the package is 2% by weight or less. If the moisture content of the undrawn fiber exceeds 2% by weight, the fineness of the drawn fiber is periodically changed and the quality of the drawn fiber is deteriorated, and the drawing condition is also impaired. The reason why the water content of the undrawn fiber has a significant effect on the drawing condition and quality of the drawn fiber is that the water content of the undrawn fiber on the surface and both ends of the undrawn fiber decreases due to long-term storage. The difference from the moisture content of the unstretched fiber in the other portion is increased. It is presumed that this difference in water content becomes a smooth spot or a temperature spot during stretching, and causes periodic fineness fluctuation.

The lower the moisture content of the undrawn fiber wound in the undrawn fiber package, the better. However, if it is 1% by weight or less, the drawing condition and the cycle of the drawn fiber can be maintained even after a long standing time of about 100 hours or more. The generation of the target fineness variation can be almost completely avoided. A more preferable moisture content is 0.8% by weight or less. The undrawn fiber of the present invention is preferably wound around a hard resin or a paper tube. The drawn fiber obtained by drawing from the undrawn fiber of the present invention not only has a good drawing condition but also has excellent drawn fiber quality. The fineness variation value U% of the drawn fiber is 1.5% or less,
In addition, there is substantially no periodic fineness fluctuation derived from low fineness.

The second invention of the present invention is a drawn fiber obtained by drawing the undrawn fiber of the first invention. In the second invention, the toughness must be 20 (cN / dtex)% ^1/2 or more. 20 toughness (cN / dte)
When x) is less than ^1/2 , the knitted fabric obtained by processing the PTT fiber has poor mechanical properties such as tear strength, and is not sufficient as a fiber for clothing. The preferred range of toughness is 22 (cN / dtex)% ^1/2 or more.
Incidentally, the toughness of general polyethylene terephthalate fibers for clothing is about 24 (cN / dtex)% ^1/2 .
In the second invention, U% must be 1.5% or less in a continuous fineness variation measurement using an Evenness tester. If the U% exceeds 1.5%, the uniformity of physical properties and the uniformity of dyeing are poor, and as a result, when processed into a knitted fabric, a dyed pattern and dye streaks are noticeable throughout the knitted fabric and a good one cannot be obtained. . A preferred range of U% is 1.2% or less, and a more preferred range is 1.0% or less. In an undrawn fiber package having a high moisture content of 2% by weight or more, it is considered that the size of the undrawn fiber increases due to drying of the side surface of the package over time, leading to a deterioration in U%. .

In the second invention, there is at least a periodic fineness variation having an occurrence interval of 10 m or less on the chart of continuous fineness measurement by Evennesser, and the magnitude of the variation is 2% or less relative to the average fineness variation. Must. This corresponds to the above (1). What is periodic fluctuation?
It is a fluctuation corresponding to a vertical whisker-like signal existing at equal intervals on the continuous fineness fluctuation measurement chart by the Evenness Tester as shown in FIG. The fact that the signals are observed at equal intervals means that the fineness variation that causes signal generation occurs periodically. The presence of a downward signal means that the fineness (thickness of the fiber) at that point in the fiber length direction fluctuates to the lower side, and the presence of an upward signal indicates that the It means that the fineness of the point fluctuates to the higher side.
As described above, the ratio of the fineness variation to the average fineness ratio can be read directly from the chart. If this exceeds 2%, when processed into a knitted fabric, even if U% is 1.5% or less, strong periodic spots and gloss spots are remarkable in part due to this periodic fluctuation, and good A knitted fabric for clothing cannot be obtained.

The interval at which the periodic fineness fluctuation occurs is substantially equal to the unstretched fiber length for one stroke × actual stretching ratio between the both ends of the unstretched fiber package or the unstretched fiber length for two strokes × actual stretching ratio. Is equivalent. It is considered that the moisture content of the unstretched fibers present at both ends or one end is reduced by drying, and this becomes heat spots or smooth spots at the time of stretching to become stretched spots, resulting in variation in fineness. In the two-stage method, the interval of the periodic fluctuation is determined by the stroke length of the undrawn fiber winder,
Although it is determined by the helix angle and the stretching ratio, it is usually 10 m or less. When the periodic fluctuation becomes smaller, the continuous fluctuation measurement chart shows FIG.
, Signals at equal intervals above and below cannot be determined. However, as shown in FIG. 3, a signal indicating that there is a periodic fluctuation appears.

As described above, the periodic fluctuation signal is not remarkable on the continuous fluctuation measurement chart, but the signal appears on the periodic analysis chart in the characteristic (2). Incidentally, in the periodic analysis, it is not known from the method whether the signal is on the low fineness side or the high fineness side. This range (2) is a preferred range of the present invention. When the periodic fluctuation is further reduced, no signal is observed in both the continuous fluctuation measurement chart and the periodic analysis chart. This example is shown in FIG. 2 and the cycle analysis diagram 4. This state is a state showing the characteristic of the above (3). This is the most preferred range of the present invention.

Hereinafter, the method for producing an undrawn fiber according to the third invention of the present invention will be described in detail. PTT in the present invention
In the polymer, 95 mol% or more is composed of trimethylene terephthalate repeating units, and 5 mol% or less is composed of other ester repeating units. That is, P in the present invention
TT is a PTT homopolymer and copolymerized polytrimethylene terephthalate containing up to 5 mol% of other ester repeat units. Representative examples of the copolymer component include the following. Examples of the acidic component include aromatic dicarboxylic acids such as isophthalic acid and 5-sodium sulfoisophthalic acid, and aliphatic dicarboxylic acids such as adipic acid and itaconic acid. Examples of the glycol component include ethylene glycol, butylene glycol, polyethylene glycol and the like. Also, hydroxycarboxylic acids such as hydroxybenzoic acid are included in the examples. A plurality of these may be copolymerized.

Further, the PTT of the present invention may have a matting agent such as titanium oxide, a heat stabilizer,
Additives such as antioxidants, antistatic agents, ultraviolet absorbers, antibacterial agents, various pigments, and the like may be contained or may be contained as a copolymer. In the present invention, the intrinsic viscosity of PTT is 0.7-1.
A range of 3 is preferred. Particularly preferably, it is 0.8 to 1.1. The method for producing PTT in the present invention may be a known method, a typical example of which is to increase the degree of polymerization by melt polymerization up to a certain intrinsic viscosity, and then to increase the degree of polymerization by solid phase polymerization to the degree of polymerization corresponding to a predetermined intrinsic viscosity It is a two-step method.

FIG. 5 shows a method for producing unstretched PTT fiber and a method for producing a stretched fiber using the same in the present invention.
This will be described in detail with reference to FIGS. First, in FIG.
P dried to a moisture content of 30 ppm or less in dryer 3
The TT pellets are supplied to the extruder 4 set at a temperature of 255 to 265 ° C. and melted. The molten PTT is then passed through a bend 5 to a spin head 6 set at 250-265 ° C.
And measured by a gear pump. After that, it is extruded as a multifilament 9 into a spinning chamber through a spinneret 8 having a plurality of holes mounted on a spin pack 7. The temperature of the extruder and spin head is PTT
The optimum one is selected from the above range according to the intrinsic viscosity and shape of the pellet.

The PTT multifilament extruded into the spinning chamber is cooled to room temperature by the cooling air 10 and is rotated at a predetermined speed while taking over the godet roll 1.
It is thinned by 2, 13 and solidified and wound up as an undrawn fiber package 15 having a predetermined fineness. Before the undrawn fiber comes into contact with the take-off godet roll 12, the finishing agent is applied by the finishing agent applying device 11. After leaving the take-off godet roll 13, the undrawn fiber is wound up by a winder 14 as an undrawn fiber package. A schematic diagram of the undrawn fiber package is shown in FIG.

In the method for producing an undrawn fiber of the present invention,
A water-based emulsion type is used as a finish to be imparted to undrawn fibers. It is necessary that the concentration of the aqueous emulsion of the finish is 15% by weight or more. If the emulsion concentration is less than 15% by weight, an excessive amount of water is applied to the undrawn fibers in order to give the usual amount of the finishing agent of 0.5 to 1.0% by weight of the drawn fibers after drawing. And the object of the present invention is not achieved. That is, in order to reduce the water content of the undrawn fiber to 2% by weight or less, which is the range of the present invention, by using a finish having an emulsion concentration of less than 15% by weight, it is conceivable to use a small amount of the finish. However, in this case, the applied amount of the finish applied to the drawn fiber is, for example, 0.3% by weight or less, and the smoothness of the drawn fiber is impaired. Preferred emulsion concentrations are 20 to 3
5% by weight.

In the method for producing an undrawn fiber of the present invention, it is necessary to provide a finishing agent amount such that the water content of the undrawn fiber is 2% by weight or less. If the moisture content of the undrawn fiber exceeds 2% by weight, the spinning condition and the quality of the drawn fiber become poor due to long standing, and the object of the present invention is not achieved. Adjustment of the moisture content of undrawn fibers
It can be determined by adjusting the finish emulsion concentration and the amount applied.

In the method for producing an undrawn fiber of the present invention, it is necessary to wind at a winding speed of 3000 m / min or less. When the winding speed exceeds 3000 m / min, the birefringence index of the undrawn fiber exceeds 0.06, and the object of the present invention cannot be achieved. Preferred winding speeds are 1000 to 200
0 m / min, more preferably 1200 to 1800 m
/ Min.

The undrawn fibers are then fed to a drawing step,
It is stretched by a stretching machine as shown in FIG. 6 or FIG. The preservation environment of the undrawn fiber before being supplied to the drawing step is preferably to maintain the atmosphere temperature at 10 to 25 ° C. and the relative humidity at 75 to 100%. The undrawn fiber on the drawing machine is preferably kept at this temperature and humidity throughout the drawing. On the drawing machine, first, the undrawn fiber package 15
Is heated on a supply roll 16 set at 45 to 65 ° C., and is stretched to a predetermined fineness using a peripheral speed ratio between the supply roll 16 and the stretching roll 18. After or during drawing, the fiber travels while contacting a hot plate 17 set at 100 to 150 ° C., and receives a tension heat treatment.
The fiber exiting the drawing roll is wound as a drawn fiber pan 19 while being twisted by the spindle.

More preferably, the supply roll temperature is 50 to
The temperature is 60C, more preferably 52-58C. The ratio between the supply roll 16 and the stretching roll 18, that is, the stretching ratio and the hot plate temperature are preferably set so that the stretching tension is about 0.35 cN / dtex. Further, if necessary, a drawing pin may be provided between the supply roll 16 and the hot plate 17 using a drawing and twisting machine as shown in FIG. 7 to perform drawing. In this case, the supply roll temperature is 50 to 60 ° C,
More preferably, the temperature is strictly controlled to be 52 to 58 ° C. In the production method of the present invention, the effect of the present invention is more remarkably exerted in the case of stretching using a combination of the supply roll temperature and the stretching pin.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail with reference to examples and the like, but needless to say, the present invention is not limited to the examples and the like. The method and conditions for measuring physical properties performed in the examples will be described. (1). Intrinsic viscosity [η] is a value obtained based on the definition of the following equation. [Η] = lim (ηr−1) / C C → 0 In the definition formula, ηr is the viscosity at 35 ° C. of a diluted solution of PTT polymer dissolved in 0-chlorophenol having a purity of 98% or more, measured at the same temperature. The value is divided by the viscosity of the above solution, and is defined as the relative viscosity. C is g /
Polymer concentration expressed in 100 ml.

(2). The moisture content of the fiber was determined by the following equation according to JIS-L-1013. Moisture percentage (% by weight) = [(W1−W2) / W2] × 100 where W1: Weight at the time of sampling (g) W2: Weight of the sample at the time of absolute drying (g)

(3). Continuous fineness fluctuation measurement (chart) and fineness fluctuation value U% Continuous fineness fluctuation chart (Diagram)
Mass) is determined and U% is measured at the same time. Measuring machine Evenness Tester (Zerbeger Worcester; Worcester Tester 4) Measurement conditions ・ Yarn speed 100m / min ・ Number of twists 10,000 times / min ・ Measurement fiber length 250m ・ Scale Set according to the fiber fineness variation

(4). Dyeing grade Determined by an expert based on the following criteria. Grade 5: Most excellent (passed) Grade 4: Excellent (passed) Grade 3: Good (marginally passed) Grade 2: poor (failed) Grade 1: very poor (failed)

[0037]

Examples 1 to 5 and Comparative Examples 1 to 3 PTT pellets containing 0.4% by weight of titanium oxide and having an intrinsic viscosity of 0.91 were subjected to 56 dtex using a spinning machine and a drawing machine as shown in FIGS. A production experiment of a / 24 filament PTT fiber was conducted. In this experiment, by changing the concentration and amount of the finishing agent applied to the undrawn fibers, the moisture content of the undrawn fibers was changed, and the fineness variation of the drawn fibers due to the lag time of these undrawn fibers was changed. The effect on the value U% was investigated. In this spinning machine, 16 spinnerets can be installed at the same time.
Collected individually. In the subsequent drawing, drawing was simultaneously started on the 16 undrawn fibers collected at the same time. The winding of the undrawn fiber is set to 6 kg, and upon drawing,
From this undrawn fiber, a method of collecting four 1.5 kg wound drawn fibers every lag time was used. During the winding, storage and drawing of the unstretched fiber, the unstretched fiber was kept in an atmosphere under certain conditions. As the atmosphere conditions, the temperature was 22
° C and the relative humidity were kept at 90%.

The spinning conditions and the drawing conditions in this example and comparative examples are as follows. (Spinning conditions) Pellet drying temperature and ultimate moisture content 110 ° C., 25 ppm Extruder temperature 260 ° C. Spin head temperature 265 ° C. Spinneret hole diameter 0.40 mm Polymer discharge amount 19 g / min Cooling air temperature: 22 ° C., relative humidity: 90 % Speed: 0.5m / sec Take-off speed 1500m / min

(Unstretched fiber) Fineness 131.1 decitex Birefringence 0.024 Volume weight 6.2 kg / 1 bobbin (Stretching condition) Stretching machine supply roll 55 ° C Stretching pin present Hot plate temperature 130 ° C Stretching roll temperature Non-heating (Room temperature) Stretching ratio Set so that the breaking elongation of the stretched fiber is about 45%. Winding speed 800 m / min

(Physical Properties of Stretched Fiber) Fineness 54.2 decitex Breaking strength 3.5 cN / dtex Breaking elongation 45% Toughness 23 (cN / dtex)% ^1/2 Shrinkage of boiling water 13.1% Water content of undrawn fiber Table 1 shows the fineness fluctuation value U% and the dyeing quality of the drawn fiber obtained by standing and drawing this for up to 120 hours. As is clear from Table 1, if the moisture content of the undrawn fiber is within the range of the present invention, the dyeing of the drawn fiber shows good quality despite the long lag.

[0041]

[Table 1]

[0042]

Examples 6 to 10 and Comparative Example 4 In this example, the effect of the birefringence of undrawn fibers on the dyeing quality of drawn fibers was examined. The spinning conditions and the stretching conditions in the present example and the comparative example are as follows. The water content of the undrawn fiber was 0.8% by weight. The unstretched fiber was kept in a constant-condition atmosphere throughout the winding, storage and stretching of the package. As the atmosphere conditions, the temperature was 22
° C and the relative humidity were kept at 90%.

(Spinning conditions) Pellet drying temperature and ultimate moisture content 110 ° C., 25 ppm Extruder temperature 260 ° C. Spin head temperature 265 ° C. Spinneret hole diameter 0.40 mm Polymer discharge amount Set so that drawn fiber fineness becomes 54 decitex Cooling Wind conditions Temperature: 22 ° C, relative humidity: 90% Speed: 0.5 m / sec Finishing agent emulsion concentration 20% by weight Finishing agent application rate 4.0% by weight

(Drawing conditions) Drawing machine supply roll 55 ° C Drawing pin provided Hot plate temperature 130 ° C Drawing roll temperature Non-heating (room temperature) Drawing ratio Set so that the breaking elongation of the drawn fiber becomes about 45% Winding speed 800m / Min

(Physical Properties of Stretched Fiber) Fineness 54.2 decitex Breaking strength 3.5 cN / dtex Breaking elongation 45% Toughness 23 (cN / dtex)% ^1/2 Shrinkage of boiling water 13.1% Finishing agent adhesion 0.8 Table 2 shows the birefringence of the undrawn fiber and the lag time of 12%.
Fineness fluctuation value U% of drawn fiber which was allowed to stand for 0 hour and drawn
And dyeing quality. As is clear from Table 2, if the birefringence of the undrawn fiber is within the range of the present invention, the dyeing of the drawn fiber shows good quality despite the long lag.

[0046]

[Table 2]

[0047]

According to the production method of the present invention, in the two-step method of producing PTT fiber, that is, a method of producing a drawn fiber comprising spinning, undrawn fiber winding, and subsequent drawing, the change with time of the undrawn fiber is reduced. It is possible to minimize irregularities in the drawing condition and fluctuations in the fineness of the drawn fiber caused by the cause, and to obtain a highly uniform P
TT fibers can be obtained with high shrinkage. PT of the present invention
The T undrawn fiber can keep the fineness fluctuation of the drawn fiber obtained by drawing even by a long lag small.
A highly uniform PTT fiber can be obtained.

[Brief description of the drawings]

FIG. 1 is an evenness tester U% chart (Diagram Mass) chart with remarkable periodic fluctuations.

FIG. 2: Evenness tester U% in which periodic fluctuation is not remarkable
It is a chart figure.

FIG. 3 is a periodic analysis diagram (Spect) in which periodic fluctuations exist.
(program mass).

FIG. 4 is a cycle analysis diagram in which there is no periodic variation.

FIG. 5 is a schematic view of a spinning machine.

FIG. 6 is a schematic view of a twisting machine.

FIG. 7 is a schematic diagram of a twisting machine having a drawing pin.

FIG. 8 is a schematic diagram of an undrawn fiber package.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Undrawn fiber 2 Undrawn fiber winding bobbin 3 Polymer chip dryer 4 Extruder 5 Bend 6 Spin head 7 Spin pack 8 Spinneret 9 Filament 10 Cooling air 11 Finishing device 12 and 13 Godet roll 14 Winder 15 Not yet Drawing fiber package 16 Supply roll 17 Hot plate 18 Drawing roll 19 Pan 20 Drawing pin

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Teruhiko Matsuo 6-4100 Asahimachi, Nobeoka-shi, Miyazaki F-term (reference) 4A035 BB33 BB40 BB56 BB60 BB78 BB89 BB90 EE02 EE20 HH10 JJ05 4L036 MA05 MA25 PA01 PA03 PA09 PA18 RA13 UA25

Claims (7)

[Claims] 1. It is composed of at least 95 mol% of trimethylene terephthalate repeating units and at most 5 mol% of other ester repeating units, and has an intrinsic viscosity of 0.7 to 1.3.
An undrawn fiber comprising polytrimethylene terephthalate, and satisfying the following (1) and (2). (1) Birefringence of undrawn fiber ≦ 0.06 (2) Average moisture content of undrawn fiber ≦ 2% by weight 2. The undrawn fiber according to claim 1, wherein the undrawn fiber has a birefringence of 0.05 or less and an average water content of 1% by weight or less. 3. A drawn fiber obtained by drawing the undrawn fiber according to claim 1, having a toughness of 20 (cN / dt).
ex) at% ^1/2 or more, U% at 1.5% or less in continuous fineness variation measurement with an Evenness tester, and exhibit any of the following characteristics (1), (2) and (3) A drawn fiber, characterized in that: (1) There is a periodic fluctuation on the high fineness side and low fineness side with a generation interval of 10 m or less on the evening tester chart, and the magnitude of the fluctuation is 2% or less relative to the average fineness. (2) On the evening tester chart, the occurrence interval is 10
Although the periodic fluctuation on the high fineness side and the low fineness side of m or less cannot be discriminated, there is a periodic fluctuation with an interval of 10 m or less on the periodicity analysis diagram of the fineness fluctuation. (3) The occurrence interval is 10 on the Evenness Tester chart
The periodic fluctuations on the high fineness side and the low fineness side of m or less cannot be determined, and no periodic fluctuations with an interval of 10 m or less exist on the periodicity analysis diagram of the fineness fluctuations. However, toughness = breaking strength x breaking elongation ^1/2 (CN / d
tex)% ^1/2 measured fiber length of Evenness Tester = 250 m 4. A composition comprising 95 mol% or more of trimethylene terephthalate repeating units and 5 mol% or less of other ester repeating units and having an intrinsic viscosity of 0.7 to 1.3.
A method for producing an undrawn fiber comprising polytrimethylene terephthalate, wherein the method satisfies the following requirements (1) to (3). (1) The aqueous emulsion concentration of the finishing agent to be applied to the undrawn fibers is set to 15% by weight or more, and (2) the finishing agent is applied in such an amount that the average moisture content of the undrawn fibers is 2% by weight or less. Thereafter, (3) winding at a winding speed of 3000 m / min or less. 5. The aqueous emulsion concentration of the finishing agent is 20
% By weight or more and an average moisture content of the undrawn fiber is 1% by weight.
The method for producing an undrawn fiber according to claim 4, wherein the winding is carried out in less than one minute. 6. The undrawn yarn according to claim 4, wherein the undrawn yarn is 45 to 65.
A method for producing a drawn fiber, comprising drawing at a temperature of ° C. 7. The undrawn yarn according to claim 4, wherein the undrawn yarn is 50 to 60.
C. and a drawing method using a drawing pin.