CA3236004A1

CA3236004A1 - Polytrimethylene terephthalate fiber and method for producing same

Info

Publication number: CA3236004A1
Application number: CA3236004A
Authority: CA
Inventors: Hiroyuki Yoneda
Original assignee: Teijin Frontier Co Ltd
Current assignee: Teijin Frontier Co Ltd
Priority date: 2021-10-19
Filing date: 2022-10-14
Publication date: 2023-04-27
Also published as: TW202331037A; JPWO2023068178A1; EP4421223A1; WO2023068178A1; JP7277680B1; KR20240070715A

Abstract

A polytrimethylene terephthalate fiber according to the present invention has a peak value of the thermal stress of the fiber within the temperature range from 40°C to 100°C, with the peak value being 0.1 cN/dtex to 0.8 cN/dtex, while having an elongation at break of 60% to 200%. With respect to a method for producing this fiber according to the present invention, a polytrimethylene terephthalate is melted and solidified, and is subsequently wound at a winding speed of 1,000 m/minute or more; then, the polytrimethylene terephthalate is heated by a heating roller at the glass transition temperature ±20°C, and is stretched 1.0 to 2.0 times; and subsequently, after being twisted around a heating roller at 50°C to 150°C, the resulting polytrimethylene terephthalate is wound at a winding speed of 2,000 m/minute to 4,800 m/minute.

Description

DESCRIPTION
Title of Invention: POLYTRIMETHYLENE TEREPHTHALATE FIBER AND
METHOD FOR PRODUCING SAME
Technical Field [0001]
The present invention relates to a polytrimethylene terephthalate fiber having excellent texturing processability and a method for producing the same. More particularly, the present invention is concerned with a polytrimethylene terephthalate fiber having high elongation and high shrinkage stress and having excellent process passing properties upon being textured and a method for producing the same.
Background Art

[0002]
Polytrimethylene terephthalate (hereinafter, frequently referred to simply as "PTT") is a polymer obtained by subjecting terephthalic acid, or a lower alcohol ester of terephthalic acid, such as dimethyl terephthalate, and trimethylene glycol (1,3-propanediol) to polycondensation, and a fiber using the polymer has both properties similar to those of polyamide, such as a low modulus (soft hand feeling), excellent elastic recovery, and dyeability, and performance similar to those of a polyethylene terephthalate (hereinafter, frequently referred to simply as "PET") fiber, such as a light resistance, heat setting properties, dimensional stability, and low water absorption, and the fiber of the polymer having such properties has been applied to BCF
carpet, brush, gut for tennis rackets, and the like.

[0003]
With respect to the polytrimethylene terephthalate fiber (hereinafter, frequently referred to simply as "PTT fiber") formed from the above polymer, as a form of fiber for effectively utilizing the above-mentioned properties of the PTT fiber, various types of textured yarns have been known. Especially, a false twisted textured yarn of a PTT fiber has excellent elastic recovery and softness, as compared to a fiber having a molecular structure like that of the PTT fiber, for example, another polyester fiber, such as a PET fiber, and is expected as an Date Regue/Date Received 2024-04-17 extremely excellent raw yarn for stretch.

[0004]
A conventional PTT fiber has essential advantages, such as high elastic recovery and excellent softness; however, the PTT
fiber has a problem in that when texturing a PTT fiber, particularly a PTT fiber having a small single fiber fineness, the process passing properties are poor.

[0005]
For this reason, there is a disadvantage in that the method for texturing a PTT fiber is restricted and hence, particularly, properties of a textured yarn, such crimp properties cannot be satisfactorily improved.

[0006]
For example, with respect to a PET fiber which is a general-purpose fiber, the method for producing various textured yarns using a partially oriented yarn (hereinafter, frequently referred to simply as "POY") having high production rate has been widely conducted.
Particularly, in the method using a partially oriented yarn, such as draw false-twist texturing (so-called "POY-DTY texturing"), a textured yarn having high productivity and excellent crimp properties can be obtained.

[0007]
Therefore, with respect to a PTT fiber having properties like those of the PET fiber, a number of attempts have been made on the texturing method using a PTT partially oriented fiber (hereinafter, frequently referred to simply as "PTT-POY").

[0008]
For example, PTL 1 has proposed a PTT-POY fiber wound at 3,300 m/minute, having a specific finishing agent applied for improving the process passing properties of the fiber, and having a birefringence of 0.059 and an elongation of 71%. Further, PTL
2 discloses a PTT-POY wound at 3,500 m/minute, having a specific finishing agent applied and having a birefringence of 0.062 and an elongation of 74%.

[0009]
However, the PTT-POY fiber disclosed in the above-mentioned patent documents has a problem in that the yarn largely shrinks on a bobbin having the fiber wound to press the bobbin tight, so that the bobbin deforms, making it impossible to remove Date Regue/Date Received 2024-04-17 the cheese-form package from the spindle of the winder. Even when a bobbin having a high strength is used for preventing such deformation, a phenomenon called bulge such that the side wall of the package on the bobbin becomes swollen is observed, or a phenomenon occurs in which the yarn is firmly tightened in the inner layer of the cheese. Further, there are problems in that when unwinding the yarn from the bobbin, the tension is increased and further the tension variation is increased, and in that fluffing and yarn breaking are highly likely to occur upon texturing using a PTT-POY fiber, or uneven crimp or uneven dyeing is caused.

[0010]
For solving the above-mentioned problems, in PTL 3, studies are made on the method in which, before being wound, the yarn is heated to reduce a strain.
Further, in PTL 4, a partially oriented yarn produced with reduced productivity at a spinning speed of lower than 2,500 m/minute is studied. Conversely, PTL
has proposed a fiber which is wound at a spinning speed as high as 4,500 to 8,000 m/minute, and which has a reduced peak temperature for thermal stress.

[0011]
However, all the above-mentioned PTT fibers have a problem about the process passing properties. Further, it is difficult to finally produce a textured yarn having high crimp properties from a conventional partially oriented yarn (POY) using a PTT
fiber.
Citation List Patent Literature

[0012]
PTL 1: JPH11-229276A
PTL 2: W01999/39041 pamphlet PTL 3: JP2001-254226A
PTL 4: JP2015-7306A
PTL 5: JP2001-348729A
Summary of Invention Technical Problem

[0013]
In view of the above, the present invention has been made, and an object of the invention is to provide a polytrimethylene terephthalate fiber having excellent texturing processability Date Regue/Date Received 2024-04-17 and softness and a method for producing the same.
Solution to Problem

[0014]
The polytrimethylene terephthalate fiber of the present invention is a fiber of polytrimethylene terephthalate, 90 mol%
or more of which is comprised of trimethylene terephthalate repeating units, wherein the polytrimethylene terephthalate fiber satisfies all the following requirements (A) to (C):
(A) that, in the temperature-thermal stress curve of the fiber, a peak value of the thermal stress be present in the temperature range of from 40 to 100 C;
(B) that the peak value of the thermal stress in the requirement (A) be 0.1 to 0.8 cN/dtex; and (C) that the fiber has an elongation at break of 60 to 200%.

[0015]
Further, it is preferred that the polytrimethylene terephthalate fiber has the lowest modulus of 0.1 to 3 cN/dtex at an elongation of 10 to 30% of the fiber, and preferred that the polytrimethylene terephthalate fiber has a birefringence (An) of 0.03 to 0.08 and a specific gravity of 1.319 to 1.340.

[0016]
In addition, the method for producing a polytrimethylene terephthalate fiber of the present invention comprises melting and solidifying polytrimethylene terephthalate, 90 mol% or more of which is comprised of trimethylene terephthalate repeating units, and then winding up the solidified polytrimethylene terephthalate at a winding speed of 1,000 m/minute or more and subsequently, heating the resultant polytrimethylene terephthalate using a heated roller at a temperature of the glass transition point of polytrimethylene terephthalate 20 C, and then drawing the heated polytrimethylene terephthalate at a draw ratio of 1.0 to 2.0 times, and further winding the drawn polytrimethylene terephthalate round a heated roller at 50 to 150 C, and then winding up the resultant polytrimethylene terephthalate at a rate of 2,000 to 4,800 m/minute.

[0017]
Further, the present invention includes a textured yarn which is obtained using the above-mentioned polytrimethylene terephthalate fiber, the textured yarn which is a false twisted Date Regue/Date Received 2024-04-17 textured yarn, and a method for producing the textured yarn.
Advantageous Effects of Invention

[0018]
In the present invention, there are provided a polytrimethylene terephthalate fiber having excellent strength and texturing processability and a method for producing the same.
Brief Description of Drawings

[0019]
[FIG. 1] FIG. 1 is a diagram for explaining the maximum value of the thermal stress in the temperature-thermal stress curve of the fiber.
[FIG. 2] FIG. 2 is a diagram for explaining the method for measuring a maximum crimp stress and a maximum crimp elongation.
[FIG. 3] FIG. 3 is diagrams showing examples of the shape of a yarn having an irregular shaped cross-section and the irregularity.
[FIG. 4] FIG. 4 is diagrams showing examples of the shape of a yarn having a flattened cross-section and the irregularity.
Description of Embodiments

[0020]
Hereinbelow, the present invention will be described in detail.

[0021]
(1) Polymer raw material The polymer used in the invention is described. The polyester polymer constituting the fiber of the invention is polytrimethylene terephthalate (PTT), which is comprised of trimethylene terephthalate repeating units in an amount of 90mo1% or more. The "PTT" is a polyester having terephthalic acid as an acid component and trimethylene glycol (referred to also as "1,3-propanediol") as a diol component. The PTT may further contain a copolymerizable component in an amount of 10 mol% or less.

[0022]
Examples of such copolymerizable components include ester forming monomers, such as sodium 5-sulfoisophthalate, potassium 5-sulfoisophthalate, tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate, tributylmethylphosphonium 3,5-dicarboxybenzenesulfonate, 1,4-butanediol, neopentyl glycol, 1,6-hexamethylene glycol, 1,4-cyclohexanediol, 1,4-Date Regue/Date Received 2024-04-17 cyclohexanedimethanol, adipic acid, dodecanedioic acid, and 1,4-cyclohexanedicarboxylic acid.

[0023]
Further, if necessary, an additive, such as a matting agent, a heat stabilizer, an anti-foaming agent, a toning agent, a flame retardant, an antioxidant, an ultraviolet light absorber, an infrared light absorber, a nucleating agent, or a fluorescent brightener, may be copolymerized with or mixed into the polymer.

[0024]
The polymer used in the invention preferably has an intrinsic viscosity [n] of 0.5 to 1.5, further preferably 0.75 to 1.2. When the intrinsic viscosity of the polymer is in the above range, a fiber having excellent strength and spinning properties can be obtained. When the intrinsic viscosity of the polymer is less than 0.5, the polymer has too low a molecular weight, and hence yarn breaking and fluffing are likely to occur upon spinning or texturing, and further it is difficult to exhibit a strength required for a false twisted textured yarn or the like.
Conversely, when the intrinsic viscosity of the polymer is more than 1.5, the melt viscosity is too high, leading to a disadvantage in that melt fracture or spinning failure occurs upon spinning. The intrinsic viscosity [n] is a measured value described below in the item of the Examples of the invention.

[0025]
With respect to the method for producing the polymer used in the invention, a conventionally known method can be used.
Specifically, terephthalic acid or dimethyl terephthalate and trimethylene glycol are used as raw materials, and one or two or more metal salts, such as a mixture of titanium tetrabutoxide, calcium acetate, magnesium acetate, cobalt acetate, manganese acetate, titanium dioxide or silicon dioxide, are added to the raw materials, and the resultant mixture is subjected to reaction under atmospheric pressure or under a pressure, and then a catalyst, such as titanium tetrabutoxide or antimony acetate, is added and the resultant mixture is subjected to reaction at 250 to 270 C under a reduced pressure. In an arbitrary stage of polymerization, preferably before the polycondensation reaction, a stabilizer is preferably added from the viewpoint of the improvement of the whiteness, improvement of the melt stability, Date Regue/Date Received 2024-04-17 and controlling formation of an organic material having a molecular weight of 300 or less, such as a PTT oligomer, acrolein, or allyl alcohol. The stabilizer used in this case is preferably a pentavalent or/and trivalent phosphorus compound or hindered phenol compound.

[0026]
(2) Polytrimethylene terephthalate fiber The polytrimethylene terephthalate fiber (PTT fiber) of the invention is formed from the above-mentioned polymer, which is comprised of trimethylene terephthalate repeating units in an amount of 90mo1% or more. The PTT fiber can be obtained by melt spinning, drawing, and heating PTT according to, for example, the below-mentioned method.

[0027]
The PTT fiber of the invention needs to satisfy all the following requirements (A) to (C):
(A) that, in the temperature-thermal stress curve of the fiber, a peak value of the thermal stress be present in the temperature range of from 40 to 100 C;
(B) that the peak value of the thermal stress in the requirement (A) be 0.1 to 0.8 cN/dtex; and (C) that the fiber has an elongation at break of 60 to 200%.

[0028]
First, with respect to the PTT fiber of the invention, it is necessary that, in the temperature-thermal stress curve of the fiber, a peak value of the thermal stress, which corresponds to a maximum value (maximum) of the thermal stress (hereinafter, frequently referred to as "thermal shrinkage stress"), be present in the temperature range of from 40 to 100 C. The expression "peak value of the thermal stress" means a value of the maximum (peak) of the thermal stress, which corresponds to a point in a temperature-thermal stress curve of the fiber, drawn as shown in FIG. 1, at which a differential coefficient of the temperature-thermal stress curve changes from positive one to negative one. Further, the expression "maximum value of the thermal stress" means a value of the maximum of the peak values of the thermal stress in the whole temperature range.

[0029]
When the peak value of the thermal stress is present only Date Regue/Date Received 2024-04-17 in the temperature range of lower than 40 C, the fiber largely shrinks after being wound, causing tight winding of the fiber.
On the other hand, when the peak value of the thermal stress is present only in the temperature range of higher than 100 C, the fiber has too high crystallinity, and hence a textured yarn formed from such a fiber cannot obtain soft properties derived from the PTT fiber. Especially when a false twisted textured yarn is produced from the fiber, it is difficult to impart high crimp properties to the yarn. A preferred temperature range in which the peak value of the thermal stress is present is more than 50 to 100 C.

[0030]
Another one or more peaks may be present, for example, in the temperature range of 100 C or more as long as the peak value of the thermal stress is present in the temperature range of from 40 to 100 C as mentioned above. In this case, the peak value or values of the thermal stress present in the temperature range of 100 C or more may be either larger than or smaller than the peak value of the thermal stress present in the temperature range of from 40 to 100 C, but it is preferred that the peak value in the temperature range of from 40 to 100 C is the maximum value of the other peaks.

[0031]
In the PTT fiber of the invention, it is necessary that the peak value of the thermal stress be in the range of from 0.1 to 0.8 cN/dtex. Further, the peak value of the thermal stress is preferably in the range of from 0.11 to 0.6 cN/dtex, further preferably 0.13 to 0.5 cN/dtex, especially preferably 0.15 to 0.4 cN/dtex. When the peak value of the thermal stress is too small, the tension during texturing is reduced, making it difficult to satisfactorily crimp the fiber. On the other hand, when the peak value of the thermal stress is too large, the tension during texturing is considerably increased, causing yarn breaking, or losing softness.

[0032]
Further, it is necessary that the PTT fiber of the invention have an elongation at break of 60 to 200%. When the elongation at break of the PTT fiber is less than 60%, the elongation is such low that fluffing and yarn breaking are likely to occur upon spinning or texturing. On the other hand, when Date Regue/Date Received 2024-04-17 the elongation at break of the PTT fiber is more than 200%, the degree of orientation of the fiber is too low, and hence the fiber is easily changed with time, and, even when stored at room temperature, the fiber is likely to become very brittle. In the case of such a fiber, a textured yarn of industrially consistent quality cannot be stably obtained. A preferred range of the elongation at break is 70 to 180%, a more preferred range is 75 to 150%, and an especially preferred range is 80 to 130%.

[0033]
A most characteristic feature of the PTT fiber of the invention is that a peak of the thermal stress of 0.1 to 0.8 cN/dtex is present in the temperature range of from 40 to 100 C.
By virtue of such a peak of the thermal shrinkage stress present in the above-mentioned temperature range, the PTT fiber of the invention is a fiber having the crystallinity suppressed despite the degree of orientation. Conversely, when the crystallinity of the PTT fiber is too high, it is likely that the peak of the thermal stress on the high temperature side of 100 C or more is increased, and the peak value of the thermal stress is more than 0.8 cN/dtex. Further, when the peak value of the thermal stress is less than 0.1 cN/dtex, the degree of orientation is such small that the subsequent process passing properties become poor, making it impossible to achieve satisfactory texturing.
Especially, the crimp property obtained by false-twist texturing is of an unsatisfactory level from a practical point of view.

[0034]
With respect to the PTT fiber of the invention, the peak temperature for the thermal stress and the stress value are in their respective appropriate ranges, and therefore the fiber has such excellent texturing processability that tight winding of the fiber or yarn breaking in the subsequent texturing does not occur. Further, the fiber exhibits both excellent texturing processability and excellent crimp property, particularly when subjected to draw false-twist texturing.

[0035]
The PTT fiber of the invention preferably has a single fiber fineness of 0.3 to 6.0 dtex, further preferably 0.5 to 3.2 dtex, especially preferably 0.6 to 3.0 dtex. When the single fiber fineness of the PTT fiber is too large, the single yarn has such large size that a cloth obtained from the yarn loses Date Regue/Date Received 2024-04-17 softness. On the other hand, when the single fiber fineness of the PTT fiber is smaller than 0.3 dtex, yarn breaking is highly likely to occur, making it difficult to produce a fiber.

[0036]
Further, when spinning the PTT fiber of the invention, the number of filaments is preferably 3 to 500, further preferably to 300, especially preferably 10 to 200. A yarn formed from the filaments preferably has a total fineness of 10 to 200 dtex, further preferably 20 to 150 dtex. When the total fineness of the yarn is too small, such small total fineness makes it difficult to texture the yarn subsequently. On the other hand, when the total fineness of the yarn is too large, a cloth using the resultant textured yarn disadvantageously loses softness.

[0037]
The PTT fiber of the invention preferably has a shrinkage rate of 1 to 50% in warm water at 65 C. When the 65 C warm water shrinkage rate of the PTT fiber is too high, it is likely that the structure of the fiber is not fixed, and the fiber becomes brittle even when stored at room temperature, making it difficult to stably produce a textured yarn without suffering fluffing or yarn breaking. On the other hand, when the shrinkage rate of the PTT fiber in warm water at 65 C is too low, crystallization has proceeded and therefore, the fiber is brittle or is unlikely to be deformed, so that fluffing and yarn breaking are highly likely to occur, making it difficult to conduct false-twist texturing.

[0038]
The PTT fiber of the invention preferably has a fineness variation value U% of 0 to 2%. The fineness variation value U%
of the PTT fiber is a value determined from variation of the mass of a fiber sample by means of USTER TESTER UT-5, manufactured by Zellweger lister, in a half Inert mode. In the apparatus, variation of the mass can be measured from a change of the permittivity caused when permitting a fiber sample to pass between electrodes. When the fiber is passed through the apparatus at a constant rate, an unevenness curve is obtained, and thus, from the results, a fineness variation value U% (hi%) can be determined. When the fineness variation value U% (hi%) of the PTT fiber is more than 2%, it is likely that fluffing and yarn breaking frequently occur upon false-twist texturing, or Date Regue/Date Received 2024-04-17 only a textured yarn having severe uneven dyeing or uneven crimp can be obtained. The fineness variation value U% (hi%) of the PTT fiber is preferably 1.5% or less, further preferably 1.0% or less. The U% is preferably lower.

[0039]
The PTT fiber of the invention preferably has the lowest modulus in the range of from 0.1 to 3 cN/dtex, further preferably in the range of from 0.1 to 2 cN/dtex, at an elongation of 10 to 30% of the fiber. When the lowest modulus at an elongation of to 30% of the PTT fiber is too small, a disadvantage is caused in that the tension during texturing is reduced, making it difficult to satisfactorily crimp the fiber, or the tension is not stabilized when texturing the yarn, leading to uneven dyeing.
On the other hand, when the lowest modulus of the PTT fiber is too large, a disadvantage is caused in that the tension during texturing is increased, causing yarn breaking, or losing softness.

[0040]
The polytrimethylene terephthalate fiber of the invention preferably has a birefringence (An) of 0.03 to 0.08. When the birefringence (An) of the fiber is too small, it is likely that, for example, the process passing properties of the yarn in the subsequent texturing accompanied by drawing become poor.
Further, there is a tendency that the crimp property obtained after false-twist texturing is unsatisfactory. On the other hand, when the birefringence (An) of the fiber is too large, tight winding of the fiber is likely to occur, so that the process passing properties upon spinning or post-texturing become poor.

[0041]
The polytrimethylene terephthalate fiber of the invention preferably has a specific gravity of 1.319 to 1.340. The specific gravity of the fiber is proportional to the crystallinity. When the specific gravity of the fiber is small, tight winding of the fiber is likely to occur. Particularly, in texturing the fiber while drawing, the texturing is difficult.
On the other hand, when the specific gravity of the fiber is large, fluffing is disadvantageously highly likely to occur.
Further, when the post-texturing is false-twist texturing, there is a tendency that it is difficult to crimp the fiber.

Date Regue/Date Received 2024-04-17

[0042]
From the viewpoint of the process stability, the cross-sectional shape of the PTT fiber of the invention is preferably a solid circular cross-section, but the PTT fiber may be a fiber having an irregular shaped cross-section or a hollow fiber. For example, the PTT fiber of the invention can be composed of a fiber having an irregular shaped cross-section, such as a cruciform cross-section, a triangular cross-section, or a star shaped cross-section, or a fiber having a flattened cross-section, and, by virtue of this, unique hand feeling can be advantageously obtained. When the irregularity or flatness is too large, fluffing is likely to occur upon spinning, so that the stability becomes poor.

[0043]
The above-mentioned PTT fiber of the invention is a fiber such that the temperature range in which a peak value of the thermal stress is present, the peak value (maximum value), and the elongation at break are in their respective appropriate ranges, wherein the fiber has both appropriate orientation of the non-crystalline portion and crystallinity. The above-mentioned PTT fiber of the invention is advantageously used especially in post-texturing including drawing at a high rate.
Particularly, in draw false-twist texturing, tight winding of the fiber yarn can be suppressed before the texturing and after the texturing. Further, by conducting POY-DTY texturing using the PTT fiber, a textured yarn having high crimp property can be obtained, and a false twisted textured yarn having a large modulus (maximum crimp stress) in the process in which crimp of the textured yarn is stretched and excellent stretch back properties is obtained.

[0044]
Further, the PTT fiber of the invention enables stable texturing, despite the fiber having a low single fiber fineness and is very advantageously in production of a cloth having soft hand feeling. In addition, even when being in the state of a partially oriented yarn before subjected to post-texturing, the PTT fiber of the invention maintains stable physical properties for a long term, and thus is particularly useful from an industrial point of view.

[0045]

Date Regue/Date Received 2024-04-17 (3) Method for producing a polytrimethylene terephthalate fiber The above-mentioned polytrimethylene terephthalate fiber (PTT fiber) is obtained by winding up polytrimethylene terephthalate (PTT), which is molten and then solidified, at a winding speed of 1,000 m/minute or more and then heating the resultant polytrimethylene terephthalate using a heated roller at a temperature of the glass transition point of PTT 20 C , and then drawing the heated polytrimethylene terephthalate at a draw ratio of 1.0 to 2.0 times, and winding the drawn polytrimethylene terephthalate round a heated roller at 50 to 150 C and then winding up the resultant polytrimethylene terephthalate at a rate of 2,000 to 4,800 m/minute.

[0046]
With respect to the PTT polymer which is molten and then solidified, the winding speed of the PTT polymer immediately after spun from a spinneret needs to be a speed of 1,000 m/minute or more, and is further preferably a speed of 1,000 to 4,000 m/minute, especially preferably 1,300 to 3,000 m/minute. When the PTT polymer is wound at less than 1,000 m/minute, the orientation of mainly the non-crystalline portion of PTT is small, so that a PTT yarn finally having satisfactory partial orientation cannot be obtained. Further, tight winding of the raw yarn is more severe, and the maximum value of the thermal shrinkage stress becomes a small value. In this case, in the subsequent false-twist texturing or the like, high crimp property cannot be obtained.

[0047]
The temperature at which the wound PTT fiber is treated immediately before subjected to drawing needs to be low temperature heating in the range of the temperature of the glass transition point of PTT 20 C. The temperature is further preferably in the range of from the glass transition point of PTT -20 C to the glass transition point of PTT +10 C, especially preferably in the range of the temperature from the glass transition point of PTT -15 C to the glass transition point of PTT +5 C. When the fiber is at a temperature lower than the glass transition point of PTT -20 C, the fiber being subjected to drawing suffers necking to cause the drawing point to be unstable, leading to severe yarn mottle. Further, necking causes the fiber to generate heat, so that the necking portion tends to Date Regue/Date Received 2024-04-17 be at a temperature higher than the temperature of the glass transition point of PTT +20 C. On the other hand, when the heat treatment is conducted using a heated roller at a temperature higher than the glass transition point of PTT +20 C, the drawing tension is reduced and a pitch of the running yarn is not stabilized, so that a yarn is in contact with another one, causing yarn breaking. Polytrimethylene terephthalate (PTT) has a molecular structure of a zigzag configuration, which is different from that of polyethylene terephthalate (PET) that is a similar polyester fiber, and therefore the glass transition point of PTT is as low as 55 C or less.

[0048]
In the method of the invention, in the heat treatment using a heated roller at a temperature of the glass transition point of PTT 20 C, it is preferred that the fiber is wound round a self-driving metal roll two or more times so that the fiber is stably in the appropriate temperature range.

[0049]
Further, it is preferred that before the above-mentioned treatment using a low temperature heated roller, by applying wind to the polymer, which is molten and solidified, to quickly cool the polymer, or applying an oil agent to the polymer, the temperature of the fiber is reduced once.

[0050]
The circumferential speed of the roller for low temperature heating immediately before the drawing treatment is preferably a speed of 1,000 to 4,000 m/minute, further preferably 1,300 to 3,000 m/minute, especially preferably 1,700 to 2,500 m/minute.

[0051]
In the method for producing a PTT fiber of the invention, it is necessary that, after the treatment using a low-temperature heated roller, drawing at a draw ratio of 1.0 to 2.0 times be conducted. When the draw ratio is smaller than 1.0 time, that is, the polymer is not drawn, the degree of orientation of the non-crystalline portion of the polymer is reduced, causing a problem, for example, in that spinning cannot be performed due to the loosening fiber. On the other hand, when the draw ratio is larger than 2.0 times, the crystallinity is considerably increased, making it difficult to conduct effective post-texturing. For example, draw false-twist texturing cannot Date Regue/Date Received 2024-04-17 impart high crimp properties to the fiber. Further, the draw ratio for the drawing at a low temperature is preferably more than 1.03 to less than 2.0 times, further preferably in the range of from 1.05 to 1.8 times, especially preferably 1.1 to 1.6 times.

[0052]
In the method of the invention, it is important that drawing is conducted at a relatively low temperature near the glass transition point of PTT as mentioned above. In general, high temperature heat drawing, the orientation or crystallinity of the polymer molecules is increased, so that the maximum value of peak of the thermal stress shifts to the high temperature side of 100 C or more. Such a fiber is reduced in elongation at break, making it difficult to conduct effective post-texturing, particularly post-texturing, such as false-twist crimping accompanied by drawing.

[0053]
In the method of the invention, it is necessary that after drawn at a low temperature, the fiber be heated using a heated roller at 50 to 150 C. With respect to the treatment using a heated roller conducted in this instance, it is preferred that the fiber is wound round a self-driving metal roll two or more times. When the temperature of the heated roller is lower than 50 C, the crystallinity is unsatisfactory such that the wound yarn loosens, making impossible to achieve stable winding. On the other hand, when the fiber is wound round a heated roller at a temperature of higher than 150 C, the crystallinity becomes too high, and the tension during yarn texturing is increased, so that the draw ratio in post-texturing cannot be increased. For example, draw false-twist texturing cannot impart satisfactory crimp to the fiber.

[0054]
In the method for producing a PTT fiber of the invention, the above-mentioned drawing at a relatively low temperature near the glass transition point of PTT is performed and subsequently thermosetting is conducted, and therefore the storage stability and post-texturing are improved. Further, the obtained PTT fiber is a PTT partially oriented fiber having properties similar to those of a conventionally known PET-POY and having excellent process passing properties.
Date Regue/Date Received 2024-04-17

[0055]
Further, after being wound round the heated roller, the final winding speed for the PTT fiber which is molten and then solidified needs to be in the range of from 2,000 to 4,800 m/minute. The final winding speed is further preferably in the range of from 2,200 to 4,000 m/minute, especially preferably 2,400 to 3,500 m/minute. When the final winding speed is smaller than 2,000 m/minute, the orientation of the fiber is low and therefore, particularly, when the fiber is stored at a high temperature and at a high humidity, the fiber becomes brittle, making difficult handling of the fiber or draw false-twist texturing. On the other hand, when the winding speed for the PTT fiber which is molten and then solidified is more than 4,800 m/minute, crystallization has proceeded and therefore, elongation of the fiber becomes too low, so that the fiber is not suitable for the subsequent various post-texturing. Further, fluffing and yarn breaking are likely to occur upon spinning or false-twist texturing.

[0056]
The tension for winding the fiber is preferably 0.02 to 0.20 cN/dtex. In the melt spinning of PET, nylon, or the like, which has conventionally been conducted, when the fiber is wound with such a low tension, running of the yarn is not stabilized and the yarn is removed from a traverse of the winder, so that yarn breaking occurs, or a mistake of changing is caused when automatically changing the yarn to be wound to the next bobbin by an autowinder or the like.

[0057]
The PTT fiber, however, does not cause such a problem even when wound with an extremely low tension, and rather, when the PTT fiber is wound with a low tension, tight winding of the fiber does not occur and a cheese-form package having more excellent shape of winding can be obtained. When the tension is too low, it is likely that traverse by a traverse guide of the winder is difficult, so that bulge or the like occurs, causing a poor package, or that the yarn is removed from a traverse, causing yarn breaking. Conversely, when the tension is too high, it is likely that tight winding of the fiber becomes more marked with the passage of time. The tension for winding the fiber is further preferably 0.025 to 0.15 cN/dtex, especially preferably Date Regue/Date Received 2024-04-17 0.03 to 0.10 cN/dtex.

[0058]
In the invention, in the spinning process, if necessary, an interlacing treatment (interlace) may be performed. The interlacing treatment may be conducted before applying a finishing agent, before the heat treatment, or before winding, or may be conducted in two or more sites.

[0059]
The winder used in the invention may be a winder of any of a spindle driving system, a touch roll driving system, and a system which is driving both a spindle and a touch roll, but the winder of a system which is driving both a spindle and a touch roll is preferred for winding the yarn in a large amount. In the case where only one of the touch roll and the spindle is driven, another one is rotated due to friction caused by a driving shaft, and therefore sliding causes a difference in the surface speed between the bobbin fitted to the spindle and the touch roll. For this reason, when the yarn is wound round the spindle from the touch roll, the yarn is likely to be stretched or loosened to change the tension, so that the shape of winding becomes poor or the yarn suffers a damage due to abrasion. When driving both the spindle and the touch roll, a difference in the surface speed between the touch roll and the bobbin can be controlled to reduce sliding, achieving excellent yarn quality or excellent shape of winding.

[0060]
When winding the fiber, the lead angle is preferably 3.5 to 11 . When the lead angle is less than 3.5 , the yarns unlikely cross each other and hence easily slide, so that cob-webbing and bulge are likely to occur. On the other hand, when the lead angle is more than 11 , the amount of the yarn wound round the end portion of the bobbin is increased, so that the diameter of the end portion is large, as compared to that of the middle portion. For this reason, when winding the yarn, only the end portion is in contact with the touch roll, causing the yarn quality to be poor, and further the tension variation is increased when unwinding the wound yarn, so that fluffing and yarn breaking are highly likely to occur. The lead angle is further preferably 4 to 10 , especially preferably 5 to 9 . Thus, a cheese-form package composed of the specific polyester fiber Date Regue/Date Received 2024-04-17 of the invention can be obtained.

[0061]
The PTT fiber obtained by the above-mentioned method of the invention is a so-called partially oriented fiber (POY), which is a fiber such that polymer molecules constituting the fiber are oriented to an appropriate extent. In a method for producing a POY of a general polyester fiber, only high rate spinning in which the take-up rate (spinning speed) after melt-extrusion is 2,500 m/minute or more is performed, and generally, such a drawing treatment that the elongation is lowered is not conducted. In contrast, the requirements of the invention include drawing at a relatively low temperature near the glass transition point of PTT and a heat treatment at a high temperature for improving the storage stability and texturing processability of PTT. In the method of the invention, drawing at a low temperature is conducted and subsequently the heat treatment is immediately performed, and thus an effect is obtained such that the storage stability of the PTT fiber is improved.

[0062]
(4) Textured yarn comprising a polytrimethylene terephthalate fiber The textured yarn of the present invention is a textured yarn which is obtained using the above-described polytrimethylene terephthalate fiber (PTT fiber). Further, the textured yarn of the invention is preferably a false twisted textured yarn.

[0063]
The false twisted textured yarn which is a preferred embodiment of the present invention preferably satisfies the physical properties mentioned below.

[0064]
Specifically, it is preferred that the polytrimethylene terephthalate false twisted textured yarn (hereinafter, frequently referred to as "PTT false twisted textured yarn") is formed from polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90 mol% or more, and satisfies all the following requirements (1) to (6):

[0065]

Date Regue/Date Received 2024-04-17 (1) single fiber fineness: 3.2 dtex or less;
(2) breaking strength 2.5 cN/dtex;
(3) elongation at break: 20 to 80%;
(4) maximum crimp elongation 150%; and (5) maximum crimp stress 0.020 cN/dtex.

[0066]
The PTT false twisted textured yarn in the invention preferably has a single fiber fineness of 3.2 dtex or less.
Further, the single fiber fineness of the yarn is preferably 0.1 dtex or more, or 0.3 to 3.2 dtex, more preferably 0.5 to 3.0 dtex, further preferably 0.6 to 2.4 dtex. When the single fiber fineness of the yarn is larger than 3.2 dtex, the single yarn having such a large size loses cloth softness. On the other hand, when the single fiber fineness of the yarn is too small, yarn breaking is highly likely to occur, making it difficult to produce a fiber.

[0067]
The PTT false twisted textured yarn in the invention preferably has a breaking strength of 2.5 cN/dtex or more, more preferably in the range of from 2.5 to 4.0 cN/dtex, especially preferably in the range of from 2.7 to 3.7 cN/dtex. When the breaking strength of the yarn is smaller than 2.5 cN/dtex, practical use of the yarn is difficult.

[0068]
The PTT false twisted textured yarn in the invention preferably has an elongation at break of 20 to 80%, further preferably in the range of from 22 to 70%, especially preferably 26 to 60%. When the elongation at break of the yarn is less than 20%, the elongation is such low that fluffing and yarn breaking are likely to occur upon spinning or false-twist texturing. On the other hand, when the elongation at break of the yarn is more than 80%, it is likely that plastic deformation of the fiber is so marked that the form stability becomes poor.

[0069]
The PTT false twisted textured yarn in the invention preferably has a maximum crimp elongation of 150% or more. When the maximum crimp elongation of the yarn is less than 150%, it is likely that the crimp elongation is such low that satisfactory stretchability cannot be obtained.

[0070]

Date Regue/Date Received 2024-04-17 The PTT false twisted textured yarn in the invention preferably has a maximum crimp stress of 0.020 cN/dtex or more.
When the maximum crimp stress of the yarn is less than 0.020 cN/dtex, it is likely that the crimp stress is reduced so that the stretch back properties become poor.

[0071]
Conventionally, there has not been obtained a PTT fiber textured yarn of stable quality having excellent crimp properties and a large elongation at break, wherein the yarn is formed from such a thin PTT fiber having excellent hand feeling and touch feeling. In the invention, with respect to the PTT
fiber such that the temperature range in which a maximum value of the thermal stress is present, the maximum value, and the elongation at break are in their respective appropriate ranges, by using the PTT fiber in post-texturing, a post-textured yarn having such excellent physical properties can be obtained. A
polyester textured yarn having excellent stretchability even under a low load, which is the feature of the PTT fiber, can be obtained.

[0072]
Further, the PTT false twisted textured yarn in the invention preferably has a fineness variation value U% (normal %) of 2.0% or less. When the fineness variation value U% (normal %) of the yarn is more than 2.0%, it is likely that fluffing and yarn breaking frequently occur especially upon false-twist texturing, so that a false twisted textured yarn having severe uneven dyeing or uneven crimp is obtained. The U% (normal %) is preferably 1.5% or less. The U% is preferably lower.

[0073]
The fineness variation value U% (normal %) of the false twisted textured yarn is a value determined from variation of the mass of a fiber sample by means of USTER TESTER UT-5, manufactured by Zellweger lister. In the apparatus, variation of the mass can be measured from a change of the permittivity caused when permitting a fiber sample to pass between electrodes. When the fiber is passed through the apparatus at a constant rate, an unevenness curve is obtained. From the results, a fineness variation value U% (normal %) can be determined.

[0074]
Further, the PTT false twisted textured yarn in the Date Regue/Date Received 2024-04-17 invention preferably has a total fineness of 10 to 200 dtex, further preferably in the range of from 15 to 150 dtex, especially preferably 20 to 60 dtex. When the total fineness of the yarn is smaller than 10 dtex, such small total fineness makes it difficult to produce a textured yarn. On the other hand, when the total fineness of the yarn is larger than 200 dtex, a cloth obtained from the yarn disadvantageously loses softness.

[0075]
Further, the PTT false twisted textured yarn in the invention can be composed of a fiber having an irregular shaped cross-section, such as a cruciform cross-section, a triangular cross-section, or a star shaped cross-section, and, by virtue of this, unique hand feeling can be advantageously obtained. The irregularity of the fiber having an irregular shaped cross-section is a value determined by measuring a maximum inscribed circle radius r and a minimum circumcircle radius R of the cross-section of the fiber as shown in FIG. 3, and calculating an irregularity = R/r, and, in the invention, the value of irregularity = R/r is preferably 1.15 to 10.0, further preferably 1.2 to 10Ø When the irregularity of the cross-section is less than 1.15, a difference between the irregular shaped cross-section and a circular cross-section is disadvantageously small.
On the other hand, when the irregularity of the cross-section is more than 10.0, it is likely that a difference in the orientation between the outside and inside of the yarn cross-sectional shape or the like is increased upon spinning, so that the obtained yarn has suffered such severe fluffing and loosening that it is unsuitable for texturing.

[0076]
The PTT false twisted textured yarn in the invention can be composed of a fiber having a flattened cross-section, and, by virtue of this, unique hand feeling can be advantageously obtained. The flatness of the fiber having a flattened cross-section is a value determined by drawing a rectangle circumscribing the cross-section of the fiber as shown in FIG.4, and measuring a long side L and a short side H of the rectangle, and calculating a flatness = L/H, and, in the invention, the value of flatness = L/H is preferably 2.0 to 10Ø When the flatness of the flattened cross-section is less than 2.0, a difference between the flattened cross-section and a circular Date Regue/Date Received 2024-04-17 cross-section is disadvantageously small. On the other hand, when the flatness of the cross-section is more than 10.0, fluffing is likely to occur upon spinning, so that the stability becomes poor.

[0077]
(5) Method for producing a textured yarn comprising a polytrimethylene terephthalate fiber The above-described PTT textured yarn of the invention can be produced by subjecting the above-mentioned polytrimethylene terephthalate fiber (PTT fiber) of the invention to texturing.
Further, the textured yarn of the invention is preferably a false twisted textured yarn produced by subjecting the PTT fiber of the invention to false-twist texturing.

[0078]
Specifically, the PTT textured yarn of the invention can be obtained by subjecting to post-texturing a PTT fiber, which is formed from polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90 mol% or more, and which satisfies all the following requirements (A) to (C):
(A) that, in the temperature-thermal stress curve of the fiber, a maximum value of the thermal stress be present in the temperature range of from 40 to 100 C;
(B) that the maximum value of the thermal stress in the requirement (A) be 0.1 to 0.8 cN/dtex; and (C) that the fiber has a lowest modulus of 0.1 to 2 cN/dtex at an elongation of 10 to 30% of the fiber.

[0079]
The requirements (A) to (C) are like the above-described requirements of the PTT fiber of the invention.

[0080]
Further, in the method for producing a PTT textured yarn of the invention, it is preferred that the PTT textured yarn has the above-mentioned physical properties of the PTT textured yarn.

[0081]
In the invention, by false-twist texturing the above-mentioned PTT fiber, for example, under the conditions shown below, an intended PTT false twisted textured yarn can be obtained.
= Conditions for false-twisting Date Regue/Date Received 2024-04-17 Type of false twister: HTS-15V, manufactured by TMT
Machinery, Inc. (disc false-twisting system) Number of revolutions of disc: 1,000 to 20,000 rpm (disc diameter: 3 to 10 cm) Feed speed: 500 to 1,000 m/minute First feed ratio: -5.0 to +5.0%
First heater temperature (non-contact type): 200 to 300 C
Second heater temperature (non-contact type): 150 to 250 C
Second feed nip roller speed: 600 to 1,500 m/minute Second feed ratio: -5.0 to +5.0%
Feed ratio before wound: -5.0 to +5.0%
In addition to the above-mentioned draw false-twist texturing machine of a disc type, a false-twist texturing machine of a friction type, such as a belt nip type, is suitable for draw false-twist texturing at a high rate with high productivity, which effectively utilizes the characteristic features of the PTT fiber of the invention. Besides, a false-twist texturing machine of a conventional type, such as a pin type or an air twisting type, can be used.

[0082]
The above-described PTT fiber of the invention is a fiber such that the temperature range in which a peak value of the thermal stress is present, the peak value, and the elongation at break are in their respective appropriate ranges, wherein the fiber has both appropriate orientation and crystallinity.
Therefore, the method for producing a textured yarn using the PTT fiber is advantageous in that an occurrence of fluffing and the like are well suppressed even when using the PTT fiber, achieving excellent process passing properties in the subsequent step. The method for producing a textured yarn using the PTT
fiber is suitable particularly for a method including drawing at a high speed, for example, a method using draw false-twist texturing. Further, a PTT textured yarn having such a small single fiber fineness that process passing properties are generally difficult to obtain can be obtained by the method.

[0083]
In the method for producing a PTT textured yarn of the invention, a satisfactory thermal stress is caused in the texturing step, enabling stable texturing.
Therefore, the Date Regue/Date Received 2024-04-17 modulus in the process in which crimp of the PTT textured yarn is stretched is increased, so that a PTT false twisted textured yarn having a large maximum crimp stress and excellent stretch back properties can be obtained.

[0084]
The present invention includes the following inventions.

[0085]
1. A fiber of polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90 mol% or more, the polytrimethylene terephthalate fiber satisfying all the following requirements (A) to (C):
(A) that, in the temperature-thermal stress curve of the fiber, a peak value of the thermal stress be present in the temperature range of from 40 to 100 C;
(B) that the peak value of the thermal stress in the requirement (A) be 0.1 to 0.8 cN/dtex; and (C) that the fiber has an elongation at break of 60 to 200%.

[0086]
2. The polytrimethylene terephthalate fiber according to item 1 above, which has the lowest modulus of 0.1 to 3 cN/dtex at an elongation of 10 to 30% of the fiber.

[0087]
3. The polytrimethylene terephthalate fiber according to item 1 or 2 above, which has a birefringence (An) of 0.03 to 0.08 and a specific gravity of 1.319 to 1.340.

[0088]
4. A method for producing a polytrimethylene terephthalate fiber, comprising melting and solidifying polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90 mol% or more, and then winding up the solidified polytrimethylene terephthalate at a winding speed of 1,000 m/minute or more and subsequently, heating the resultant polytrimethylene terephthalate using a heated roller at a temperature of the glass transition point of polytrimethylene terephthalate 20 C, and then drawing the heated polytrimethylene terephthalate at a draw ratio of 1.0 to 2.0 times, and further winding the drawn polytrimethylene terephthalate round a heated roller at 50 to 150 C, and then winding up the resultant polytrimethylene terephthalate at a Date Regue/Date Received 2024-04-17 speed of 2,000 to 4,800 m/minute.

[0089]
5. A textured yarn which is obtained using the polytrimethylene terephthalate fiber according to any one of items 1 to 3 above.

[0090]
6. The textured yarn according to item 5 above, which is a false twisted textured yarn.

[0091]
7. A method for producing the textured yarn according to item 5 above.

[0092]
8. A polytrimethylene terephthalate false twisted textured yarn which is formed from polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90 mol% or more, the polytrimethylene terephthalate false twisted textured yarn satisfying all the following requirements (1) to (6):
(1) single fiber fineness: 3.2 dtex or less;
(2) breaking strength 2.5 cN/dtex;
(3) elongation at break: 20 to 80%;
(4) maximum crimp elongation 150%; and (5) maximum crimp stress 0.020 cN/dtex.

[0093]
9. The polytrimethylene terephthalate false twisted textured yarn according to item 8 above, which has a total fineness of 10 to 200 dtex.

[0094]
10. The polytrimethylene terephthalate false twisted textured yarn according to item 8 or 9 above, which comprises a fiber having an irregular shaped cross-section, wherein the fiber having an irregular shaped cross-section has an irregularity of 1.15 to 10Ø

[0095]
11. The polytrimethylene terephthalate false twisted textured yarn according to any one of items 8 to 10 above, which comprises a fiber having a flattened cross-section, wherein the fiber having a flattened cross-section has a flatness of 2.0 to 10Ø

[0096]
Date Regue/Date Received 2024-04-17 12. A method for producing a textured yarn, the method comprising texturing the polytrimethylene terephthalate fiber according to any one of items 1 to 3 above.

[0097]
13. A method for producing a false twisted textured yarn, the method comprising false-twist texturing the polytrimethylene terephthalate fiber according to any one of items 1 to 3 above.
Examples

[0098]
Hereinbelow, the present invention will be described in more detail with reference to the following Examples and Comparative Examples, which should not be construed as limiting the scope of the invention. In the following Examples, measurement for the individual items was conducted by the methods described below.

[0099]
(1) Intrinsic viscosity [n]
An intrinsic viscosity [n] was determined using an Ostwald viscometer by extrapolating the ratio risp/C of the specific viscosity nsp in o-chlorophenol at 35 C to the concentration C
(g/100 ml) to a concentration of zero according to the following formula (1).

[0100]
[11] = limc->o(nsp/C) (1) (2) Specific gravity A specific gravity of a sample was measured in accordance with the sink-float method of JIS-L-1013 8.17.1.

[0101]
(3) Birefringence (An) A birefringence was determined in accordance with Sen-i Binran-Genryou Hen (Fiber Handbook-Raw Material Edition), p. 969 (the fifth edition, published by Maruzen Co., Ltd. in 1978), using an optical microscope and a compensator, from retardation of the polarized light observed on the surface of a fiber.

[0102]
(4) Temperature in which a maximum value of the thermal stress is present and maximum value of the thermal stress KE-2, manufactured by Kanebo Engineering Co., Ltd., was used. Measurement was conducted under an initial load of 0.044 Date Regue/Date Received 2024-04-17 cN/dtex at a temperature increase rate of 100 C/minute. With respect to the obtained data, a temperature was plotted on the abscissa and a thermal stress (thermal shrinkage stress) was plotted on the ordinate to draw a temperature-thermal stress curve. A temperature and a thermal stress (thermal shrinkage stress) of the point at which a differential coefficient of the temperature-thermal stress curve changes from positive one to negative one were determined, and the stress was divided by the fineness to determine a maximum stress.

[0103]
(5) 65 C hot water shrinkage rate (HWS) In accordance with JIS-L-1013, using hot water at a temperature of 65 C, a hank dimensional change ratio was obtained and determined as a shrinkage rate in hot water at 65 C.

[0104]
Using a sizing reel having a frame circumference of 1.125 m, an initial load of 0.27 cN/dtex was applied and winding was made at a speed of 120 winding/minute to form a small hank such that the number of winding was 40, and a load 20 times the initial load was applied to the hank and a hank length Lo (mm) was measured. Then, the load was removed, and the sample was immersed in hot water at 65 C for 30 minutes and then removed, and subjected to air-drying and further a load 20 times the initial load was applied to the hank and a hank length L1 (mm) was measured, and a hot water shrinkage rate was calculated from the following formula.
HWS (%) = (Lo - 1,1)/L0 x 100

[0105]
(6) Fineness A fineness of a multifilament yarn was measured in accordance with JIS-L-1013. Further, a single fiber fineness was determined by dividing the obtained value by the number of single filament of the multifilament yarn.

[0106]
(7-1) Fineness variation value U% (PTT fiber; hi%) Using USTER TESTER UT-5, manufactured by Zellweger lister, measurement was conducted in a half Inert mode under the conditions shown below.
Yarn feed speed: 400 m/minute Length of yarn measured: 2,000 m Date Regue/Date Received 2024-04-17

[0107]
(7-2) Fineness variation value U% (textured yarn; normal %) Using USTER TESTER UT-5, manufactured by Zellweger lister, measurement was conducted by the method shown below.
Conditions for measurement Mode: Normal mode Speed of yarn: 200 m/minute Number of twists: 10,000/minute S twisting Tension range: 10 Length of fiber measured: 2,000 m Yarn feed speed: 400 m/minute Length of yarn measured: 2,000 m

[0108]
(8) Breaking strength and elongation at break (fiber breaking strength and fiber elongation at break) In accordance with JIS-L-1013, using Tensilon, manufactured by Orientec Co., Ltd., which is a tensile tester of a type of constant speed of extension, measurement was conducted with a length of specimen between grips of 20 cm and at a speed of pulling of 20 cm/minute.

[0109]
(9) Lowest modulus at an elongation of 10 to 30% of the fiber In accordance with JIS-L-1013, using Tensilon, manufactured by Orientec Co., Ltd., which is a tensile tester of a type of constant speed of extension, measurement was conducted with a length of specimen between grips of 20 cm and at a speed of pulling of 20 cm/minute. With respect to the tangent line of the SS curve at an elongation of 10 to 30%, the slope of a tangent line having the smallest slope was determined as a modulus.

[0110]
(10) Glass transition point A glass transition point was determined by sealing a specified amount of polymer chips in an aluminum sample pan, and increasing the temperature from room temperature to 300 C at a temperature increase rate of 10 C /minute in a nitrogen gas atmosphere by differential scanning calorimeter measurement (DSC) to obtain a temperature increase curve, and measuring a glass transition point from the curve.

[0111]

Date Regue/Date Received 2024-04-17 (11) Crimp property A sample of a polyester false twisted textured yarn was wound round a hank frame under a tension of 0.044 cN/dtex to form a hank having a size of about 3,300 dtex. Two loads of 0.00177 cN/dtex and 0.177 cN/dtex were applied to one end of the hank, and, after the passage of one minute, a length So (cm) was measured.

[0112]
Then, the load of 0.177 cN/dtex was removed from the hank and the hank in this state was treated in boiling water at 100 C
for 20 minutes. After the treatment in boiling water, the load of 0.00177 cN/dtex was removed from the hank, and the hank in a free state without a load was subjected to air-drying for 24 hours, and loads of 0.00177 cN/dtex and 0.177 cN/dtex were further applied to the hank, and, after the passage of one minute, a length S1 (cm) was measured.

[0113]
Then, the load of 0.177 cN/dtex was removed from the hank, and, after the passage of one minute, a length S2 was measured, and a crimp degree was calculated from the following formula, and an average of ten measured values was determined.
Crimp degree (%) = [(S1 - S2)/S0] x 100 A sample such that the crimp degree was 30% or more was considered to have high crimp property, and was rated A, and a sample such that the crimp degree was less than 30% was not considered to have high crimp property, and was rated B.

[0114]
(12) Maximum crimp stress and maximum crimp elongation of a false twisted textured yarn A stress-elongation curve of a false twisted textured yarn is measured by the method described below under the conditions shown below.
a. A false twisted textured yarn is treated in boiling water for 30 minutes and then removed from the water, and allowed to stand and dried in air at room temperature for 4 hours or longer. Then, in accordance with JIS-L-1013 (tensile test method), a stress-elongation curve in which the full stress is up to 0.882 cN/dtex is drawn.
b. On the stress-elongation curve obtained by the measurement by the above-mentioned method under the conditions Date Regue/Date Received 2024-04-17 shown above, as shown in FIG. 1, a point of intersection of the tangent line of the curve for the process (initial) in which crimp is stretched and the tangent line of the curve for the process in which the fiber per se is stretched is determined. A
value obtained by dividing a stress corresponding to the point of intersection by the fineness of the textured yarn is determined as a maximum crimp stress. Further, an elongation corresponding to the point of intersection is determined as a maximum crimp elongation.

[0115]
[Example 1]
Dimethyl terephthalate and 1,3-propanediol in a 1:2 molar ratio were charged, and titanium tetrabutoxide in an amount corresponding to 0.1% by weight of the dimethyl terephthalate was added and a transesterification reaction of the resultant mixture was completed under atmospheric pressure at a heater temperature of 240 C. Then, titanium tetrabutoxide in an amount corresponding to 0.1% by weight of the theoretical polymer amount and titanium dioxide in an amount corresponding to 0.5% by weight of the theoretical polymer amount were further added, and the resultant mixture was subjected to reaction at 270 C for 3 hours.
The obtained polymer was comprised of trimethylene terephthalate repeating units (100 mol%), and had an intrinsic viscosity of 1Ø

[0116]
Further, the obtained polymer had a glass transition point of 51 C.

[0117]
The obtained polymer was dried by a general method so that the water content became 50 ppm, and then molten at 265 C, and extruded through a spinneret having 36 holes each having a diameter of 0.27 mm formed in a single line at a throughput rate of 25.9 g/minute.

[0118]
The extruded molten multifilament was quickly cooled by applying thereto wind at a wind speed of 4.0 m/minute and changed to a solid multifilament, and then, using a guide nozzle, an oil agent containing 60% by weight of octyl stearate, 15% by weight of polyoxyethylene alkyl ether, and 3% by weight of potassium phosphate in the form of a water emulsion finishing agent having Date Regue/Date Received 2024-04-17 a concentration of 10% by weight was applied to the solid multifilament so that the amount of the oil agent applied became 0.6% by weight, based on the weight of the fiber.

[0119]
Then, the solid multifilament was wound round a roll heated to 55 C at a circumferential speed of 2,100 m/minute, and then wound round a roll heated to 80 C so as to be drawn at a draw ratio of 1.3 times, and then, using a winder of a system that drives both a spindle and a touch roll, the resultant multifilament was wound up at a winding speed of 2,600 m/minute, obtaining a cheese-form package having wound 100 dtex/36 filaments (f). Physical properties of the obtained fiber are shown in Table 1. A thermal stress of the obtained fiber was measured, and the results of the measurement showed that the temperature of the first peak of the thermal stress was 61 C and the first peak of the thermal stress was a value as large as 0.20 cN/dtex, but the temperature of the second peak of the thermal stress was 191 C and the second peak of the thermal stress was a value as small as 0.08 cN/dtex or less.

[0120]
Further, false-twist texturing was performed using the above-obtained fiber, and draw false-twist texturing for drawing at a draw ratio of 1.3 times was conducted under the conditions shown below so that the obtained textured yarn had an elongation of 40%. Crimp properties of the obtained false twisted textured yarn are shown in Table 1.
= Conditions for false-twisting Type of false twister: HTS-15V, manufactured by TMT
Machinery, Inc. (disc false-twisting system) Number of revolutions of disc: 5,900 rpm (disc diameter:
5.8 cm) Feed rate: 462 m/minute First feed ratio: 0%
First heater temperature (non-contact type): 280 C
Second heater temperature (non-contact type): 180 C
Second feed nip roller rate: 600 m/minute Second feed ratio: 1.0%
Feed ratio before wound: 3.0%.

[0121]
[Example 2]

Date Regue/Date Received 2024-04-17 Substantially the same procedure as in Example 1 was conducted except that the throughput rate for the polymer, the heat treatment after applying an oil agent, and the draw ratio were changed, obtaining a cheese-form package having wound 100 dtex/36 filaments (f).

[0122]
Specifically, the solid multifilament was wound round the roll heated to 55 C at a circumferential speed which was increased from 2,100 m/minute to 2,300 m/minute, and at a draw ratio which was changed from 1.3 times to 1.2 times, and then wound round a roll heated to 100 C, instead of the heated roller at 80 C. Then, using a winder of a system that drives both a spindle and a touch roll, the resultant multifilament was wound up at a winding speed of 2,650 m/minute. The polymer throughput rate was controlled to adjust the final fineness.

[0123]
Physical properties of the obtained fiber are shown in Table 1. A thermal stress of the obtained fiber was measured, and the results of the measurement showed that the temperature of the first peak of the thermal stress was 61 C and the first peak of the thermal stress was a value as large as 0.17 cN/dtex, but the temperature of the second peak of the thermal stress was 191 C and the second peak of the thermal stress was a value as small as 0.08 cN/dtex or less.

[0124]
Further, false-twist texturing was performed using the above-obtained fiber, and draw false-twist texturing for drawing at a draw ratio of 1.3 times was conducted under the same conditions as those in Example 1 so that the obtained textured yarn had an elongation of 40%. Crimp properties of the obtained false twisted textured yarn are shown in Table 1.

[0125]
[Example 3]
Substantially the same procedure as in Example 1 was conducted except that the throughput rate for the polymer, the heat treatment after applying an oil agent, and the draw ratio were changed, obtaining a cheese-form package having wound 100 dtex/36 filaments (f).

[0126]
Specifically, the solid multifilament was wound round the Date Regue/Date Received 2024-04-17 roll heated to 55 C at a circumferential speed which was increased from 2,100 m/minute to 2,500 m/minute, and at a draw ratio which was changed from 1.3 times to 1.1 times, and then wound round a roll heated to 100 C, instead of the heated roller at 80 C. Then, using a winder of a system that drives both a spindle and a touch roll, the resultant multifilament was wound up at a winding speed of 2,700 m/minute. The polymer throughput rate was controlled to adjust the final fineness.

[0127]
Physical properties of the obtained fiber are shown in Table 1. A thermal stress of the obtained fiber was measured, and the results of the measurement showed that the temperature of the first peak of the thermal stress was 60 C and the first peak of the thermal stress was a value as large as 0.13 cN/dtex, but the temperature of the second peak of the thermal stress was 191 C and the second peak of the thermal stress was a value as small as 0.08 cN/dtex or less.

[0128]
Further, false-twist texturing was performed using the above-obtained fiber, and draw false-twist texturing was conducted under substantially the same conditions as those in Example 1, except that the draw ratio was changed to 1.35 times, so that the obtained textured yarn had an elongation of 40%.
Crimp properties of the obtained false twisted textured yarn are shown in Table 1.

[0129]
[Example 4]
Substantially the same procedure as in Example 1 was conducted except that the throughput rate for the polymer was changed, and that the intrinsic viscosity of the polytrimethylene terephthalate polymer was changed to 1.3 from 1.0 in Example 1, obtaining a solid multifilament having an oil agent applied thereto.

[0130]
Then, the solid multifilament was wound round the roll heated to 55 C at a circumferential speed which was increased to 2,160 m/minute, and further wound round a roll heated to 80 C so as to be drawn at a draw ratio of 1.2 times, and then, using a winder of a system that drives both a spindle and a touch roll, the resultant multifilament was wound up at a winding speed of Date Regue/Date Received 2024-04-17 2,500 m/minute, obtaining a cheese-form package having wound 100 dtex/36 filaments (f). The polymer throughput rate was controlled to adjust the final fineness. The obtained polymer had a glass transition point temperature of 52 C, whereas that in Example 1 was 51 C.

[0131]
Physical properties of the obtained fiber are shown in Table 1. A thermal stress of the obtained fiber was measured, and the results of the measurement showed that the temperature of the first peak of the thermal stress was 63 C and the first peak of the thermal stress was a value as large as 0.30 cN/dtex, but the temperature of the second peak of the thermal stress was 191 C and the second peak of the thermal stress was a value as small as 0.08 cN/dtex or less.

[0132]
Further, false-twist texturing was performed using the above-obtained fiber, and draw false-twist texturing was conducted under substantially the same conditions as those in Example 1, except that the draw ratio was changed to 1.2 times, so that the obtained textured yarn had an elongation of 40%.
Crimp properties of the obtained false twisted textured yarn are shown in Table 1.

[0133]
[Example 5]
Substantially the same procedure as in Example 1 was conducted except that the throughput rate for the polymer, and the heat treatment temperature after applying an oil agent, i.e., the fiber temperature during the drawing treatment were changed, obtaining a cheese-form package having wound 100 dtex/36 filaments (f).

[0134]
Specifically, the solid multifilament was wound round the heated roll at a temperature which was changed from 55 C to 40 C, at a circumferential speed which was reduced from 2,100 m/minute to 2,000 m/minute, and at a draw ratio which was still 1.3 times, and then wound round a roll heated to 100 C, instead of the heated roller at 80 C. Then, using a winder of a system that drives both a spindle and a touch roll, the resultant multifilament was wound up at a winding speed of 2,550 m/minute, obtaining a cheese-form package having wound 100 dtex/36 Date Regue/Date Received 2024-04-17 filaments (f). The polymer throughput rate was controlled to adjust the final fineness.

[0135]
Physical properties of the obtained fiber are shown in Table 1. A thermal stress of the obtained fiber was measured, and the results of the measurement showed that the temperature of the first peak of the thermal stress was 61 C and the first peak of the thermal stress was a value of 0.22 cN/dtex, which was larger than that in Example 1. Further, the results showed that the temperature of the second peak of the thermal stress was 191 C and the second peak of the thermal stress was a value as small as 0.08 cN/dtex or less, which was like that in Example 1.

[0136]
Further, false-twist texturing was performed using the above-obtained fiber, and draw false-twist texturing was conducted under substantially the same conditions as those in Example 1, except that the draw ratio was changed to 1.35 times, so that the obtained textured yarn had an elongation of 40%.
Crimp properties of the obtained false twisted textured yarn are shown in Table 1. The strength of the false twisted textured yarn was lowered, as compared to that in Example 1, but the crimp property was further excellent, as compared to that in Example 1.

[0137]
[Example 6]
Substantially the same procedure as in Example 1 was conducted except that the throughput rate for the polymer, and the heat treatment temperature after applying an oil agent, i.e., the fiber temperature during the drawing treatment were changed, obtaining a cheese-form package having wound 100 dtex/36 filaments (f).

[0138]
Specifically, the solid multifilament was wound round the heated roll at a temperature which was changed from 55 C to 60 C, at a circumferential speed which was reduced from 2,100 m/minute to 2,000 m/minute, and at a draw ratio which was still 1.3 times, and then wound round a roll heated to 100 C, instead of the Date Regue/Date Received 2024-04-17 heated roller at 80 C. Then, using a winder of a system that drives both a spindle and a touch roll, the resultant multifilament was wound up at a winding speed of 2,550 m/minute, obtaining a cheese-form package having wound 100 dtex/36 filaments (f). The polymer throughput rate was controlled to adjust the final fineness.

[0139]
Physical properties of the obtained fiber are shown in Table 1. A thermal stress of the obtained fiber was measured, and the results of the measurement showed that the temperature of the first peak of the thermal stress was 63 C, and the first peak of the thermal stress was 0.13 cN/dtex, which was like those in other Examples. The results showed that the temperature of the second peak of the thermal stress was 191 C, which was like those in other Examples, but the second peak of the thermal stress was a value as high as 0.09 cN/dtex.

[0140]
Further, false-twist texturing was performed using the above-obtained fiber, and draw false-twist texturing was conducted under substantially the same conditions as those in Example 1, except that the draw ratio was changed to 1.35 times, so that the obtained textured yarn had an elongation of 40%.
Crimp properties of the obtained false twisted textured yarn are shown in Table 1. The crimp property of the false twisted textured yarn was lowered, as compared to that in Example 1, but the false twisted textured yarn had more excellent crimp property than that in Comparative Example.

[0141]
[Comparative Example 1]
Substantially the same procedure as in Example 1 was conducted except that the throughput rate for the polymer was changed, and that after applying an oil agent, drawing was not conducted, obtaining a cheese-form package having wound 100 dtex/36 filaments (f). The polymer throughput rate was controlled to adjust the final fineness.

[0142]
Specifically, a solid multifilament having an oil agent applied thereto was obtained by the same method as in Example 1, and then the solid multifilament was wound round a roll heated to 55 C at a circumferential speed of 2,510 m/minute, and then Date Regue/Date Received 2024-04-17 wound up at a winding speed of 2,500 m/minute without being drawn, obtaining a cheese-form package.

[0143]
Physical properties of the obtained fiber are shown in Table 1. The fiber had a birefringence as small as 0.047 and a thermal stress maximum value as low as 0.05 cN/dtex. Further, the fiber had a high warm water shrinkage rate and poor storage stability.

[0144]
False-twist texturing was performed using the above-obtained fiber, and draw false-twisting at a draw ratio of 1.3 times was conducted under the same conditions as those in Example 1 so that the obtained textured yarn had an elongation of 40%, but yarn breaking frequently occurred in the draw false-twisting step, so that a sample was not able to be obtained.

[0145]
[Comparative Example 2]
Substantially the same procedure as in Example 1 was conducted except that after applying an oil agent, drawing was not conducted, but the winding speed was increased to improve the degree of orientation of the fiber, obtaining a cheese-form package having wound 100 dtex/36 filaments (f). The polymer throughput rate was controlled to adjust the final fineness.

[0146]
Specifically, a solid multifilament having an oil agent applied thereto was obtained by the same method as in Example 1, and then the solid multifilament was wound round a roll heated to 50 C at a circumferential speed of 3,010 m/minute, and then wound up at a winding speed of 3,000 m/minute, obtaining a cheese-form package.

[0147]
Physical properties of the obtained fiber are shown in Table 1. The fiber had a birefringence of 0.052, which was improved as compared to 0.047 in Comparative Example 1, but had a thermal stress maximum value as low as 0.06 cN/dtex. Further, the fiber had a high hot water shrinkage rate and poor storage stability.

[0148]

Date Regue/Date Received 2024-04-17 False-twist texturing was performed using the above-obtained fiber, and draw false-twisting at a draw ratio of 1.3 times was conducted under the same conditions as those in Example 1 so that the obtained textured yarn had an elongation of 40%.
Yarn breaking or the like did not occur and a sample was able to be obtained, but was poor in crimp property.

[0149]
[Comparative Example 3]
Substantially the same procedure as in Example 1 was conducted except that after applying an oil agent, drawing was conducted at a high draw ratio, obtaining a cheese-form package having wound 100 dtex/36 filaments (f).

[0150]
Specifically, a solid multifilament having an oil agent applied thereto was obtained by the same method as in Example 1, and then the solid multifilament was wound round a roll heated to 55 C at a circumferential speed of 900 m/minute which is a relatively low speed, and then drawn at a draw ratio as high as 3.1 times, and wound up at a winding speed of 2,800 m/minute, obtaining a cheese-form package.

[0151]
Physical properties of the obtained fiber are shown in Table 1. The fiber had a birefringence as high as 0.065, and the maximum peak temperature of the thermal stress was 190 C and the maximum peak of the thermal stress was as high as 0.20 cN/dtex. Further, the value of thermal stress in the temperature range of 100 C or lower was low.

[0152]
Further, false-twist texturing was performed using the above-obtained fiber, and draw false-twist texturing was conducted under substantially the same conditions as those in Example 1, except that the draw ratio was changed to 1.05 times, so that the obtained textured yarn had an elongation of 40%.
Yarn breaking or the like did not occur and a sample was able to be obtained, but was poor in crimp property.

[0153]
[Comparative Example 4]
Substantially the same procedure as in Example 1 was conducted except that after applying an oil agent, drawing and heat treatment were not conducted, but the winding speed was Date Regue/Date Received 2024-04-17 further increased, as compared to that in Comparative Example 2, to improve the degree of orientation of the fiber, obtaining a cheese-form package having wound 100 dtex/36 filaments (f).

[0154]
Specifically, a solid multifilament having an oil agent applied thereto was obtained by the same method as in Example 1, and then the solid multifilament was wound round a roll at a circumferential speed of 5,650 m/minute, and then wound up at a winding speed of 5,500 m/minute, obtaining a cheese-form package.

[0155]
Physical properties of the obtained fiber are shown in Table 1. The fiber had a birefringence as high as 0.082, and the specific gravity of the fiber polymer was as high as 1.332.
Further, the fiber had an elongation at break as low as 55% and a high fineness variation value.

[0156]
False-twist texturing was performed using the above-obtained fiber, and draw false-twist texturing was conducted under substantially the same conditions as those in Example 1, except that the draw ratio was changed to 1.1 times, so that the obtained textured yarn had an elongation of 40%. Yarn breaking or the like did not occur and a sample was able to be obtained, but was poor in crimp property.

Date Regue/Date Received 2024-04-17

[0157]
[Table 1]
Textured Polymer Fiber yarn Temperature in which Maximum 65 C hot Glass maximum value Intrinsic water Elongation transitionSpecificBirefrin- value of of Modulus U%
Crimp viscosity shrinkage at break cN/dtex hi%property point gravity gence thermal thermal dl/g rate %
C stress stress %
exists cN/dtex C
Example 1 1.00 51 1.325 0.051 61 0.20 13 2.3 90 0.4 A
Example 2 1.00 51 1.324 0.052 61 0.17 8 1.7 95 0.5 A
Example 3 1.00 51 1.320 0.054 60 0.13 3 0.4 100 0.6 A
Example 4 1.30 52 1.322 0.064 63 0.30 20 2.6 90 0.5 A
Example 5 1.00 51 1.325 0.053 61 0.22 20 0.7 100 0.5 A
Example 6 1.00 51 1.327 0.053 63 0.13 10 2.5 85 0.5 A
Comparative 1.00 51 1.318 0.047 58 0.05 56 -0.3 105 0.6 B
Example 1 Comparative 1.00 51 1.319 0.052 60 0.06 50 0.0 100 0.6 B
Example 2 Comparative 1.00 51 1.337 0.065 190 0.20 3 3.3 50 0.9 B
Example 3 Comparative 1.00 51 1.332 0.082 67 0.25 2 3.1 55 0.9 B
Example 4 Date Recue/Date Received 2024-04-17

[0158]
[Example 7]
Dimethyl terephthalate and 1,3-propanediol in a 1:2 molar ratio were charged in the same manner as in Example 1, obtaining a polymer which is comprised of trimethylene terephthalate repeating units (100 mol%), and which has an intrinsic viscosity of 1Ø

[0159]
The obtained polymer was dried by a general method so that the water content became 50 ppm, and then molten at 265 C, and extruded through a spinneret having 48 holes each having a diameter of 0.27 mm formed in a single line.

[0160]
The extruded molten multifilament was quickly cooled by applying thereto wind at a wind speed of 2.0 m/minute and changed to a solid multifilament, and then, using a guide nozzle, an oil agent containing 60% by weight of octyl stearate, 15% by weight of polyoxyethylene alkyl ether, and 3% by weight of potassium phosphate in the form of a water emulsion finishing agent having a concentration of 10% by weight was applied to the solid multifilament so that the amount of the oil agent applied became 0.6% by weight, based on the weight of the fiber.

[0161]
Then, the solid multifilament was wound round a roll heated to 50 C at a circumferential speed of 2,300 m/minute, and then wound round a roll heated to 80 C so as to be drawn at a draw ratio of 1.2 times, and then, using a winder of a system that drives both a spindle and a touch roll, the resultant multifilament was wound up at a winding speed of 2,700 m/minute, obtaining a cheese-form package having wound 73 dtex/48 filaments (f).

[0162]
Then, using the obtained yarn, a false twisted textured yarn was produced in a disc false-twisting system at a draw ratio of 1.3 times under the same conditions as those in Example 1.
Physical properties of the obtained textured yarn are shown in Table 2.

[0163]
[Example 8]
Substantially the same procedure as in Example 7 was conducted except that the spinneret was changed, and the molten Date Regue/Date Received 2024-04-17 polymer was extruded through a spinneret having 24 holes each having a diameter of 0.27 mm formed in a single line, obtaining a cheese-form package having wound 73 dtex/24 filaments (f).

[0164]
Then, the obtained fiber was subjected to false-twist texturing under the same conditions as those in Example 7, obtaining a false twisted textured yarn. Physical properties of the obtained textured yarn are shown in Table 2.

[0165]
[Example 9]
Substantially the same procedure as in Example 7 was conducted except that the spinneret was changed, and the molten polymer was extruded through a spinneret having 62 holes each having a diameter of 0.27 mm formed in a single line, obtaining a cheese-form package having wound 56 dtex/62 filaments (f).

[0166]
Then, the obtained fiber was subjected to false-twist texturing under the same conditions as those in Example 7, obtaining a false twisted textured yarn. Physical properties of the obtained textured yarn are shown in Table 2.

[0167]
[Example 10]
Substantially the same procedure as in Example 7 was conducted except that the spinneret was changed, and the molten polymer was extruded through a spinneret having 72 holes each having a diameter of 0.20 mm formed in a single line, obtaining a cheese-form package having wound 73 dtex/72 filaments (f).

[0168]
Then, the obtained fiber was subjected to false-twist texturing under the same conditions as those in Example 7, obtaining a false twisted textured yarn. Physical properties of the obtained textured yarn are shown in Table 2.

[0169]
[Example 11]
Substantially the same procedure as in Example 7 was conducted except that the spinneret was changed, and the molten polymer was extruded through a spinneret having 24 holes formed in a single line, wherein the spinneret has a cruciform cross-sectional shape having a slit width of 0.6 mm and a length of 1.2 mm, obtaining a cheese-form package having wound 73 dtex/24 filaments (f). The obtained yarn having an irregular shaped Date Regue/Date Received 2024-04-17 cross-section had an irregularity of 2.2.

[0170]
Then, the obtained fiber was subjected to false-twist texturing under the same conditions as those in Example 7, obtaining a false twisted textured yarn. Physical properties of the obtained textured yarn are shown in Table 2.

[0171]
[Example 12]
Substantially the same procedure as in Example 7 was conducted except that the spinneret was changed, and the molten polymer was extruded through a spinneret having 24 holes formed in a single line, wherein the spinneret has a triangular cross-sectional shape in which a slit having a slit width of 0.06 mm and a length of 0.5 mm extends from the center in three directions at an angle of 120 C, obtaining a cheese-form package having wound 73 dtex/24 filaments (f). The obtained yarn having an irregular shaped cross-section had an irregularity of 1.6.

[0172]
Then, the obtained fiber was subjected to false-twist texturing under the same conditions as those in Example 7, obtaining a false twisted textured yarn. Physical properties of the obtained textured yarn are shown in Table 2.

[0173]
[Example 13]
Substantially the same procedure as in Example 7 was conducted except that the spinneret was changed, and the molten polymer was extruded through a spinneret having 24 holes formed in a single line, wherein the spinneret has a flattened cross-sectional shape having a slit width of 0.14 mm and a length of 1.4 mm, obtaining a cheese-form package having wound 73 dtex/24 filaments (f). The obtained yarn having a flattened cross-section had a flatness of 3.4.

[0174]
Then, the obtained fiber was subjected to false-twist texturing under the same conditions as those in Example 7, obtaining a false twisted textured yarn. Physical properties of the obtained textured yarn are shown in Table 2.

[0175]
[Comparative Example 5]
Substantially the same procedure as in Example 7 was conducted except that after applying an oil agent, drawing was Date Regue/Date Received 2024-04-17 not conducted, obtaining a cheese-form package having wound 73 dtex/48 filaments (f).

[0176]
Specifically, melt spinning was conducted under the same conditions as those in Example 7, and the solid multifilament was wound round a roll heated to 50 C at a circumferential speed of 2,510 m/minute, and then wound up at a winding speed of 2,500 m/minute without being drawn, obtaining a cheese-form package.

[0177]
The temperature of the peak of the thermal stress of the obtained fiber was 55 C, and the peak of the thermal stress was 0.08 cN/dtex.
Further, the fiber had a lowest modulus of 0 cN/dtex at an elongation of 10 to 30% of the fiber.

[0178]
Then, to obtain a textured yarn, the obtained fiber was subjected to false-twist texturing under the same conditions as those in Example 7, but a textured yarn was not able to be obtained due to yarn breaking.

[0179]
[Comparative Example 6]
Substantially the same procedure as in Example 7 was conducted except that the spinneret was changed from that in Comparative Example 5, and the molten polymer was extruded through a spinneret having 12 holes each having a diameter of 0.30 mm formed in a single line, obtaining a cheese-form package having wound 108 dtex/12 filaments (f) (single fiber fineness:
9.0 dtex).

[0180]
The temperature of the peak of the thermal stress of the obtained fiber was 55 C and the peak of the thermal stress was 0.08 cN/dtex. Further, the fiber had the lowest modulus of 0 cN/dtex at an elongation of 10 to 30% of the fiber.

[0181]
Then, the obtained fiber was subjected to false-twist texturing under the same conditions as those in Example 1, obtaining a false twisted textured yarn. The obtained false twisted textured yarn had high crimp property, but had a large single fiber fineness such that the hand feeling was hard.
Physical properties of the obtained textured yarn are shown in Table 2.

[0182]

Date Regue/Date Received 2024-04-17 [Comparative Example 7]
The spinneret was changed from that in Example 7, and the molten polymer was extruded through a spinneret having 36 holes each having a diameter of 0.30 mm formed in a single line. Then, the resultant multifilament was wound round a roll heated to 50 C at a circumferential speed of 1,500 m/minute, and then drawn at a draw ratio of 2.0 times, and then wound round a roll heated to 130 C, and then, using a winder of a system that drives both a spindle and a touch roll, the resultant multifilament was wound up at a winding speed of 2,900 m/minute under the conditions at a draw ratio of about 2 times, obtaining a cheese-form package having wound 95 dtex/36 filaments (f).

[0183]
The temperature of the peak of the thermal stress of the obtained fiber was 190 C and the peak of the thermal stress was 0.20 cN/dtex. Further, the value of the thermal stress in the temperature range of 100 C or lower was low.
Further, the fiber had a lowest modulus of 3.3 cN/dtex at an elongation of 10 to 30% of the fiber.

[0184]
Both the crystallinity and the degree of orientation had proceeded due to heat drawing, and hence false-twisting could not be made using the disc false-twisting system in Example 7.
Therefore, false-twist texturing was conducted under the below-shown conditions for false-twisting, obtaining a false twisted textured yarn. In this instance, the texturing rate was as low as 100 m/minute, as compared to the texturing rate of 600 m/minute in Example 7.
Physical properties of the obtained textured yarn are shown in Table 2.
= Conditions for false-twisting Type of false twister: LS-2, manufactured by Mitsubishi Heavy Industries, Ltd. (pin false-twisting system) Number of revolutions of spindle: 27,500 rpm Number of false twists: 3,840 T/m First feed ratio: 0%
First heater temperature (contact type): 160 C
Second heater temperature (non-contact type): 150 C
Second feed ratio: +15%
Date Regue/Date Received 2024-04-17

[0185]
[Table 2]
Polymer Fiber Textured yarn Temperature in which Maximum Yarn maximum value Single Maximum Maximum breaking Intrinsic Cross- Total Breaking Elongation U%
value of of Modulus fiber crimp crimp during viscosity sectional fineness strength at break (Normal) thermal thermalcN/dtexfineness elongation stress false-dl/g shape dtex cN/dtex % %
stress stress dtex %
cN/dtex twist exists cN/dtex texturing C
Example 7 1.0 Circular 62 0.24 2.1 1.2 56 3.0 35 1.2 170 0.030 No Example 8 1.0 Circular 61 0.20 1.6 2.3 56 3.2 30 1.0 200 0.030 No Example 9 1.0 Circular 61 0.17 1.4 0.7 43 3.3 26 1.5 160 0.022 No Example 10 1.3 Circular 64 0.30 2.5 0.8 56 3.2 32 1.2 170 0.021 No Example 11 1.0 Cruciform 65 0.15 2.0 2.3 56 2.8 32 1.5 180 0.022 No Example 12 1.0 Triangular 61 0.17 1.4 2.3 56 3.0 30 1.5 160 0.030 No Example 13 1.0 Flat 61 0.18 1.8 2.3 56 2.7 31 1.5 160 0.021 No Comparative 1.0 Circular 55 0.08 0 - - - - -- - Yes Example 5 -comparative 1.0 Circular 55 0.08 0 6.9 83 3.1 31 1.1 170 0.028 No Example 6 Comparative 1.0 Circular 190 0.20 3.3 3.0 109 3.1 26 1.2 163 0.017 No Example 7 Date Recue/Date Received 2024-04-17 Industrial Applicability

[0186]
By the present invention, there can be achieved a polytrimethylene terephthalate fiber having a resistance to the process tension upon being textured and having high elongation, and a method for producing the same.
Further, there can be obtained a polytrimethylene terephthalate textured yarn which is advantageous not only in that yarn breaking is unlikely to occur during texturing, but also in that the yarn has high crimp property, and the invention is of extremely great commercial significance.
Reference Signs List

[0187]
R: Minimum circumcircle radius r: Maximum inscribed circle radius L: Long side of the circumscribing rectangle H: Short side of the circumscribing rectangle Date Regue/Date Received 2024-04-17

Claims

CA 03236004 2024-04-17

[Claim 1]
A fiber of polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90mo1% or more, the polytrimethylene terephthalate fiber satisfying all the following requirements (A) to (C):
(A) that, in the temperature-thermal stress curve of the fiber, a peak value of the thermal stress be present in the temperature range of from 40 to 100 C;
(B) that the peak value of the thermal stress in the requirement (A) be 0.1 to 0.8 cN/dtex; and (C) that the fiber has an elongation at break of 60 to 200%.
[Claim 2]
The polytrimethylene terephthalate fiber according to claim 1, which has the lowest modulus of 0.1 to 3 cN/dtex at an elongation of 10 to 30% of the fiber.
[Claim 3]
The polytrimethylene terephthalate fiber according to claim 1, which has a birefringence (An) of 0.03 to 0.08 and a specific gravity of 1.319 to 1.340.
[Claim 4]
A method for producing a polytrimethylene terephthalate fiber, comprising melting and solidifying polytrimethylene terephthalate, which is comprised of trimethylene terephthalate repeating units in an amount of 90mo1% or more, and then winding up the solidified polytrimethylene terephthalate at a winding speed of 1,000 m/minute or more and subsequently, heating the resultant polytrimethylene terephthalate using a heated roller at a temperature of the glass transition point of polytrimethylene terephthalate 20 C, and then drawing the heated polytrimethylene terephthalate at a draw ratio of 1.0 to 2.0 times, and further winding the drawn polytrimethylene terephthalate round a heated roller at 50 to 150 C, and then winding up the resultant polytrimethylene terephthalate at a speed of 2,000 to 4,800 m/minute.
[Claim 5]
A textured yarn which is obtained using the polytrimethylene terephthalate fiber according to any one of claims 1 to 3.

Date Regue/Date Received 2024-04-17
[Claim 6]
The textured yarn according to claim 5, which is a false twisted textured yarn.
[Claim 7]
A method for producing the textured yarn according to claim 5.

Date Regue/Date Received 2024-04-17