JP2001348731A - Polyester fiber with good false twistability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluff or yarn at the time of high-speed draw false twisting, which can be industrially produced by suppressing the occurrence of winding tightness and bulge, and by forming uniform fibers. Provided is a PTT-POY capable of performing stable high-speed stretch false twisting while suppressing occurrence of cutting. SOLUTION: The fibers are heat-treated under specific conditions to crystallize, the spinning conditions are optimized, and a special spinning method of winding at a very low tension is used. PTT-POY containing a specific amount of titanium oxide particles having a low Ug content and low agglomerates. It is possible to avoid winding and bulging, which are major problems when manufacturing PTT-POY, and to remarkably improve stretch false twisting at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to partially trimmed polytrimethylene terephthalate fiber suitable for draw false twisting and a cheese-like package thereof. More particularly, the present invention relates to partially trimmed polytrimethylene terephthalate fibers which can be industrially manufactured and can be subjected to stable high-speed draw false twisting and a cheese-like package thereof.

[0002]

2. Description of the Related Art Fibers using polytrimethylene terephthalate (hereinafter abbreviated as "PTT") have properties similar to polyamide such as low elastic modulus (soft texture), excellent elastic recovery and easy dyeing, and light resistance. It is an epoch-making polymer having properties similar to polyethylene terephthalate (hereinafter abbreviated as “PET”) fiber such as heat resistance, heat setting property, dimensional stability and low water absorption. One of the fiber forms that can make the most of the properties of such PTT fibers is a false twisted yarn. PTT fiber false twisted yarn is disclosed in Japanese Unexamined Patent Publication No. 9-78373.
As described in Japanese Patent Application Laid-Open No. H11-093026, compared with a fiber having a structure similar to PTT, for example, a polyester fiber such as PET fiber, the elastic recovery property and the softness are rich. This is because it is extremely excellent as a raw yarn.

However, in the above-mentioned publication, the raw yarn used for false twisting is a drawn fiber manufactured by a two-stage process such as spinning and drawing. Will be higher.
In addition, since the supplied raw yarn is a drawn yarn, it is not possible to perform high-speed drawing false twisting with high productivity. Similar to PET fiber, false twisting may be performed using partially oriented fiber (hereinafter abbreviated as “POY”) of PTT manufactured in a one-step process.

[0004] The prior art relating to PTT-POY used for false twisting is described in "Chemical Fibers Int."
47, published February 1997,
It is disclosed on pages 72-74. Here, a fiber is disclosed in which a polymer is extruded, cooled and solidified, a finishing agent is applied, and a fiber is wound at 3 to 6000 m / min without using a godet roll or through a cold godet roll. Japanese Patent Application Laid-Open No. H11-229276 discloses a PTT-POY having a specific finishing agent applied thereto, wound at 3300 m / min and having a birefringence of 0.059 and an elongation of 71%.

[0005] However, according to the study of the present inventors,
In the PTT-POY described in these, the yarn tube shrinks greatly on the yarn tube and tightens the yarn tube. Therefore, when winding the amount of yarn that is usually industrially produced, the yarn tube is deformed, and the cheese-like package is deformed. It becomes difficult to remove from the spindle of the winder. In such a situation, even if the deformation of the yarn tube is suppressed by using a high-strength yarn tube, a phenomenon called a bulge may occur on the package side surface, or the yarn may be tightly tightened by the inner layer of cheese. For this reason, the tension at the time of unwinding the yarn is increased, and the fluctuation of the tension is also increased, so that fluff and breakage of the yarn frequently occur at the time of false twisting, and uneven creasing and uneven dyeing occur.

[0006] As described above, the following two reasons can be considered as the reasons why the fibers shrink. 1) Unlike PET, PTT has a zigzag-like molecular structure and therefore has a low glass transition point (hereinafter abbreviated as “Tg”) of 30 to 50 ° C., so that the molecules move and shrink even at room temperature. It is. 2) Because the elastic recovery rate is high, the stress at the time of winding remains without being relaxed. According to the study of the present inventors, when stored at around room temperature, the physical properties of PET-POY hardly change, and the PTT-P
With OY, physical properties such as the boiling water shrinkage and the peak value of thermal stress change with time. For this reason, it is not possible to industrially perform false twisting, that is, it is not possible to stably produce false twisted yarns of the same quality without generation of fluff and yarn breakage over a long period of time.

As a technique for fixing the fiber structure, Japanese Patent Publication No. 63-42007 discloses a technique in which a polymer obtained by blending PET and PTT and / or polybutylene terephthalate is melt-discharged, solidified by cooling, and then heat-treated by a heating roller. Next, a method is disclosed in which the fiber is wound at a speed of 3500 m / min or more to produce a fiber having a breaking elongation (elongation at break) of 60% or less and a boiling water shrinkage of 7% or less. In this publication, as a comparative example, a PTT homopolymer and a PTT copolymer in which 10% by weight of PET were blended were heated to 180 ° C. in the same manner as described above and wound at 4000 m / min. A fiber having a boiling water shrinkage of about 33% and a boiling water shrinkage of about 4% is also disclosed. As described above, this publication describes a high-speed spinning method of heating with a roller and a PTT fiber obtained thereby.

However, an object of the invention described in this publication is a technique for using the obtained fiber as it is as a fiber for clothing, and at this time, promoting crystallization in order to improve the crimping property, thereby suppressing shrinkage. . For this reason, the obtained fiber is a drawn yarn having a low elongation, and cannot be subjected to high-speed draw false twisting. Further, according to the study of the present inventors, P
When POY is manufactured by TT, unevenness is likely to occur in the form and structure of the fiber as compared with PET or the like. For this reason, fiber property unevenness such as elongation at break tends to be large, and when high-speed drawing false twisting is performed, fluff and yarn breakage are likely to occur. Such a problem is not described or suggested at all in the above-mentioned documents or publications.

The following two factors are considered as causes of the unevenness of the fiber form and structure. 1) PTT has a low melting viscosity due to its low melting point, and
Due to the low g, in POY winding at high speed, the fibers are stretched non-uniformly and structural irregularities occur. 2) Compared to PET and PBT, PTT is more likely to agglomerate the titanium oxide added to suppress the gloss of the fiber. The aggregate of titanium oxide becomes a defect.

[0010] As a technique for improving the stability at the time of spinning, Korean Patent Publication No. 98051331 discloses that a polymer having an intrinsic viscosity of 0.55 to 0.75 is exposed to cooling air of 20 ° C. or less. A method for producing PTT-POY which is solidified and wound at a spinning speed of 4000 m / min or less is disclosed. In this publication, a polymer having a low intrinsic viscosity is used and low-temperature cooling air is used to suppress fluff and yarn breakage during spinning. However, when a polymer having a low intrinsic viscosity is used, the melt viscosity becomes low, so that fiber structure unevenness and fiber shape unevenness such as U% occur, and physical property unevenness such as elongation increases. Further, even if a low-temperature cooling air is used, it is not possible to sufficiently suppress the fiber form unevenness and structural unevenness. For this reason, when the fiber obtained in this publication is subjected to high-speed draw false twisting, fluff and yarn breakage frequently occur.

[0011] With respect to titanium oxide, US Pat.
No. 1188% by weight of titanium oxide
A PTT is disclosed. However, there is no mention of the technical meaning of titanium oxide dispersibility or the effect of titanium oxide dispersibility on fiber properties. The prior art discloses a PTT fiber that does not generate winding tightness or bulge, suppresses fluff during yarn twisting, and enables high-speed drawing false twisting to be performed industrially at high speed for a long period of time. Not at all.

[0012]

As a result of the study of the present inventors, PTT-P suitable for false twist processing manufactured in one-step process.
It has been found that the OY and its manufacturing method have the following problems in the prior art. (1) The winding yarn shrinks, the yarn tube is tightened, and the cheese-like package cannot be removed from the spindle of the winding machine, or a bulge occurs. For this reason, it is not possible to wind a cheese-like package having a yarn amount equivalent to that of PET manufactured industrially. (2) Even if PTT is stored at room temperature, physical properties such as boiling water shrinkage and thermal stress peak value change. Twisted yarn cannot be stably produced without generation of fluff and breakage.

(3) PTT has a low melt viscosity and a Tg
In the case of POY which is wound at a high speed because of its low molecular weight, the polymer is extruded from the spinneret and then stretched unevenly until it is solidified, which tends to cause structural unevenness. In addition, compared to PET or PBT, PTT is more likely to agglomerate the titanium oxide added to suppress the gloss of the fiber. For this reason, fiber structure unevenness and U
%, And unevenness in physical properties such as elongation is increased. When stretch false twisting is performed at a high speed, fluff and yarn breakage are likely to occur. SUMMARY OF THE INVENTION An object of the present invention is to provide a P which can be industrially manufactured and can be subjected to stable high-speed stretch false twisting.
It is to provide a TT fiber, a cheese-like package and a method for producing the same.

The problem to be solved in order to achieve the object of the present invention is to solve the above-mentioned problem (1) by suppressing the occurrence of tightening and bulging to enable industrial production, and PTT-PO whose physical properties do not change with time at room temperature to enable industrial stretch false twisting in response to the problem
In order to satisfy both the problem (3) and the industrial fiber production and post-processing, Y was produced by using a PTT polymer in which titanium oxide was not agglomerated and optimizing the draft at the time of spinning. An object of the present invention is to provide a PTT-POY having a small fiber property unevenness such as elongation due to a small structural unevenness and shape unevenness of the fiber.

[0015]

Means for Solving the Problems As a result of intensive studies, the present inventors have surprisingly found that using a PTT polymer in which titanium oxide is not aggregated, a spinning draft in a specific range is used.
Fibers with a specific range of orientation, crystallinity and fiber morphology and unevenness produced using a special spinning method that heats and crystallizes the fiber under specific conditions and winds it with extremely low tension, The present inventors have found that it is possible to avoid the occurrence of tightness and bulge, which are major problems in producing PTT-POY in one step, and to significantly improve post-workability such as stretch false twisting. Further, the fiber of the present invention, because the structure of the fiber is fixed by crystallization, physical properties hardly change over time, fluff over a long period of time, found that the false twisting process can be performed stably without occurrence of yarn breakage, The present invention has been completed.

That is, the present invention is as follows. 1. Polyester fiber (I) A polyester fiber comprising 90% by mole or more of polytrimethylene terephthalate composed of trimethylene terephthalate repeating units and satisfying the following requirements (A) to (G). (A) Density: 1.320 to 1.340 g / cm ³ (B) Birefringence: 0.030 to 0.070 (C) Peak value of thermal stress: 0.01 to 0.12 cN / dtex (D) Boiling water shrinkage: 3 to 40% (E) Elongation at break: 40 to 140% (F) 0.01 to 3% by weight of titanium oxide having an average particle size of 0.01 to 2 μm is contained, and titanium oxide particles are collected Agglomerates whose maximum length exceeds 5 μm are 12 / mg fiber or less. (G) U%: 0-2%

(II) A polyester fiber according to (I), wherein the wide-angle X-ray diffraction intensity in the direction perpendicular to the fiber axis satisfies the following expression. I ₁ / I ₂ ≧ 1.0 Here, I ₁ : 2θ = 15.5-16.5 ° maximum diffraction intensity I ₂ : 2θ = 18-19 ° average diffraction intensity (III) (I) or (I) 2. The method according to claim 1, wherein the standard deviation of the elongation at break is 0 to 10%.
And the polyester fiber according to 2.

2. Cheese-like package (I) The polyester fibers (I) to (II) of the present invention.
A cheese-like package, wherein any one of I) is wound and the bulge ratio is 20% or less. (II) In (I), the wound fiber
The winding width Q on the yarn tube is 50 to 300 mm and the weight is 2
A cheese-like package characterized by weighing not less than kg.

3. False twisting yarn (I) A false twisting process characterized in that 90 mol% or more is composed of polytrimethylene terephthalate composed of trimethylene terephthalate repeating units and satisfies the following requirements (H) to (K): yarn. (H) Stretch elongation: 150 to 300%, (I) Number of crimps: 4 to 30 / cm (J) Number of snares: 0 to 3 / cm (K) Oxidation with an average particle size of 0.01 to 2 μm 0.0 for titanium
Aggregates containing 1 to 3% by weight of titanium oxide particles and having a maximum length of more than 5 μm are not more than 12 aggregates / mg fiber.

(II) In (I), the number of crimps is 8 to
A false twisted yarn characterized by having a density of 25 yarns / cm. (III) In (I) and (II), the molecular weight is 300-8.
The oil agent containing 70-100% by weight of an aliphatic ester of 00 and / or a mineral oil having a redwood viscosity of 20-100 seconds at 30 ° C. is 0.5-5% by weight based on the false twisted yarn.
False twisted yarn attached.

4. Method for producing polyester fiber (I) In a method for melt-spinning polytrimethylene terephthalate in which 90 mol% or more is composed of trimethylene terephthalate recurring units, a polymer satisfying the following requirement (L) is used. Draft of 60-20
The molten multifilament extruded from the spinneret to be 00 was rapidly cooled to a solid multifilament and changed to 5
After performing a heat treatment at 0 to 170 ° C, 0.02 to 0.20
With a winding tension of cN / dtex, 2000 to 4000 m /
A method for producing a polyester fiber, comprising winding at a minute speed. (L) Titanium oxide having an average particle size of 0.01 to 2 μm is added to 0.0
Aggregates containing 1 to 3% by weight and aggregated with titanium oxide particles, and the maximum length of the aggregates exceeding 5 μm is 25 / mg polymer or less.

5. A method for producing false twisted yarn. (I) A method for producing a false twisted yarn, comprising using any of the polyester fibers (I) to (III) of the present invention. (II) Cheese-like package (I) to (II) of the present invention
A method for producing a false twisted yarn, characterized by using one of the above. (III) A method for producing a false twisted yarn according to (I) or (II), wherein a friction type false twisting machine is used.

Hereinafter, the present invention will be described in detail. (1) Polymer raw material, etc. (i) The polymer used in the present invention is polytrimethylene terephthalate (PTT) in which at least 90 mol% is composed of trimethylene terephthalate repeating units. It is. Here, PTT is a polyester containing terephthalic acid as an acid component and trimethylene glycol (also referred to as 1,3-propanediol) as a diol component. The PTT includes:
Less than 10 mol% may contain other copolymer components. Such copolymerization components include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 3,5
-Tetrabutylphosphonium dicarboxylate benzenesulfonate, tributylmethylphosphonium 3,5-dicarboxylate, 1,4-butanediol, neopentyl glycol, 1,6-hexamethylene glycol, 1,4-cyclohexanediol , 1,4
Ester-forming monomers such as cyclohexanedimethanol, adipic acid, dodecanediacid, and 1,4-cyclohexanedicarboxylic acid.

The polymer used in the present invention contains 0.01 to 3% by weight of titanium oxide having an average particle size of 0.01 to 2 μm, and is an aggregate in which titanium oxide particles are collected, and the longest part length thereof is It is necessary that the number of aggregates exceeding 5 μm is not more than 25 particles / mg polymer (this unit indicates the number of aggregates contained in 1 mg of polymer). By using such a polymer, it is possible to obtain the polyester fiber of the present invention which can suppress fluff and yarn breakage during spinning and post-processing as described later. In order to obtain such a polymer, titanium oxide is once added to a solvent and stirred, and then a titanium oxide dispersion obtained by removing agglomerates of titanium oxide using a centrifuge, a filter or the like is added to an arbitrary stage of polymerization. Is preferably added to the reaction product to complete the polycondensation reaction.

The titanium oxide used in the present invention is preferably an anatase type in that it has low hardness and good dispersibility in a solvent. The average particle size of titanium oxide is 0.01
２2 μm, preferably 0.05-1 μm
m. When the average particle size is less than 0.01 μm, it is difficult to obtain practically, and an aggregate is easily formed. On the other hand, if the average particle size exceeds 2 μm, it is not possible to reduce the number of aggregates having the longest portion exceeding 5 μm. The particle size distribution of the titanium oxide to be used is not particularly limited, but the particle size component of 1 μm or more is preferably 20% by weight or less of the whole,
More preferably, it is 10% by weight or less.

The titanium oxide used in the present invention is used by dispersing it in a solvent. The solvent may be dispersed once in water, alcohol or the like, but it is necessary to add it to a high temperature polymerization reaction system. More preferably, it is dispersed in 3-propanediol. Aggregates can be removed from the titanium oxide dispersed in the solvent only by centrifugation. However, in order to reduce the aggregates, it is desirable to remove the aggregates using a filter or the like after centrifugation. As the filter, a filter capable of collecting particles exceeding 5 μm is preferable. The titanium oxide dispersion thus obtained is preferably stirred or shaken until it is added to the reaction product. Titanium oxide precipitates in 1,3 propanediol,
This is for suppressing aggregation since it is easily aggregated.

The titanium oxide dispersion solution may be added to the reaction product at any stage of the polymerization. However, in order to suppress aggregation of the titanium oxide, the titanium oxide dispersion solution is not subjected to a long-term heat history, and the reaction product is made of titanium oxide. It is preferable to add the compound after the completion of the esterification reaction or transesterification reaction until the polycondensation reaction, which has a viscosity that allows good dispersion. If necessary for the polymer used in the present invention, various additives, for example, heat stabilizer, defoaming agent, tinting agent, flame retardant, antioxidant, ultraviolet absorber, infrared absorber, crystal nucleating agent, A fluorescent whitening agent, a matting agent other than titanium oxide, or the like may be copolymerized or mixed.

Intrinsic viscosity [η] of the polymer used in the present invention
Is preferably from 0.5 to 1.4, more preferably 0.80
~ 1.2. Within this range, fibers having excellent strength and spinnability can be obtained. When the intrinsic viscosity is less than 0.5, the melt viscosity is too low because the molecular weight of the polymer is too low, and in the production of POY to be wound at high speed,
After the polymer is extruded from the spinneret, it tends to be stretched unevenly until it is solidified. For this reason, it is difficult to obtain a fiber having small physical property unevenness such as elongation, which is the object of the present invention.
In addition, yarn breakage and fluff during spinning and processing are likely to occur, and it becomes difficult to develop the strength required for false twisted yarn. Conversely, if the intrinsic viscosity exceeds 1.4, the melt viscosity is too high, and melt fracture or poor spinning occurs during spinning, which is not preferable.

As a method for producing the polymer used in the present invention, a known method can be used as it is. That is, one or two or more metal salts such as titanium tetrabutoxide, calcium acetate, magnesium acetate, cobalt acetate, manganese acetate, and a mixture of titanium dioxide and silicon dioxide are used as starting materials, terephthalic acid or dimethyl terephthalate and trimethylene glycol. And react under normal pressure or pressure, then add a catalyst such as titanium tetrabutoxide, antimony trioxide, antimony acetate,
The reaction is carried out at 250 to 270 ° C under reduced pressure. Also, at any stage of the polymerization, it is preferable to add a stabilizer prior to the polycondensation reaction to improve whiteness, improve melt stability, and reduce the molecular weight of organic substances such as PTT oligomers, acrolein, and allyl alcohol having a molecular weight of 300 or less. This is preferable from the viewpoint of controlling generation.

(2) Polyester fiber (I) The polyester fiber of the present invention includes the following (A)
(G) must be satisfied. (A) Density: 1.320 to 1.340 g / cm ³ (B) Birefringence: 0.030 to 0.070 (C) Peak value of thermal stress: 0.01 to 0.12 cN / dtex (D) Boiling water shrinkage: 3 to 40% (E) Elongation at break: 40 to 140% (F) 0.01 to 3% by weight of titanium oxide having an average particle size of 0.01 to 2 μm is contained, and titanium oxide particles are collected Agglomerates whose maximum length exceeds 5 μm are 12 / mg fiber or less. (G) U%: 0-2%

In order to eliminate the tightening of the fiber, which is the first problem of the present invention, the fiber is crystallized and the molecule is fixed and the molecule is excessively fixed so that the yarn does not shrink greatly on the yarn tube. It is important that they are not oriented and strained. In order to enable stable production of false twisted yarn of the same quality for a long period of time without causing fluff and breakage, the second problem of the present invention is that fibers are crystallized and molecules are fixed. It is important that the elongation at break, the peak value of thermal stress, the shrinkage ratio of boiling water, and the like hardly change with time. Furthermore, the third problem of the present invention is that there is no generation of fluff or yarn breakage,
In order to enable stable high-speed draw false twisting, it is important to form a fiber that contains a specific amount of titanium oxide that does not become a defect and is uniform in the length direction.

Therefore, in order to attain all of these objects, it is necessary to make the fibers have a special structure having crystallinity and orientation within a specific range and uniform. As a generally known index of crystallinity, a fiber density measurement is suitable. Since the density of the crystal part is higher than that of the amorphous part, it can be said that the higher the density, the more crystallized. Observation of a crystal-derived peak by wide-angle X-ray diffraction can also be used as an index of crystallinity. As an index of the orientation, the birefringence of the fiber is suitable.

Suitable values that can express the molecular orientation state, tension state, and fixed state, which greatly affect the tightness of the winding and the aging of the fiber, include peak values of thermal stress, boiling water shrinkage, and elongation at break. I have. Further, as an index of fiber unevenness, the number and U% of aggregated titanium oxide are suitable. The standard deviation of the elongation at break can also be used as an index of fiber unevenness. Therefore, when the fiber density, the birefringence, the peak value of the thermal stress, the boiling water shrinkage, the elongation at break, and the titanium oxide and U% contained within the above ranges satisfy the above-mentioned ranges, the occurrence of tightness and bulge occurs for the first time. PT that can be produced industrially without any fluff or yarn breakage and can be drawn at high speed in a stable high-speed
It becomes T-POY.

(I) Density (A) The density must be 1.320 to 1.340 g / cm ³ . If the density exceeds 1.340 g / cm ³ , roll collapse will occur. Although the reason is not clear, since the fiber itself and the surface of the fiber are hardened by increasing the crystallinity of the fiber, the area when the yarn is brought into contact with the yarn is reduced,
It is considered that the coefficient of static friction between the yarns decreases. In addition, fluff and yarn breakage tend to occur during the false twisting, and it becomes impossible to perform the industrially stable false twisting. On the other hand, if the density is less than 1.320 g / cm ³ , the fibers are not fixed because the crystallization has not progressed sufficiently, and the fibers shrink and cause tightness, and the physical properties of the fibers change with time. In some cases, false twisted yarns of the same quality cannot be obtained under the same conditions over a long period of time. The density is preferably between 1.322 and 1.33.
6 g / cm ³ , more preferably 1.326 to 1.334
g / cm ³ .

(Ii) Relationship between the birefringence (B) and the peak value (C) of the thermal stress The birefringence of the fiber is 0.030-0.070, and the peak value of the thermal stress is 0.01-0. It must be 12 cN / dtex. If the birefringence of the fiber exceeds 0.070 or the peak value of the thermal stress exceeds 0.12 cN / dtex, the force to shrink the fiber is strong, and the fiber shrinks greatly after winding, resulting in tight tightening. I will. On the other hand, when the birefringence of the fiber is less than 0.030 or the peak value of the thermal stress is less than 0.01, the orientation is low and it is not crystallized. Physical properties change over time. In addition, if heat treatment is performed to suppress aging, the fibers become brittle. Therefore, in either case, the stretch false twisting cannot be performed industrially. The birefringence of the fiber is preferably 0.035 to
0.065, more preferably 0.040 to 0.0
60. In addition, the peak value of the thermal stress is preferably 0.1.
It is 015 to 0.10 cN / dtex, and more preferably 0.02 to 0.08 cN / dtex.

(Iii) Boiling water shrinkage (D) The boiling water shrinkage of the fiber must be 3 to 40%. If the boiling water shrinkage exceeds 40%, the crystallization has not progressed, and the structure is not fixed. Is changed, and it becomes impossible to produce a false twisted yarn stably without causing fluff and yarn breakage for a long period of time. If it is less than 3%, the fibers become brittle and fluff and yarn breakage occur frequently, so that false twisting becomes difficult. The boiling water shrinkage is preferably 4 to 20%, more preferably 5 to 1%.
5%.

(Iv) Elongation at break (E) Elongation at break needs to be 40 to 140%. If the elongation at break is less than 40%, the elongation is too low, so that fluff and yarn breakage are likely to occur during spinning or false twisting. When the elongation at break exceeds 140%, the degree of orientation of the fiber is too low and crystallization has not progressed, so that it is very easy to change with time, or the degree of orientation is too low and crystallization has progressed. Furthermore, since it becomes very brittle, false twisting cannot be performed industrially. The preferred range of the elongation at break is 50 to 120%.

The standard deviation of the breaking elongation is preferably 0 to 10%. The standard deviation of the elongation at break was determined from the results of measuring the elongation at break of the fiber for 20 samples.
When the standard deviation of the elongation at break exceeds 10%, the elongation unevenness of the fiber is large, and fluff and yarn breakage frequently occur during high-speed false twisting. The smaller the standard deviation, the better, and 0% is most preferable. A more preferred range of the standard deviation of the elongation at break is 0 to 7%, and particularly preferably 0 to 7%.
5%. When the elongation at break is measured for 20 samples, it is preferable that the following formula is satisfied. Minimum value of elongation (%)> Average value of elongation (%)-Standard deviation of elongation (%) x 2 By satisfying the above expression, fluff and yarn breakage during stretch false twisting can be extremely reduced. be able to.

(V) Titanium oxide (F) The polyester fiber of the present invention has an average particle size of 0.01 to 2 μm.
It is necessary that the number of aggregates containing 0.01 to 3% by weight of the titanium oxide and the aggregate of titanium oxide particles, the maximum length of which exceeds 5 μm is 12 / mg fiber or less. It is necessary that the fiber of the present invention contains 0.01 to 3% by weight of titanium oxide having an average particle size of 0.01 to 2 μm from the viewpoint of a matting agent and a reduction in friction coefficient. PTT has a larger coefficient of friction than PET or PBT. For this reason, fluff or yarn breakage tends to occur during spinning or false twisting. If the fibers contain titanium oxide, the coefficient of friction can be reduced, and fluff or yarn breakage during spinning or false twisting can be suppressed. The content of titanium oxide is 0.01
If it is less than the weight%, the effect of reducing the coefficient of friction becomes small,
Gloss is too high and cheap. On the other hand, if it exceeds 3% by weight, not only does the effect of reducing the coefficient of friction reach saturation, but also the titanium oxide peels off from the fibers and stains the spinning machine and winder. Preferably it is 0.03 to 2% by weight.

The fibers used in the present invention are aggregates in which titanium oxide particles are collected, and the aggregates having a longest portion length exceeding 5 μm are 12 fibers / mg fiber (this unit is 1 mg
2 shows the number of aggregates contained in the fibers of Example 1. ) Must be: By satisfying this condition, unevenness in physical properties such as elongation of the polyester fiber of the present invention can be suppressed.
It is more preferably at most 10 fibers / mg fiber, particularly preferably at most 7 fibers / mg fiber.

(Vi) U% (G) The polyester fiber of the present invention needs to have U% of 0 to 2%. U% is US made by Zellbeger Worcester Co., Ltd.
It is a value obtained from the variation of the mass of the fiber sample by TER · TESTER3. In this apparatus, a change in mass can be measured by a change in dielectric constant when a fiber sample is passed between electrodes. When passing through the apparatus at a constant speed, an uneven curve as shown in FIG. 1 is obtained. From this result, U% can be obtained according to equation (1) in FIG. When U% exceeds 2%, fluff and yarn breakage occur frequently during false twisting, and only false twisted yarns with large dyeing unevenness and crunch unevenness can be obtained. U% is preferably 1.5% or less,
More preferably, it is 1.0% or less. Of course, the lower the U%, the better.

(II) Physical Properties of Polyester Fiber (i) Strength The strength of the polyester fiber of the present invention is 1.3 cN / dt.
It is preferably ex or more. 1.3 cN / dtex
If it is less than 10%, the strength is low, so that when the yarn is unwound or false twisting is performed, fluff or yarn breakage occurs frequently. Preferably, it is 1.5 cN / dtex or more, and more preferably 1.7.
cN / dtex or more. (Ii) Observation of Crystal-Derived Diffraction Peaks by Wide-Angle X-Ray Diffraction In the present invention, it is preferable that the fibers are crystallized, that is, that crystal-derived diffraction peaks are observed by wide-angle X-ray diffraction.

Hereinafter, wide-angle X-ray diffraction will be described in detail with reference to the drawings. As a typical example of a diffraction pattern in a direction perpendicular to the fiber axis when X-rays are irradiated from the direction perpendicular to the fiber, a diffraction peak derived from a crystal is observed in FIG. FIG. 2- (b) shows the pattern when no diffraction peak derived from the crystal is observed.
Here, X-rays use CuKα rays. It is known that PTT takes a crystal form belonging to a triclinic form.
ym. Prepr. Jpn. , Vol. 26, p427
(1997)) When the fiber is crystallized,
In the vicinity of 2θ = 15.5 ° in the direction perpendicular to the fiber axis, (0
10) A diffraction peak derived from the plane is observed.

In the present invention, as shown in FIG. 2- (A), a diffraction image was observed depending on whether the wide-angle X-ray diffraction intensity in the direction perpendicular to the fiber axis satisfies the following expression. It was determined whether or not. I ₁ / I ₂ ≧ 1.0 where I ₁ : 2θ = 15.5 to 16.5 ° maximum diffraction intensity I ₂ : 2θ = 18 to 19 ° average diffraction intensity On the other hand, in FIG. Only a broad diffraction originating from an amorphous phase is observed, and a peak originating from a crystal as shown in FIG. In this case, the above expression is not satisfied.

Observation of a diffraction peak derived from the crystal by wide-angle X-ray diffraction indicates that the fiber is clearly crystallized and the structure is fixed. When no diffraction image derived from the crystals is observed, the fibers are not crystallized. Therefore, since the molecule is not fixed, the fiber shrinks and tightness occurs, and the physical properties of the fiber change with time, so that the false twisting cannot be stably performed over a long period of time.
The value of I ₁ / I ₂ is preferably at least 1.1, more preferably at least 1.2.

(Iii) Form of Fiber The polyester fiber of the present invention is preferably a multifilament. The total fineness is not limited, but is usually 5 to 400 d
tex, preferably 10 to 300 dtex, and the single fiber fineness is not limited, but is 0.1 to 20 dtex, preferably 0.5 to 10 dtex, and more preferably 1 to 5 dtex.
It is. The cross-sectional shape of the fiber is not limited, such as round, triangular, other polygonal, flat, L-shaped, W-shaped, cross-shaped, well-shaped, dogbone-shaped, and may be a solid fiber or a hollow fiber. Is also good.

(3) Cheese-like Package The fiber of the present invention is preferably wound around a cheese-like package. In order to follow modernization and rationalization of the false twisting process in recent years, it is preferable that the package is large-sized, that is, wound in a cheese-like package that can be wound in large quantities. In addition, when the yarn is unwound at the time of false twisting by using the cheese-like package, the fluctuation of the unwinding tension is reduced, and stable processing can be performed. (I) Bulge Ratio The cheese-like package in which the fiber of the present invention is wound preferably has a bulge ratio of 20% or less. FIG. 3A shows a cheese-like package (10) in which the yarn is wound into a desired shape.
0). The yarn is wound on a cylindrical yarn layer (104) having a flat end surface (102) formed on a winding core (103) such as a yarn tube.

The bulge is a bulging end face (102a) of the cheese-like package (100) which is generated when the winding thread slips due to a strong tightening force due to the contraction of the winding thread as shown in FIG. . The bulge ratio is a value calculated by measuring the winding width Q of the innermost layer and the winding width R of the bulging portion shown in FIG. 3A or FIG. It is. Bulge rate = {(R−Q) / Q} × 100% If the bulge rate of a cheese-like package exceeds 20%, the wound yarn will be broken during transportation, making it impossible to unwind, yarn breakage due to uneven unwinding tension, and fluff. , Stain spots and the like are likely to occur. In the worst case, the end face protrudes from the thread tube, so that it cannot be transported. Further, the tightening of the winding is large, and it often does not come off the spindle of the winding machine. Preferably, the bulge ratio is 16% or less, more preferably 10% or less. Of course, 0% is most preferable.

(Ii) Cheese-like Package Shape For industrial production, it is extremely important to reduce the frequency of replacing the yarn tube during spinning from the viewpoint of improving the working efficiency and reducing costs. In addition, in the false twisting process, after using a cheese-like package, it is used by connecting it to the next cheese-like package, but reducing the frequency of this connection is also extremely important from the viewpoint of improving work efficiency and reducing costs. It is. Therefore, the cheese-like package has 2
Preferably, at least 3 kg of the fiber of the present invention is wound, more preferably at least 3 kg, more preferably at least 5 kg.
That is all. If the weight is less than 2 kg, the frequency of the exchange of the tube and the frequency of the splicing are too high, so that it is difficult to industrially manufacture.

Further, when performing the draw false twist at a high speed, it is preferable to reduce the tension at the time of releasing the fiber from the yarn tube and to suppress the fluctuation of the tension. Since the PTT fiber has a higher friction coefficient than PET or the like, when the fiber is unwound from the yarn tube at a high speed, yarn breakage and fluff are likely to occur. Further, the tension tends to fluctuate, making it difficult to obtain a uniform false twisted yarn.
For this purpose, the winding width Q of the fiber on the yarn tube is set to 40 to 300 m.
m is preferable. If the winding width exceeds 300 mm, the tension at the time of release is increased, and the tension fluctuation is increased. If the winding width is less than 40 mm, the tension will be low, but the end of the wound yarn will be easily broken during unwinding. The winding width is more preferably 60 to 200 mm, and 70 to 200 mm.
150 mm is more preferred. The yarn tube has a diameter of 50 to 250
mm, more preferably 80 to 15 mm.
0 mm. The yarn tube used in the present invention may be made of any of resin such as phenolic resin, metal, and paper. In the case of paper, the thickness is preferably 5 mm or more.

(4) Method for Producing Polyester Fiber Next, a method for obtaining the polyester fiber and the cheese-like package of the present invention will be described. The polyester fiber of the present invention is basically prepared by rapidly cooling a molten multifilament extruded from a spinning port so that a draft at the time of spinning is 60 to 2,000, and changing the molten multifilament to a solid multifilament.
After heat treatment at 70 ° C., 0.02 to 0.20 cN /
It is obtained by winding at a speed of 2000 to 4000 m / min with a winding tension of dtex.

Hereinafter, a preferred method for producing the PTT fiber of the present invention will be described in detail with reference to FIGS. 1) First, PTT pellets dried to a moisture content of 100 ppm or less in the dryer 1 are supplied to the extruder 2 set at 250 to 290 ° C and melted. 250 to 2 for molten PTT
The liquid is sent to the spin head 4 set at 90 ° C. and measured by a gear pump. Thereafter, it is extruded into a spinning chamber 14 as a molten multifilament through a spinneret 6 having a plurality of holes mounted on a spinneret pack 5. The water content of the PTT pellet supplied to the extruder is preferably 50 ppm or less, more preferably 30 ppm or less, from the viewpoint of suppressing a decrease in the polymerization degree of the polymer. The temperatures of the extruder and the spin head need to be selected from the above ranges depending on the intrinsic viscosity and shape of the PTT pellet, but are preferably in the range of 255 to 280 ° C. If the spinning temperature is lower than 250 ° C, yarn breakage and fluff frequently occur,
Uneven yarn diameter may occur. When the spinning temperature is 2
Above 90 ° C., thermal decomposition becomes severe, and the resulting yarn is colored and does not exhibit satisfactory strength.

2) The draft at the time of spinning needs to be in the range of 60 to 2,000. Here, the spinning draft is a value represented by the following equation. Spinning draft = V ₂ / V _1, however, V _1: the linear velocity of the polymer when extruded from the spinning nozzle (m / min) V _2: First roll speed (m / min) (without the first roll , Winding Speed) The molten multifilament extruded from the spinneret is stretched before being rapidly cooled and converted into a solid multifilament. PTT has a lower melt viscosity and a lower Tg than PET or the like, and therefore has a longer time in a molten multifilament state and a longer drawing zone. For this reason, when the air resistance is large and fluctuates as in the case of POY which is wound at a high speed, it is likely to be stretched unevenly.

Therefore, the spinning draft, which indicates the draw ratio from extrusion to solidification, is very important for reducing the unevenness in physical properties such as U% and elongation. U% PT within the scope of the invention
T-POY can be manufactured. If the spinning draft exceeds 2,000, unevenness in physical properties such as U% and elongation becomes too large, and fluff and yarn breakage occur during high-speed false twisting. On the other hand, when the spinning draft is less than 60, the extrusion pressure becomes too high because the spinning diameter becomes too small, the melt fracture occurs and the unevenness of physical properties such as U% and elongation becomes large, and the winding speed is too slow. The degree of orientation and elongation may be out of the range of the PTT-POY of the present invention. For this reason, fluff or yarn breakage occurs at the time of false twisting at high speed. The spinning draft is preferably from 100 to 1500, and more preferably from 150 to 1000.

Further, the molten multifilament was quenched by passing it through a heat retaining area 7 having a length of 2 to 80 cm and maintained at an ambient temperature of 30 to 200 ° C. provided immediately below the spinneret to suppress rapid cooling. Preferably, it is changed to a solid multifilament. By passing through the heat retaining region 7, solidification unevenness is suppressed, and solidification unevenness (thickness unevenness, orientation degree unevenness and elongation degree unevenness) is not caused up to a high winding speed or the first roll speed. Can be changed. If the temperature in the heat retaining region is lower than 30 ° C., rapid cooling occurs and the solidification unevenness of the solid multifilament increases. On the other hand, if the temperature exceeds 200 ° C., thread breakage is likely to occur. The temperature of such a heat retaining region is preferably from 40 to 180 ° C, more preferably from 50 to 150 ° C. Further, the length of the heat retaining region is more preferably 5 to 30 cm.

3) Next, the solid multifilament is subjected to a heat treatment.
It is preferred that a finish is given by 0. By adding a finishing agent, the sizing, antistatic and slip properties of the fiber are improved, and the generation of fluff and yarn breakage during winding or false twisting is suppressed, or the wound cheese-like It becomes easy to keep the form of the package good.
Here, the finishing agent is a water emulsion in which an oil is emulsified using an emulsifier, a solution in which the oil is dissolved in a solvent, or the oil itself, which improves the fiber convergence, antistatic properties, slipperiness, and the like. . Here, the oil agent preferably includes a mixture containing at least one kind of an aliphatic ester, a mineral oil, and a polyether having a molecular weight of 1,000 to 20,000, and the sum of these is preferably 40 to 90% by weight, and the components are selected as necessary. Is preferred.

In the present invention, the oil agent is preferably applied to the fiber as a water emulsion having a concentration of 1 to 20% by weight. By using a water emulsion liquid, it becomes easy to suppress uneven adhesion of the oil agent and to improve the form of the wound yarn. The concentration of the water emulsion is more preferably 2 to 10% by weight, and particularly preferably 3 to 7% by weight. If the concentration is less than 1% by weight, since the amount of water volatilized by the heated first roll is too large, it is difficult to uniformly bring the fiber to a predetermined temperature due to heat of volatilization. As a result, unevenness in heat treatment occurs, and spots such as dyeing are generated. When the concentration exceeds 20% by weight, the viscosity of the finishing agent is high, and the amount of the finishing agent is reduced when a certain amount of the oiling agent is to be adhered to the fiber, so that it is difficult to uniformly apply the oiling agent to the fiber. .

It is preferable that the oil agent is applied in an amount of 0.2 to 3% by weight based on the weight of the fiber. If it is less than 0.2% by weight,
The effect of the oil agent is small, and the yarn breaks down due to static electricity, and the yarn breaks or fuzzes due to friction. 3% by weight
If the ratio exceeds the above range, the resistance of the fibers during running becomes too large, and the oil agent adheres to the rolls, hot plates, guides, etc., and contaminates them. To use for false twisting, 0.25 to 1.
It is preferably 0% by weight, particularly preferably 0.3 to 0.7% by weight. Of course, a part of the oil agent may permeate into the fiber.

As a method for applying the finishing agent, a method using a known oiling roll or a method described in, for example, JP-A-59-11
Although a method using a guide nozzle disclosed in Japanese Patent No. 6404 or the like can be used, a method using a guide nozzle is preferable in order to suppress the occurrence of yarn breakage and fluff due to friction of the finish applying device itself. The location at which the finish is applied to the fibers may be in the chamber 14, in the zone 15 for heat treating the fibers, before the first roll 11, or anywhere between these zones. The position closest to the spinneret immediately after being cooled to room temperature and changed to the solid multifilament 8 is preferable. This is because the fibers are bundled at the same time as the finishing agent is applied, so that the closer this position is to the spinneret, the lower the air resistance can be, and it is possible to suppress the occurrence of yarn breakage and fluff.

4) The wound fiber preferably contains 0.5 to 5% by weight of water. This water may be included in the fiber from the water contained in the finish, or before winding, may be applied separately from the finish using a method using a guide nozzle similar to that for applying the finish. I don't care. The amount of water contained in the fiber is more preferably from 0.7 to 4% by weight, particularly preferably from 1 to 3% by weight. When the moisture content is in this range, it becomes easy to obtain a good-form package free of occurrence of traversal of the winding package end face and generation of bulge.

5) Next, the solid multifilament 8 is subjected to a heat treatment by the first roll 11 or the like in the zone 15 for heat treating the fiber. Here, reference numeral 12 denotes a free roll that is not driven by itself. The polyester fiber of the present invention may be directly wound up by a winder after heat treatment with a heater or the like without using a roll or the like. It is preferable to take up with. This is because adjusting the speed of the roll and the winder makes it easier to control the winding tension.

As a heat treatment method of the fiber, in addition to the method using only the first roll 11 in FIG. 4, a method of heating by the first roll 11 and / or the second roll 16 in FIG. (B) a method of heating with any one or a plurality of rolls from the first Nelson roll 17 to the second Nelson roll 18, the first heater 19 of FIG.
And / or a method of heating by the second heater 20, FIG.
(D) a method of heating with the first heater 19, and the like. In the case of FIGS. 5- (C) and (D), the heat treatment may be performed by a roll in addition to the heat treatment by the heater.

As a heater used for heating, either a contact type heater or a non-contact type heater may be used. Alternatively, a method using a heated gas may be used. Among them, the method using a heating roll is most preferable because the speed adjustment of the roll and the winder and the heat treatment can be performed simultaneously. In the present invention, heating with a roll means heating with a self-driven roll and not heating with a free roll. Of course, heating with a free roll may be performed.

The temperature of the heat treatment needs to be 50 to 170 ° C. If the temperature is lower than 50 ° C., the fiber cannot be increased to a sufficient crystallinity.
Since the physical properties change over time, false twisting cannot be performed industrially. On the other hand, if the temperature exceeds 170 ° C., yarn breakage or fluff occurs during spinning, crystallization proceeds excessively, the coefficient of static friction between fibers decreases, and the bulge ratio increases, or false twisting becomes difficult. I do. The heat treatment temperature is
Preferably it is 60-150 degreeC, More preferably, it is 80-13.
0 ° C.

The heat treatment time is preferably from 0.001 to 0.1 second. The term “heat treatment time” as used herein refers to the total time when heat treatment is performed with a plurality of rolls or heaters. If the heating time is less than 0.001 second, the heat treatment time is short and sufficient crystallization cannot be promoted.
Winding and bulges are liable to occur and change over time. On the other hand, if the heating time exceeds 0.1 second, crystallization proceeds too much, the coefficient of static friction between fibers becomes too small, and the resulting cheese-like package has a large bulge. In the present invention, the degree of crystallinity increases even when the heat treatment temperature increases, the heat treatment time increases, and the winding speed increases. Therefore, it is more preferable to select a heat treatment time according to the heat treatment temperature and the winding speed.

6) The multifilament that has been subjected to the heat treatment is wound by using the winder 13. Winding speed is 20
It is necessary to be 00 to 4000 m / min. If the winding speed is less than 2000 m / min, the orientation of the fiber is low, so that the physical properties change over time, and the fiber becomes brittle even if the heat treatment is reinforced, making it difficult to handle and false twist the fiber.
On the other hand, when the speed exceeds 4000 m / min, the orientation and crystallization of the fiber are excessively advanced, and the tension during winding cannot be reduced.
The fiber shrinks greatly on the yarn tube, causing tight winding. Preferably, it is 2200-3800 m / min, more preferably 2500-3600 m / min. In the present invention, the tension at the time of winding is 0.02 to 0.20 c.
It needs to be N / dtex.

If a conventional melt spinning of PET or nylon is used to wind the yarn at such a low tension, the running of the yarn becomes unstable, and the yarn may come off from the traverse of the winder to cause yarn breakage. Or a switching error occurs when the winding yarn is automatically switched to the next yarn tube. However,
Surprisingly, PTT fiber does not cause such a problem even if it is wound with an extremely low tension as in the present invention, and a cheese-like package having a good winding shape is obtained for the first time with a low tension because the tension is low. be able to. It is considered that the reason why the winding can be performed stably even at such a low tension is due to the low elastic modulus and the high elastic recovery characteristic of the PTT fiber.

When the tension is less than 0.02 cN / dtex, the tension is too weak, so that the traverse with the traverse guide of the winding machine cannot be made good, and the winding form becomes poor, the yarn comes off from the traverse, and the yarn is removed. Cutting may occur. On the other hand, when it exceeds 0.20 cN / dtex, even if the fiber is heat-treated and wound up, tight tightening occurs. The tension at the time of winding is preferably 0.025.
0.15 cN / dtex, more preferably 0.03 to
0.10 cN / dtex. It is preferable to adjust the peripheral speed of the roll when installing the roll before the winder so that the winding tension falls within the above range. This roll speed is preferably 0.80 to 1.1 times the normal winding speed.

In the present invention, entanglement treatment may be performed as necessary in the spinning process. The confounding process is performed before the finish is applied.
It may be performed before heat treatment or before winding, or at a plurality of places. The winding machine used in the present invention may be any of a spindle driving system, a touch roll driving system, and a system in which both the spindle and the touch roll are driven, but both the spindle and the touch roll are driven. This type of winder is preferable for winding a large amount of yarn.

When only one of the touch roll and the spindle is driven, the other is rotated by the friction from the drive shaft. Therefore, the surface speed differs between the thread tube attached to the spindle and the touch roll due to slippage. I will. For this reason, when the thread is wound from the touch roll to the spindle, the thread is stretched or loosened, the tension is changed, the winding appearance is deteriorated, or the thread is easily rubbed and damaged. By driving both the spindle and the touch roll, it is possible to control the difference between the surface speeds of the touch roll and the thread tube, reduce slippage, and improve the yarn quality and winding appearance. it can.

It is preferable that the winding angle when winding the fiber is 3.5 to 8 °. When the twill angle is less than 3.5 °, the yarns do not intersect so much that they are slippery, and the twill drops and bulges are likely to occur. On the other hand, when the angle exceeds 8 °, the diameter of the end portion becomes larger than that of the central portion because the amount of yarn wound around the end portion of the yarn tube increases. For this reason, when winding, only the end comes into contact with the touch roll and the yarn quality deteriorates.Moreover, the tension fluctuation when unwinding the wound yarn becomes large, and fluff and yarn breakage occur. It happens frequently.
The twill angle is more preferably 4 to 7 °, particularly preferably 5 to 7 °.
6.5 °.

7) The PTT-POY of the present invention can be made into a false twisted yarn having a very soft and good elastic recovery and its durability by performing stretch false twisting. False twisted yarn has a stretch rate of 150 to 300%,
The number of crimps is 4-30 / cm, the number of snares is 0-3 / c
m is preferable. By setting the stretch ratio, the number of crimps, and the number of snals in such a range, PTT is excellent in softness and elastic recovery, which are the characteristics of PTT, and has good processability such as weaving and knitting and has good surface properties. It can be a false twisted yarn that can be obtained.

If the stretch ratio is less than 150% or the number of crimps is less than 4 / cm, the processed yarn will be inferior in softness and elastic recovery, or the bulkiness will be insufficient, resulting in a bulging feeling. It becomes a processing yarn of the filament touch that lacks. On the other hand, when the stretch ratio exceeds 300% or the number of crimps exceeds 30 pieces / cm, the processability of weaving and the like deteriorates, and the resulting fabric has a large feeling of roughness and flutter. However, the fabric does not fully utilize the soft texture of PTT. More preferably, the stretch ratio and the number of crimps are each 180 to
250%, 8 to 25 particles / cm. If the number of snares exceeds 3 / cm, the untwisted portions become entangled with each other when the false twisted yarn is unwound from the wound state, and the unwinding tension becomes excessive. The yarn breaks and unwinding becomes impossible. Alternatively, even if the yarn is not broken, the fluctuation of the unwinding tension is increased, and the weaving and knitting properties are reduced. The number of snares is 0
２2 / cm is more preferable, and of course 0 / cm is most preferable.

The false twisted yarn of the present invention may be used as a PTT-P
Similar to OY, an agglomerate containing 0.01 to 3% by weight of titanium oxide having an average particle diameter of 0.01 to 2 μm, and an aggregate in which titanium oxide particles are collected, and the longest portion of which is longer than 5 μm Should be 12 fibers / mg fiber or less. As a result, not only a false twisted yarn can be obtained industrially stably, but also woven knitting can be stably performed industrially. Such a false twisted yarn is the P yarn of the present invention.
It can be obtained by using TT-POY and a cheese-like package. Contains a specific amount of non-agglomerated titanium oxide, and has small physical property unevenness such as U% of fiber and unevenness in elongation.
This is because an appropriate draw ratio and a ratio of disk speed / yarn speed can be selected because the unwinding tension from the cheese-like package is low and the tension unevenness is small.

As a method of the stretch false twisting, any method such as a pin type, a friction type, a nip belt type, and an air twist type generally used may be used, but a friction type and a nip belt type which can increase a processing speed are used. preferable. The processing speed is preferably 400 m / min or more, more preferably 500 m / min or more from the viewpoint of productivity. The processing conditions are not particularly limited, and can be appropriately selected from the known condition ranges exemplified below. The false twisted yarn is used as a fabric by weaving or knitting, but it is preferable to adhere the oil agent again before winding the false twisted yarn in order to improve the weaving and knitting properties.
This oil agent may be attached to the fiber by being mixed with the oil agent to be attached at the time of spinning. In this case, the amount of the oil agent attached to the false twisted yarn is the sum of the oil agent attached during spinning and the oil agent attached during false twisting.

The oil used herein has a molecular weight of 300
-800 aliphatic esters and / or mineral oil having a redwood viscosity of 20-100 seconds at 30 ° C.
It is preferable to contain 0 wt%. When the molecular weight of the aliphatic ester is less than 300 or the redwood viscosity of the mineral oil is 20
If the time is less than seconds, the viscosity is too low, so that the knitting and weaving properties cannot be enhanced. On the other hand, if the molecular weight of the aliphatic ester exceeds 800 or the viscosity of the redwood of the mineral oil exceeds 100 seconds, the viscosity is too high, so that fluff and yarn breakage are liable to occur during knitting and weaving, and the knitting and weaving equipment becomes dirty. Easy to do. More preferably, it comprises an aliphatic ester having a molecular weight of 400 to 700 and / or a mineral oil having a redwood viscosity at 30 ° C. of 30 to 80 seconds. If the content of the aliphatic ester and / or the mineral oil in the oil agent is less than 70% by weight, the slipperiness and stain resistance are deteriorated. The content rate is
More preferably, it is 90 to 99.5% by weight. In order to enhance the weaving and knitting properties, it is preferable that 0.5 to 5% by weight of such an oil agent is adhered to the false twisted yarn.
More preferably, 3% by weight is attached.

<Example of False Twisting Conditions in Friction Type> False Twisting Speed: 300 to 1000 m / min False Twisting Temperature: 100 to 200 ° C. Draw Ratio (Stretching Ratio): Adjusted to Elongation of 40 to 50% (Usually 1.05 to 2.0 times) Twisted disc: ceramic, urethane, etc. Disc speed / yarn speed ratio (D / Y ratio): 1.7 to 3

[0078]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to examples and the like, but needless to say, the present invention is not limited by the examples and the like. The main measured values in the examples were measured by the following methods. (1) Content of Titanium Oxide The content of titanium oxide is calculated from the atomic weight of Ti element and oxygen element by measuring the amount of Ti element using a high frequency plasma emission spectrometer IRIS-AP manufactured by Thermojar Ler Ash. I asked. The analysis sample was prepared as follows. 0.5 g of Erlenmeyer flask with polymer or fiber and 15 ml of concentrated sulfuric acid were added and decomposed for 3 hours on a 150 ° C. hot plate and 2 hours on a 350 ° C. hot plate. After cooling, 5 ml of aqueous hydrogen peroxide was added to oxidize and decompose. The solution was concentrated to 5 ml, 5 ml of an aqueous solution of concentrated hydrochloric acid / water (1: 1) was added, and 40 ml of water was added. A sample was used.

(2) Average Particle Size of Titanium Oxide A polymer or fiber section was cut at 2500 to 2000 using a transmission electron microscope JEM-2000FX manufactured by JEOL.
Observation was performed at a magnification of 0, and photography was performed. Next, using an image analyzer IP-1000 manufactured by Asahi Kasei, a circle-equivalent system was determined from the area of each titanium oxide particle photographed and taken as an average particle diameter. (3) Aggregate of titanium oxide 1 mg of polymer or fiber is divided into two pieces of 15 mm × 15 mm
And put it on a hot plate.
Melted at ℃. After the melting, a load of 100 g was applied to the cover glass, and the melt was spread tightly between the two cover glasses so as not to protrude from the cover glass, and was poured into cooling water and rapidly cooled. This sample was magnified 200 times using an optical microscope, and the entire area of the resin or fiber was observed. At this time, the number of objects having the longest part length exceeding 5 μm was counted. The same operation was performed five times, and the average value was defined as the number of aggregates of titanium oxide.

(4) Intrinsic Viscosity The intrinsic viscosity [η] was measured using an Ostwald viscometer,
The ratio ηsp / C of the specific viscosity ηsp in the o-chlorophenol solvent and the concentration C (g / 100 ml) in the o-chlorophenol solvent was extrapolated to zero concentration, and determined by the following equation. (5) Density Based on JIS-L-1013, carbon tetrachloride and n-
The measurement was performed by a density gradient tube method using a density gradient tube prepared with heptane.

(6) Birefringence Fiber Handbook-Raw Material Edition, p. 969 (5th printing, Maruzen Co., Ltd., 1978), using an optical microscope and a compensator, from the retardation of polarized light observed on the fiber surface. (7) Peak value of thermal stress KE-2 manufactured by Kanebo Engineering was used. The measurement was carried out at an initial load of 0.044 cN / dtex and a heating rate of 100 ° C./min. The obtained data is plotted with temperature on the horizontal axis and thermal stress on the vertical axis to draw a temperature-thermal stress curve. The value of the maximum point of the thermal stress was defined as the peak value of the thermal stress.

(8) Boiling water shrinkage ratio Skew shrinkage ratio was determined based on JIS-L-1013. (9) Strength (fiber rupture strength), elongation (fiber rupture elongation) Using Tensilon manufactured by Orientec Co., Ltd., which is a constant speed elongation type tensile tester based on JIS-L-1013,
The measurement was performed on 20 fiber samples at a grip interval of 20 cm and a pulling speed of 20 cm / min. The average value at this time was defined as strength and elongation at break. At the same time, the standard deviation and minimum value of elongation were also determined.

(10) U% U% is USTER · T manufactured by Zellbeger Worcester Co., Ltd.
It was determined by measuring with ESTER3 under the following conditions. Measurement speed: 100m / min Measurement time: 1 minute (U%) (Yarn length = 100m) Number of measurements: 2 Twist type: S twist

(11) Wide-angle X-ray diffraction (counter method) Observation was performed under the following conditions using a wide-angle X-ray diffractometer Rotaflex RU-200 manufactured by Rigaku Corporation (currently Rigaku Corporation). X-ray type: CuKa line Output: 40 KV 120 mA Goniometer: manufactured by Rigaku Corporation (currently Rigaku Corporation) Detector: scintillation counter Count recording device: RINT2000, online data processing system Scanning range: 2θ = 5 to 40 ° sampling interval : 0.03 ° Integration time: 1 second As the diffraction intensity, a true diffraction intensity obtained from the diffraction intensity obtained by measuring the sample and the air scattering intensity according to the following formula was used. True diffraction intensity = sample diffraction intensity-air scattering intensity

(12) Adhesion rate of oil agent Based on JIS-L-1013, the fiber was washed with diethyl ether, the diethyl ether was distilled off, and the amount obtained by dividing the amount of pure oil agent adhering to the fiber by the fiber weight was calculated. The adhesion rate of the oil agent was used. (13) Bulge ratio Yarn layer (104) shown in FIG. 3- (A) or FIG. 3- (B)
Of the innermost layer and the winding width R of the bulging portion
Was measured and calculated according to the following equation. Bulge rate = {(RQ) / Q} x 100%

(14) Crimp Number of False Twisted Yarn According to JIS-L-1015, five false twisted yarns are treated in hot water at 90 ° C. for 20 minutes, and then the number of false twisted yarns per 25 mm The number of crimps was counted and the average was determined.
The value obtained by converting this result to the number of fatigues per cm was used. (15) Stretching and elongation rate of false twisted yarn Based on JIS-L-1090, 20% in hot water at 90 ° C.
After the treatment for 5 minutes, the stretch and elongation (%) of the false twisted yarn was determined by the stretch A method.

(16) Number of Snals in False Twisted Yarn 1.764 × 10 ⁻³ cN / dte was added to the false twisted yarn collected from the winding package without crimping.
Under a load of x, an enlarged photograph of the side surface of the false twisted yarn was taken, and a portion where one filament was twisted to form a loop fluff was counted as a snare. Thread length 75mm
The average value obtained by measuring the intervening snare five times was determined, and the value converted to the number of snals per cm was used. (17) Redwood viscosity Measured according to JIS-K2283-1956.

[0088]

Examples 1 to 4 Dimethyl terephthalate and 1,3-propanediol were charged at a molar ratio of 1: 2, and titanium tetrabutoxide corresponding to 0.1% by weight of dimethyl terephthalate was added. The transesterification reaction was completed at ℃. Next, titanium tetrabutoxide was further added at 0.1% by weight of the theoretical polymer amount, and titanium dioxide was added at 0.5% by weight of the theoretical polymer amount, and reacted at 270 ° C. for 3 hours. Titanium dioxide has an anatase type crystal form having an average particle size of 0.2 μm and is converted to 1,3-propanediol by 20%.
% By weight with a homogenizer and 6000 rpm
Was centrifuged for 30 minutes and added as a dispersion filtered through a 5 μm membrane filter until just before the addition.

The intrinsic viscosity [η] of the obtained polymer is 0.1.
9, titanium oxide having an average particle size of 0.7 μm was contained at 0.5% by weight, and the aggregate of titanium oxide having a longest portion length exceeding 5 μm was 12 / mg polymer. The obtained polymer was dried by a conventional method using the apparatus shown in FIG. 4 to make the water content 50 ppm, and then melted at 265 ° C. to form a single array in which 36 holes having the spinning diameter shown in Table 1 were opened. Extruded through the spinneret. The extruded molten multifilament passed through a heat retaining region having a length of 5 cm and a temperature of 100 ° C., and was rapidly cooled by applying a wind of 0.4 m / min to be converted into a solid multifilament.

Using a guide nozzle for the solid multifilament, an oil containing 60% by weight of octyl stearylate, 15% by weight of polyoxyethylene alkyl ether and 3% by weight of potassium phosphate was used as a water emulsion finish having a concentration of 5% by weight. After applying an oil agent adhesion rate to the fiber of 0.7% by weight, the solid multifilament is wound around the first roll at the temperature and speed shown in Table 6 six times and heat-treated. Using a winder that drives both touch rolls, the winding speed shown in Table 1,
The winding tension is 124 mm in diameter and 5 mm in twill angle.
6 kg was wound around a 90 mm paper thread tube with a winding width of 90 mm to obtain a cheese-like package in which fibers of 90 dtex / 36 f were wound. The spinning drafts at this time were all within the scope of the present invention. The wound cheese-like package was easily removed from the spindle of the winder, and the bulge ratio was in a good range. The physical properties of the obtained fibers are shown in Table 2. All of the obtained fibers were within the scope of the present invention, and no yarn breakage or fluff was observed during the spinning process.

Using the fibers obtained in Examples 1 to 3, using an FK-6 false twist processing machine manufactured by Ishikawa Seisakusho, using seven ceramic twisted disks, a processing speed of 500 m / min, and a heater temperature of 170 ° C. , Disk speed / yarn speed ratio (D / Y ratio)
2.3 Stretch false twisting was performed at a draw ratio (drawing ratio) at which the elongation of the processed yarn was 45%. At this time, an oil agent containing 98% by weight of a mineral oil having a redwood viscosity of 60 seconds and 2% by weight of potassium phosphate was applied to the false twisted yarn immediately before winding, so as to be 2% by weight. False twisting was performed without fluff or yarn breakage, and excellent false twisting yarn having the crumpling form and characteristics comparable to PET and having the softness and elastic recovery characteristic of PTT was obtained. The obtained processed yarn had very good weaving and knitting properties. Even after 3 months, almost no change in physical properties over time was observed, and when the stretch false twisting was performed, a false twisted yarn of the same quality could be obtained under the same conditions.

[0092]

Example 5 A fiber was obtained in the same manner as in Example 1 except that 2.0% by weight of the theoretical polymer amount of titanium dioxide was added. The intrinsic viscosity [η] of the polymer used for spinning is 0.9, and 2.0% by weight of titanium oxide having an average particle size of 0.7 μm is used.
The number of aggregates of titanium oxide contained and the maximum length of which exceeded 5 μm was 15 pieces. The cheese-like package from which the fiber was wound was easily removed from the spindle of the winder, and the bulge ratio was in a favorable range. The physical properties of the obtained fibers are shown in Table 2. All of the obtained fibers were within the scope of the present invention, and no yarn breakage or fluff was observed during the spinning process. Using the obtained fiber, stretch false twisting was performed in the same manner as in Example 1, and no fluff or thread break was observed during false twisting, and it had a crumpling form and characteristics similar to PET. In addition, an excellent false twisted yarn having the softness and elastic recovery characteristic of PTT can be obtained.

[0093]

Comparative Examples 1 to 5 Fibers were obtained in the same manner as in Example 1 under the conditions shown in Table 1. The physical properties of the obtained fibers are shown in Table 2. In Comparative Example 1, since the winding speed was low, the birefringence and the density were out of the range of the present invention. Using this fiber, stretch false twisting was performed in the same manner as in Example 1, but fluff and breakage occurred frequently, and a false twisted yarn could not be obtained. In Comparative Example 2, the density was out of the range of the present invention because no heating was performed, and in Comparative Example 3, the winding tension could not be reduced due to the high winding speed, and the density exceeded the range of the present invention. Therefore tight winding in both cases occurred, it could not be taken out from the spindle of the winder cheese-shaped package of fibers taken 2kg winding. Further, in Comparative Example 4, the draft was too low, and in Comparative Example 5, the draft was too high, so that U% exceeded the range of the present invention. The variation in elongation was also large. These fibers were subjected to stretch false twisting in the same manner as in Example 1. However, fluff and yarn breakage occurred frequently, and false twisted yarns could not be obtained.

[0094]

Comparative Example 6 A fiber was obtained in the same manner as in Example 1 except that polymerization was performed using a titanium dioxide dispersion prepared without performing centrifugation and filtration. The dispersibility of titanium oxide in the polymer was poor, and the aggregate of titanium oxide having a longest portion length exceeding 5 μm was 31 particles / mg polymer, which was out of the range of the present invention.
The titanium oxide aggregates of the obtained fiber exceeded the range of the present invention, and the dispersion of elongation was large. These fibers were stretched and false-twisted in the same manner as in Example 1.
Thread breakage occurred frequently, and a false twisted yarn could not be obtained.

[0095]

Reference Example 1 A cheese-like package was obtained in the same manner as in Example 1 except that the winding width of the cheese-like package was 400 mm. When false twisting was performed using this cheese-like package in the same manner as in Example 1, only a false twisted yarn having a large fluctuation in tension during false twisting and large crimp unevenness was obtained. A tubular knitted fabric was prepared from the obtained fibers, and the dyeing was evaluated. As a result, periodic uneven dyeing was observed.

[0096]

[Table 1]

[0097]

[Table 2]

[0098]

The polyester fiber of the present invention has a proper orientation and crystallinity and has a small unevenness in physical properties such as elongation.
It is a PTT-POY that can be manufactured in stages. For this reason, it is possible to avoid the occurrence of tightness and bulge, and it is possible to industrially manufacture a cheese-like package having a good winding shape. Further, since unevenness in physical properties such as elongation is small and the fiber hardly changes with time, false twisted yarn can be stably and industrially manufactured for a long period of time even in high-speed draw false twisting.
The polyester fiber of the present invention has a high productivity because the fiber can be obtained in only one stage of the spinning process, can produce the fiber at low cost, and has a large winding amount, so that it can be used for winding or processing. The number of switching steps is small, and the manufacturing operation can proceed efficiently. The false twisted yarn produced by using the PTT fiber of the present invention becomes a false twisted yarn suitable as an extremely excellent stretch material having a soft feel, a high crimp rate, and a stretch rate. For this reason, it is useful for so-called zokki or knitting type pantyhose, tights, socks (backing yarn, rubber cuff), jersey, covering yarn of elastic yarn, and companion yarn of knitting products such as knitting pantyhose.

[Brief description of the drawings]

FIG. 1 is an uneven curve (mass change of fiber) when the fiber is passed through USTER TESTER3.

FIG. 2A is a wide-angle X-ray diffraction chart in which peaks derived from crystallinity are observed. Fig. 2- (b)
Is a wide-angle X-ray diffraction chart in which no peak derived from crystallinity is observed.

FIG. 3 is a schematic view showing a cheese-like package in which the polyester fiber of the present invention is wound around a yarn tube. Figure 3-
(A) is a schematic diagram of a desirable cheese-like package. FIG. 3B is a schematic view of a cheese-like package having a bulge.

FIG. 4 is a schematic view showing an outline of a spinning machine for carrying out the present invention.

FIG. 5 is a schematic view showing a schematic view of a zone for heat-treating fibers of a spinning machine embodying the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dryer 2 Extruder 3 Bend 4 Spin head 5 Spinner pack 6 Spinneret 7 Heat insulation area 8 Solid multifilament 9 Cooling air 10 Finishing agent applying device 11 1st roll 12 Free roll 13 Winding machine 13a Spindle, package 13b Touch Roll 14 Spinning chamber 15 Zone for heat treatment of fiber 16 Second roll 17 First Nelson roll 18 Second Nelson roll 19 First heater 20 Second heater

Continued on the front page F term (reference) 4L035 BB33 BB40 CC02 CC13 EE01 EE02 EE20 FF08 HH05 JJ05 KK01 KK05 4L036 MA05 MA26 PA07 PA14 PA26 RA04 UA21

Claims (12)

[Claims] 1. A polyester fiber comprising 90% by mole or more of polytrimethylene terephthalate composed of trimethylene terephthalate repeating units and satisfying the following requirements (A) to (G). (A) Density: 1.320 to 1.340 g / cm ³ (B) Birefringence: 0.030 to 0.070 (C) Peak value of thermal stress: 0.01 to 0.12 cN / dtex (D) Boiling water shrinkage: 3 to 40% (E) Elongation at break: 40 to 140% (F) 0.01 to 3% by weight of titanium oxide having an average particle size of 0.01 to 2 μm is contained, and titanium oxide particles are collected Agglomerates whose maximum length exceeds 5 μm are 12 / mg fiber or less. (G) U%: 0-2% 2. The polyester fiber according to claim 1, wherein the wide-angle X-ray diffraction intensity in a direction perpendicular to the fiber axis satisfies the following expression. I ₁ / I ₂ ≧ 1.0 where I ₁ : 2θ = 15.5-16.5 ° maximum diffraction intensity I ₂ : 2θ = 18-19 ° average diffraction intensity 3. The polyester fiber according to claim 1, wherein the standard deviation of the elongation at break is 0 to 10%. 4. A cheese-like package, wherein the polyester fiber according to claim 1 is wound and has a bulge ratio of 20% or less. 5. The cheese-like package according to claim 4, wherein the wound width of the wound fiber on the yarn tube is 50 to 300 mm, and the weight is 2 kg or more. 6. A false twisted yarn comprising 90% by mole or more of polytrimethylene terephthalate composed of trimethylene terephthalate repeating units and satisfying the following requirements (H) to (K). (H) Stretch elongation rate: 150 to 300% (I) Number of crimps: 4 to 30 pieces / cm (J) Number of snares: 0 to 3 pieces / cm (K) Titanium oxide having an average particle size of 0.01 to 2 μm 0.0
Aggregates containing 1 to 3% by weight of titanium oxide particles and having a maximum length of more than 5 μm are not more than 12 aggregates / mg fiber. 7. The false twisted yarn according to claim 6, wherein the number of crimps is 8 to 25 yarns / cm. 8. An aliphatic ester having a molecular weight of 300 to 800 and / or a redwood viscosity at 30 ° C. of 20 to 1
The false twisted yarn according to claim 6 or 7, wherein the oil agent containing 70 to 100% by weight of the mineral oil for 00 seconds adheres to the false twisted yarn in an amount of 0.5 to 5% by weight. 9. A method for melt-spinning polytrimethylene terephthalate in which at least 90 mol% is composed of trimethylene terephthalate repeating units, wherein a draft satisfying the following requirement (L) is used for the draft during spinning. 6
The molten multifilament extruded from the spinneret to be 0 to 2000 is rapidly cooled to be changed to a solid multifilament, and heat-treated at 50 to 170 ° C.
2000 to 40 at a winding tension of 0.20 cN / dtex
A method for producing a polyester fiber, comprising winding at a speed of 00 m / min. (L) titanium oxide having an average particle size of 0.01 to 2 μm is added to 0.0
Aggregates containing 1 to 3% by weight and aggregated with titanium oxide particles, and the maximum length of the aggregates exceeding 5 μm is 25 / mg polymer or less. 10. A method for producing false twisted yarn, comprising using the polyester fiber according to claim 1. 11. A method for producing a false twisted yarn, comprising untwisting the polyester fiber wound around the cheese-like package according to claim 4 and then performing false twisting. 12. The method for producing a false twisted yarn according to claim 10, wherein a false type false twisting machine is used.