JP3167677B2 - Polyester irregular cross section fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified polyester fiber having a soft and excellent stretchability, and more particularly to a silk-like fiber having a high breaking strength, a yield point strength, and an appropriate irregularity. Material for clothing with high gloss, less trouble such as cutting and fluffing in post-processing process, and less occurrence of fluffing when wearing and remaining "shape" in the part where force was applied. In particular, the present invention relates to a high-grade polyester cross-section fiber suitable for a material for the inner field.

[0002]

2. Description of the Related Art Fibers obtained from polytrimethylene terephthalate obtained by polycondensing a lower alcohol ester of terephthalic acid represented by terephthalic acid or dimethyl terephthalate with trimethylene glycol have excellent elastic recovery and low elasticity. An image that has properties similar to nylon fibers, such as elastic modulus (soft feel) and easy dyeability, and properties similar to polyethylene terephthalate fibers, such as light resistance, heat setting, dimensional stability, low moisture absorption, and yellowing resistance. Utilizing its features, it is applied to BCF carpets, brushes, tennis gut, etc. (Japanese Patent Application Laid-Open Nos. 9-3724 and 8-173244,
JP-A-5-262882 and the like.

[0003] It is also conceivable to develop polytrimethylene terephthalate fibers for use in clothing. In the field of inner applications represented by women's foundations, silky and glossy fabrics having a soft feel and a stretch property are desired. In order to achieve gloss, the fiber must have an irregular cross section such as a cross section. Since the modified cross-section fiber has a higher bending elastic modulus than the round cross-section, when a conventional polyethylene terephthalate modified cross-section fiber is used, only a hard fabric having a rough texture can be obtained. In order to soften the feel, the yarn diameter can be reduced as in the case of ultrafine yarn. However, in this case, the breaking strength of the fiber decreases, and a satisfactory material cannot be obtained as an inner material. On the other hand, nylon fibers have a soft texture, but they may turn yellow due to sweat or the like while being worn.

When the polytrimethylene terephthalate fiber is used, the garment can be made to have a good touch due to its soft feeling, stretchability and dimensional stability. In addition, since dyeing can be performed at 110 ° C. or less, dyeing can be performed without damaging fibers mixed with fibers susceptible to thermal degradation at a dyeing temperature exceeding 110 ° C. such as wool, silk, polyurethane fiber, and acetate fiber. It has excellent processing characteristics. However, in the case of a modified cross-section fiber, the breaking strength is lower than that of a round cross-section, and a polytrimethylene terephthalate fiber having a lower breaking strength than a polyethylene terephthalate fiber or a nylon fiber can obtain only a modified cross-section fiber having a lower breaking strength. However, the strength of the obtained fabric is insufficient.

[0005] Further, since the yield point strength is low, the shape of the worn portion remains when the inner or the like is worn.
Such problems are also likely to occur. Further, polytrimethylene terephthalate polymer has a high crystallization rate, so that uneven cooling is likely to occur, and the U%, which is the yarn diameter unevenness, becomes large, and the "slack", which is a phenomenon that the yarn length becomes uneven, occurs. I will. This sagging becomes more severe when a high degree of drawing orientation is used to increase the yarn strength. Clothing fibers using a polytrimethylene terephthalate polymer are disclosed in JP-A-52-5320.
However, this publication does not disclose extrusion or cooling of a polymer except for using an undrawn yarn obtained without asymmetric cooling, and obtains a deformed fiber having a high breaking strength and a high yield point strength and a good quality. It is not possible.

JP-A-52-8123, JP-A-52-8124, and JP-A-58-104216 disclose extrusion temperature, draft, Δn of undrawn yarn, and the like during spinning. However, even here, no specific content regarding spinning is described, so that even if the conditions of the polyethylene terephthalate modified cross-section yarn are applied, a fiber of satisfactory quality cannot be obtained. Further, from the viewpoint of the breaking strength of the round cross-section fiber, it is not possible to obtain a polytrimethylene terephthalate modified cross-section fiber having a high breaking strength and a yield point strength required for inner use. JP-A-9-262046 discloses a high-strength polytrimethylene terephthalate fiber. Here, a high-density fiber having a high denier is obtained by performing two-step stretching in a hot water bath and dry heat using a polymer having a high degree of polymerization. However, this method is a technique relating to a fiber having a single yarn of 10 to 100 denier, and cannot be applied to a fiber having a small single yarn denier as it is for clothing, and a modified cross-section fiber for clothing of good quality is used. You can't get it.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of the conventional modified cross-section fibers, and is soft, has excellent stretchability, and has a high breaking strength, a yield point strength, and an appropriate degree of irregularity. It has a silky luster and has few troubles such as cutting and fluffing in the post-processing process, and it is hard to cause fluffing when wearing and leaving the shape of the part where the force is applied, "mold removal", etc. The present invention provides a high-grade polyester modified cross-section fiber suitable for a material for use in the field of innerwear, particularly a material for the inner field.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned drawbacks, and as a result, have found the possibility of solving the above-mentioned conventional problems. As a result of further studies, they have reached the present invention. Was. That is, a first aspect of the present invention is a fiber substantially composed of polytrimethylene terephthalate, which has a breaking strength of 4 g / d or more and a yield point strength of 2.5 g / d.
d or more, the elongation at break is 15 to 50%, the unevenness of elongation at break of the fiber represented by the following formula (1) is 1 to 1.2, and the irregularity of the fiber cross section represented by the following formula (2) is 1.1. It is a polyester modified cross-section yarn characterized by having a molecular weight of ~ 1.8. Uneven breaking elongation = maximum breaking elongation of single yarn / minimum breaking elongation of single yarn Formula (1) Deformity = (circumscribed circle diameter) / (inscribed circle diameter) formula (2) Diameter of circumscribed circle: diameter of the smallest circle surrounding the entire fiber cross section Diameter of inscribed circle: diameter of the largest circle entering the fiber cross section

A second aspect of the present invention is that when melt-spinning a polyester polymer substantially composed of polytrimethylene terephthalate, the intrinsic viscosity [η] is 0.5 to 1.
5, the extrusion temperature is 250-290 ° C.,
Extrusion from a spinning machine with a spinneret surface temperature of 235 to 275 ° C,
After cooling and solidifying without partial cooling, 2000-5000 m /
This is a method for producing a polyester irregular cross-section fiber, characterized in that the yarn wound in a minimum is drawn at a drawing temperature of 20 to 70 ° C. at a draw ratio of 70 to 99% of the maximum draw ratio. The polymer substantially composed of polytrimethylene terephthalate used in the present invention, using terephthalic acid as an acidic component,
It is necessary to be composed of a polyester polymer containing trimethylene glycol as a glycol component in an amount of 80 mol% or more.

In the present invention, the trimethylene glycol is selected from 1,3-propanediol, 1,2-propanediol, 1,1-propanediol, 2,2-propanediol, and a mixture thereof. However, 1,3-propanediol is particularly preferred from the viewpoint of stability. The content of trimethylene glycol is preferably at least 80 mol% of the glycol component.
If the amount is less than 80 mol%, not only the stretchability and softness, which are the objects of the present invention, cannot be achieved, but also the ease of dyeing and the like will be reduced, and the objects of the present invention will not be achieved. Preferably 90
Mol% or more. Further, by setting the ratio of trimethylene glycol to 80 mol% or more, the gloss of the modified cross-section fiber is improved. This is probably because the refractive index increases.

In the polytrimethylene terephthalate used in the present invention, if necessary, isophthalic acid, succinic acid, adipic acid, 2,6-naphthalenedicarboxylic acid, etc. may be used as long as the effects of the present invention are not impaired. A glycol component such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, or polyoxyalkylene glycol may be copolymerized as the glycol component. If necessary, various additives such as a matting agent, a heat stabilizer, a flame retardant, an antistatic agent, and an antifoaming agent may be copolymerized or mixed. The polymer used in the present invention can be polymerized by a known polyester polymerization method.

In order to obtain a high-strength, high-gloss and soft-texture fabric suitable for applications such as women's foundations, which is the object of the present invention, the fiber breaking strength and the yield point strength are high. It is necessary to have a predetermined elongation at break and an elongation at break and unevenness of elongation at break. The breaking strength of the fiber must be 4 g / d or more, preferably 4.5 g / d or more, more preferably 5 g / d or more, depending on the application. If the breaking strength is less than 4 g / d, the obtained fabric will be very easily torn.

It is also important that the deformed fiber of the present invention has a high yield point strength. The yield point strength of the fiber needs to be 2.5 g / d or more, preferably 3 g / d or more, and more preferably 3.5 g / d or more. When the yield point strength of the fiber is less than 2.5 g / d, when a product such as an inner or the like is actually worn, a phenomenon that a so-called "mold release" occurs due to partial application of a force to form a mold. Will occur. The yield point strength is the strength at which the elastic modulus suddenly changes when a tensile test is performed on the fiber, and the fiber almost returns to its original length as long as the fiber is pulled with a force less than this strength. The detailed method of measuring the yield point strength will be described in the embodiments of the invention. As the degree of polymerization of such a fiber, the intrinsic viscosity [η] is preferably from 0.5 to 1.2. If it is less than 0.5, sufficient strength may not be obtained. Moreover, it is difficult to stably spin fibers of 1.2 or more.

In order to increase the yield point strength, it is necessary to use the polymer of the present invention, and it is preferable to increase the degree of crystallinity and the degree of orientation of molecules in the fiber axis direction. By increasing the degree of crystallinity and the degree of orientation, it is possible to increase the yield point elongation, which is the area where the deformed fiber returns to the original shape, and the stress at that time (yield point stress). It is less likely that "mold removal" in which the mold of the portion where the force is applied remains. Therefore, in the fiber of the present invention, the density as an index of the crystallinity is 1.3 to 1.45 g / cm ^3.
It is desirable that The higher the density, the higher the crystallinity. If the density is less than 1.3 g / cm ³ , the crystallinity of the fiber is low, and only a fiber that is easily deformed can be obtained. Since the crystal density of the polymer of the present invention is 1.45 g / cm ³ or less, the fiber density does not substantially exceed 1.45 g / cm ³ . The density of the fibers is preferably between 1.35 and 1.4.
g / cm ³ .

The elongation at break of the fiber needs to be 15 to 50%, preferably 18 to 40%. If the elongation at break is less than 15%, a large number of fluffs and the like are generated, and not only cannot it be manufactured stably, but also it is easy to break during post-processing, resulting in fibers that are very difficult to handle. Although the elongation at break may be high, it is necessary to be 50% or less in order to satisfy the above breaking strength and yield strength. Further, it is necessary that the breaking elongation unevenness of the fiber represented by the following formula (1) is 1 to 1.2. Uneven breaking elongation = maximum breaking elongation of single yarn / minimum breaking elongation of single yarn Equation (1)

Here, the maximum and minimum breaking elongation of the single yarn represent the elongation of the single yarn that is cut last and the single yarn that is cut first when the fiber is subjected to a tensile test, respectively. If the elongation at break exceeds 1.2, the fiber contains a single yarn that is easily stretched, and this is a phenomenon in which the length of the single yarn is different due to stretching during the production or post-processing of the fiber. Will occur. When all elongations are the same, the elongation at break is 1 and there is no value less than this. Unevenness in breaking elongation is preferably 1 to 1.1 to prevent sagging.
5

The cross-sectional shape of the fiber for producing a glossy fiber suitable for the present invention may be any one of an ellipse other than a circle, a polygon such as a triangle and a square, a star, an L-shape and the like.
Considering the strength, a triangle or a square is preferable. Of course, since it is a fiber of a molten polymer, the corners of a triangle or a square may be round rather than acute. In order to obtain glossy fibers, it is necessary that the irregularity of the fiber cross section represented by the following formula (2) is 1.1 to 1.8 in these cross sections. Degree of irregularity = (circumscribed circle diameter) / (inscribed circle diameter) Equation (2) Diameter of circumscribed circle: diameter of the smallest circle surrounding the entire fiber cross section Inscribed circle diameter: most enclosed in fiber cross section Large circle diameter

When the degree of irregularity is less than 1.1, the cross section of the fiber is close to a circle, and does not become the glossy fiber of the present invention. On the other hand, when the degree of irregularity exceeds 1.8, uneven orientation and crystallization are formed inside the single yarn, and not only spinning cannot be performed stably, but also the breaking strength of the fiber is greatly reduced. The degree of irregularity is preferably in the range of 1.2 to 1.7, and more preferably in the range of 1.3 to 1.6.

The fineness of the modified cross-section fiber of the present invention is preferably such that the single yarn fineness is 0.1 to 10 denier. In the case of fibers with a modified cross section having a fineness of less than 0.1 denier, it is difficult to set the breaking strength and the degree of irregularity in the range of the present invention. On the other hand, if the fineness exceeds 10 denier, the flexural modulus increases even if the degree of irregularity is reduced, and the fabric obtained from this fiber becomes stiff and difficult to have a soft feel. The single yarn fineness is preferably in the range of 0.2 to 5 denier, and more preferably in the range of 0.5 to 3 denier.

The number of single yarns of the modified cross-section fiber of the present invention is not particularly limited.
The number is 2,000, preferably 5 to 500, and more preferably 10 to 200. If the number of single yarns is less than 3, the total fineness becomes too small, and handling during post-processing becomes extremely difficult. On the other hand, if the number of single yarns exceeds 2,000, the total denier of the fibers becomes too large, so that the fibers do not have a texture suitable for clothing. In addition, the spinning becomes very large, and it is necessary to use a device with poor workability.

Next, a preferable method for producing the polyester cross-section fiber of the present invention will be described. That is, in the second aspect of the present invention, when melt-spinning a polyester polymer substantially composed of polytrimethylene terephthalate, a polymer having an intrinsic viscosity [η] of 0.5 to 1.5 and an extrusion temperature of 250 to 250 are used. ~ 290 ° C, spinning surface temperature is 2
After being extruded from a spinning machine at 35 to 275 ° C. and solidified by cooling without uneven cooling, a yarn wound at 2000 to 5000 m / min was drawn at a stretching temperature of 20 to 70 ° C. and a maximum draw ratio of 70%.
A process for producing a polyester cross-section fiber, characterized in that the fiber is drawn by up to 99%.

In order to increase the breaking strength and the yield point strength of the polytrimethylene terephthalate fiber, a polymer having a high degree of polymerization is used. It is important to stretch the oriented undrawn yarn. On the other hand, in order to have a proper degree of irregularity, it is important to extrude a molten polymer having a proper viscosity from a spinneret having a relatively low temperature. Therefore, in the production method of the present invention, the intrinsic viscosity [η] of polytrimethylene terephthalate is 0.5 to 0.5.
It needs to be 1.5. The intrinsic viscosity [η] is 1.
If it exceeds 5, no matter how high the spinning temperature is, the melt viscosity becomes high and extrusion with a normal spinning machine becomes difficult. When the intrinsic viscosity [η] is less than 0.5, the mechanical properties such as the breaking strength of the fiber having a modified cross section are reduced, and only a fiber which can be easily removed from the mold is obtained. A preferred intrinsic viscosity [η] is 0.6 to 1.2, and more preferably 0.65 to 1.
0.

The extrusion temperature during melt spinning is from 250 ° C. to 2 ° C.
90 ° C, preferably 255 ° C to 285 ° C, more preferably 260 ° C to 280 ° C. If the temperature is less than 250 ° C., the melt viscosity becomes high and extrusion becomes difficult, and the obtained fiber has unsatisfactory non-uniform breaking elongation and U%. Further, at 290 ° C. or higher, the degree of polymerization is reduced due to severe decomposition of the polymer, the breaking strength and the yield point strength are low, and only colored fibers can be obtained, and the polymer viscosity immediately below the spinning nozzle is significantly reduced. It becomes difficult to obtain fibers having a high degree of irregularity.

In the present invention, it is very important that the spinning surface temperature at the time of extruding the polymer is 235 to 275 ° C. If the spinning surface temperature is lower than 235 ° C., the polymer is not extruded in a completely melted state, resulting in a fiber having large breaking elongation unevenness and large U% unevenness. On the other hand, at 275 ° C. or higher, it is not possible to obtain a fiber having the irregularity of the present invention.
The surface temperature of the spout is preferably 240 to 270 ° C, and 245 to 270 ° C.
265 ° C. is more preferred.

The extruded molten polymer is cooled and solidified. At this time, it is necessary that the partial cooling is not performed. The uneven cooling causes a difference in the molecular orientation between the single yarns, so that the unstretched non-uniform breaking elongation occurs, and the stretched fiber also has the non-uniform breaking elongation, which causes slackness. Preferably, the fibers do not cool too quickly. The shape of the spout is not particularly limited, but when manufacturing fibers having a triangular cross-section, use a spout having a Y-shaped discharge hole when manufacturing fibers having a square cross-section. Is preferred. The fiber bundle discharged from the spinneret and cooled and solidified is taken out, wound up as an undrawn yarn, and drawn by a known method.
At the time of collection, the fiber bundles are bundled, and a known lubrication or pre-entanglement is applied.

The winding speed of the undrawn yarn is from 2000 to 5
000 m / min. Particularly preferably, it is 2500-4000 m / min from the viewpoint of strength development. If the spinning speed exceeds 5000 m / min, crystallization proceeds excessively in the spinning process, making it difficult to perform sufficient orientation in subsequent drawing, and increasing the yarn diameter unevenness.
Further, when the spinning speed is less than 2000 m / min, the degree of orientation of the undrawn yarn does not become so high that it becomes difficult to sufficiently orient the molecules in the subsequent drawing, and the object of the present invention is to achieve the breaking strength and the yield point strength. However, it becomes difficult to obtain a modified cross section fiber having a high cross section.

In the stretching of the modified polyester fiber of the present invention, the undrawn fiber may be drawn after being wound once, or may be drawn continuously between two or more godet rolls without being wound once. . When the undrawn fiber is once wound and drawn, it is preferable that the drawing be performed for 12 to 96 hours after the winding. Since the undrawn fiber is amorphous, structural changes such as crystallization and orientation relaxation occur even at room temperature, and the maximum draw ratio changes, and accordingly, the physical properties of the drawn fiber also change. In particular, if the time is less than 12 hours after the winding, the structural change is large, and even if the drawing is performed under the same conditions, the fiber properties are greatly changed. On the other hand, if it exceeds 96 hours, crystallization and orientation relaxation progress, and it is difficult to continuously perform high-magnification stretching to obtain a fiber having high breaking strength and high yield point strength, which is the object of the present invention. Would.

The fibers are preferably drawn between 24 and 72 hours after spinning. The unstretched fiber has a temperature of 0 to 30 ° C and a humidity of 20 to 80% RH in order to avoid a structural change.
Below, it is preferable to store in an atmosphere of preferably 10 to 25 ° C. and 40 to 60% RH or less. The structural change of the unstretched fiber exceeds 30 ° C. and becomes intense when the humidity exceeds 80% RH, which is not preferable. When the temperature is lower than 0 ° C., the finishing agent of the applied fiber freezes. It is not preferable because moisture in the finish evaporates.
The draw ratio varies depending on the degree of polymerization of the undrawn yarn, the winding speed, the cooling temperature, and the yarn type, but it is necessary to draw at 70 to 99% of the breaking draw ratio, and preferably 80 to 97%. 7
If it is 0% or less, a fiber having high breaking strength and high yield point strength cannot be obtained. On the other hand, if the magnification exceeds 99%, yarn breakage occurs frequently, and the fiber cannot be drawn stably.

The stretching temperature must be 20 ° C. to 70 ° C., preferably 25 ° C. to 65 ° C., and more preferably 30 ° C. to 60 ° C. If the stretching temperature is lower than 20 ° C., not only continuous yarn cannot be drawn due to frequent thread breakage during stretching,
The obtained fiber is sagged due to uneven drawing, and fine cracks are generated inside the fiber, resulting in a white and glossy fiber, and a reduced breaking strength. If the stretching temperature exceeds 70 ° C., slipperiness with a stretching roll or the like is deteriorated, single yarn breakage occurs frequently, and stable stretching becomes difficult, and since the orientation of molecules is relaxed, the breaking strength of the fiber also decreases. I will. Regarding how to apply the temperature at the time of stretching, a heated roll or a heated pin may be used, or a non-contact type heater may be used. It is desirable to use a heating roll in order to suppress the slack which reduces the stretching unevenness.

It is desirable that the drawn yarn is heat-treated at 90 to 200 ° C, preferably 100 to 190 ° C.
If the heat treatment temperature is less than 90 ° C., the crystallinity of the fiber cannot be sufficiently increased, and it becomes difficult to obtain a fiber having high breaking strength and yield strength. Heat treatment temperature is 200
Above ° C, fiber breakage is likely to occur, making continuous heat treatment difficult.

The polytrimethylene terephthalate modified cross-section fiber fiber of the present invention can be used as a fabric alone or as a mixture with other fibers. As other fibers to be mixed, any of polyester, polyamide, cellulose, wool, cotton, silk, acetate, stretch fiber, and the like, or a mixture thereof may be used. Examples of the mixing method include a woven fabric used for warp or weft, a woven fabric such as a reversible woven fabric, and a knitted fabric such as tricot and Russell. In addition, twisting, twining, and entanglement may be performed. In particular, since the polytrimethylene terephthalate modified cross-section fiber of the present invention can be dyed at 110 ° C. or lower, it is difficult to mix with fibers susceptible to thermal degradation at a dyeing temperature exceeding 110 ° C. such as wool, silk, polyurethane fiber, and acetate fiber. It is suitable because it can be dyed without damaging them.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to examples and the like, but the present invention is not limited to the examples and the like. In addition, the main measurement value in an Example was measured by the following method. (1) Intrinsic viscosity [η] Intrinsic viscosity [η] is a value obtained based on the following definition formula. Ηr in the definition formula is a value obtained by dividing the viscosity at 35 ° C. of a diluted solution of polytrimethylene terephthalate dissolved in o-chlorophenol having a purity of 98% or more by the viscosity of the solvent itself measured at the same temperature, It is defined as relative viscosity. C is the solute weight value in grams in 100 ml of the solution.

(2) Density Measurement was performed using a density gradient tube made of carbon tetrachloride and toluene. (3) Breaking strength, breaking elongation, uneven breaking elongation Using Orientec Co., Ltd. Tensilon, yarn length 20c
m, and a tensile test was performed under the conditions of a tensile speed of 20 cm / min. The breaking elongation unevenness is the elongation of the single yarn that broke first during the tensile test (minimum breaking elongation).
And the elongation (maximum elongation at break) of the single yarn that was most recently broken was calculated by the following equation. Uneven breaking elongation = (minimum breaking elongation) / (maximum breaking elongation)

(4) Yield point strength Yield point strength was measured by conducting a tensile test using the same apparatus and conditions as those for breaking strength. Figure 1 shows the results of the tensile test.
An SS curve showing the relationship between elongation and stress as shown in FIG. When the elongation is small, the stress increases substantially along the line AA '. When the elongation is further increased, the rate of increase of the stress decreases sharply from the point B. The yield point strength was determined from the stress at point B that deviated from AA 'using the following equation. Yield point strength (g / d) = stress at point B (g) / denier of fiber (d)

(5) Deformity Degree was calculated from the cross-sectional photograph of the fiber by the following equation (2). Degree of irregularity = (circumscribed circle diameter) / (inscribed circle diameter) Equation (2): circumscribed circle diameter: diameter of the smallest circle surrounding the entire fiber cross section inscribed circle diameter: most inside the fiber cross section Large circle diameter

(6) U% USTE manufactured by Zellweger Uster Co., Ltd.
The measurement was performed using R TESTER3. Measurement is 20
The measurement was performed at a speed of 0 m / min, and an average value for 5 minutes was used. (7) Sag The deformed cross-section fiber obtained by spinning-drawing was pulled out from the bobbin with a length of 1 m, and the presence or absence of the slack was visually judged under a tension of (1/20 × fineness) g. . The case where no slack was observed in the fiber was evaluated as ○, the case where slight sag was observed was evaluated as Δ, and the case where a large amount of sag was observed was evaluated as ×.

(8) Dyeability: exhaustion rate, deep chromaticity (K /
S)｝ The sample was a single-knit knitted fabric, and two score rolls 400 were used.
A scouring treatment was performed at 70 ° C. for 20 minutes using warm water containing g / liter, dried by a tumbler drier, and then heat-set at 180 ° C. for 30 seconds using a pin tenter. The exhaustion rate was evaluated based on the exhaustion rate after the temperature was raised from 40 ° C. to 110 ° C. and further kept for 1 hour. The dye used was Kayaron Polyester Blue 3RSF (manufactured by Nippon Kayaku Co., Ltd.), 6% owf, bath ratio 1:50.
Stained. As a dispersant, 0.5 g / l of Nikka San Salt 7000 (manufactured by Nika Chemical Co., Ltd.) was used, and 0.25 ml / l of acetic acid and 1 g / l of sodium acetate were added to adjust the pH to 5.

The deep chromaticity, which indicates how deep the color was, was evaluated using K / S. This value is obtained by measuring the spectral reflectance R of the sample cloth after dyeing, and
It was determined from the equation of Kubelka-Munk.
The larger this value, the greater the deep color effect, ie,
Indicates that the color is well developed. As R, the value at the maximum absorption wavelength of the dye was used. K / S = (1-R) ² / 2R

[0039]

Example 1 1,3-propanediol and dimethyl terephthalate are polycondensed by a conventional method, and the intrinsic viscosity [η] is obtained.
A polytrimethylene terephthalate polymer of 0.9 was obtained. This polytrimethylene terephthalate polymer was extruded at an extrusion temperature of 260 ° C. at a discharge rate of 23.1 g / min using a spinneret in which 36 Y-shaped holes were arranged in a single circle. In the spinneret, the periphery other than the discharge surface was shielded by a heat insulating plate having a thickness of 16 mm. The spinning surface temperature at this time was 255 ° C. Cooling is performed at a wind speed of 0.4 m / sec.
It was applied to the fiber from 0 mm. The cooled unshaped cross-sectioned fibers are bundled into a bundle by a bundle guide,
It was wound at 00 m / min. The spinning was extremely stable without breakage for 24 hours.

The obtained undrawn yarn was subjected to a temperature of 20 ° C. and a humidity of 5
After storing in a storage place adjusted to 5% for 24 hours, a hot roll at 55 ° C., a hot plate at 140 ° C., a draw ratio of 1.8 times (95% of the maximum draw ratio), and a drawing speed of 800 m
The fiber was drawn at a rate of 50.5 denier / 36 filaments. The modified cross-section fiber has an intrinsic viscosity [η] of 0.68, a degree of irregularity of 1.45, and a breaking strength of 5.2 g /
d, elongation at break of 22% and yield point strength of 4.1 g / d, showing good tensile properties. The elongation at break of the fiber is 1.1,
U% was as good as 1.2%, and no slack was observed in the fiber. At this time, the fiber density was 1.355 g / cm ^3, and the fiber had high crystallinity. When this irregular cross-section fiber was knitted in a tube, the obtained knitted tube had a silky luster and a very soft feel.

The dye exhaustion at 100 ° C. of the modified cross-section fiber of this example was 88%, and the K / S was 21.3. This result shows that when a multifilament made of polyethylene terephthalate having the same single fiber fineness is dyed at 130 ° C. for 60 minutes, the dye exhaustion rate is 91% and the K / S is 21, so that it is extremely easy to dye and has high coloring properties. Is good.

[0042]

Examples 2 to 6, Comparative Examples 1 to 5 Spinning conditions (winding speed,
Stretching ratio, heat treatment temperature) as shown in Table 1,
In the same manner as in Example 1, a fiber having a modified cross section was obtained. The results are shown in Tables 1 and 2. The modified cross-section fibers within the scope of the present invention had good gloss, strength, and softness. On the other hand, fibers having irregular cross-sections (Comparative Examples 1 to 5) out of the range of the present invention could not obtain satisfactory gloss and strength.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

Comparative Example 6 Polymerization, spinning and stretching were carried out in the same manner as in Example 1 except that the temperature of the hot roll was changed to 15 ° C. During drawing, yarn breakage frequently occurred, and fibers could not be obtained continuously. In addition, many slacks were observed in the obtained fiber.

Comparative Example 7 Polymerization, spinning and stretching were carried out in the same manner as in Example 1 except that the temperature of the hot roll was changed to 85 ° C. Since the yarn was fused to the hot roll during stretching, single yarn breakage occurred frequently, and the resulting fiber was full of fluff.

[0046]

Comparative Example 8 Polymerization, spinning and stretching were carried out in the same manner as in Example 1 except that the temperature of the hot plate was 210 ° C. The fibers broke at the hot plate and could not be stretched.

COMPARATIVE EXAMPLE 9 Ethylene glycol and dimethyl terephthalate were polycondensed by a conventional method to obtain a polyethylene terephthalate polymer having an intrinsic viscosity [η] of 0.7. Using this polymer, spinning and stretching were carried out in the same manner as in Example 1 to obtain fibers with irregular cross sections. However, this fiber has a high elastic modulus,
Only a stiff, hard-textured fabric could be obtained.

[0047]

The polyester modified cross-section fiber composed of polytrimethylene terephthalate obtained by the present invention improves the drawbacks of conventional fibers, is soft and has excellent stretchability, and has high breaking strength, yield strength, and moderate Due to its irregular shape, it has silk-like luster, and there are few troubles such as cutting and fluffing in the post-processing process, and there is little fluffing when worn, materials for clothing, especially materials for the inner field Useful for

[Brief description of the drawings]

FIG. 1 is an SS curve showing the relationship between elongation and stress when a tensile test is performed.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D01F 6/62

Claims (2)

(57) [Claims] 1. A fiber substantially composed of polytrimethylene terephthalate, having a breaking strength of 4 g / d or more, a yield point strength of 2.5 g / d or more, and a breaking elongation of 15 to 15 g / d.
50%, and the irregularity of elongation at break of the fiber represented by the following formula (1) is 1 to 1.2, and the irregularity of the fiber cross section represented by the following formula (2) is 1.1 to 1.8. Characterized polyester modified cross section fiber. Uneven breaking elongation = maximum breaking elongation of single yarn / minimum breaking elongation of single yarn Formula (1) Deformity = (circumscribed circle diameter) / (inscribed circle diameter) formula (2) Diameter of circumscribed circle: diameter of the smallest circle surrounding the entire fiber cross section Diameter of inscribed circle: diameter of the largest circle entering the fiber cross section 2. When melt-spinning a polyester polymer substantially composed of polytrimethylene terephthalate, a polymer having an intrinsic viscosity [η] of 0.5 to 1.5, an extrusion temperature of 250 to 290 ° C., After being extruded from a spinning machine having a spinneret surface temperature of 235 to 275 ° C. and solidified by cooling without uneven cooling, the yarn wound at 2000 to 5000 m / min was drawn at a stretching temperature of 20 to 70 ° C. and a maximum draw ratio of 7
A method for producing a polyester cross-section fiber, wherein the fiber is stretched by 0 to 99%.