JP2006274501A - Splittable conjugate fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide easily splittable conjugate fiber having such physical properties as to be suitable for enabling presenting high-density woven fabrics excellent in windbreaking tendency, softness and dyeability. <P>SOLUTION: The splittable conjugate fiber is composed of a polylactic acid-based and easily degradable polyester A and a polytrimethylene terephthalate-based polyester B, wherein the polyester A occupies at least part of the fiber surface. The conjugate fiber is characterized by having a fiber shrinkage of 9-20%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a split type composite fiber having suitable fiber properties that can provide a high-density fabric excellent in windproof property, softness, and dyeability, and that can be easily split.

  A method for obtaining ultrafine fibers by reducing the weight of split-type composite fibers composed of a plurality of components is widely known. However, most of them are composite fibers using polyethylene terephthalate (hereinafter referred to as PET) polymer, and ultrafine fibers obtained by reducing the amount of the composite fibers need to be dyed at a high temperature of 100 ° C. or higher. Color development was not obtained, and there was a restriction on product development in dark colors. Further, since the Young's modulus of PET itself is high, the softness is insufficient, and there is a drawback that the texture is hard when a high-density fabric is formed.

  In contrast, polytrimethylene terephthalate (hereinafter referred to as 3GT) obtained by polycondensation of lower alkyl ester of terephthalic acid represented by terephthalic acid or dimethyl terephthalate and trimethylene glycol (1,3-propanediol). ) Has attracted attention in recent years because it has characteristics such as a low Young's modulus and easy dyeability compared to PET and polybutylene terephthalate (hereinafter referred to as PBT).

  Regarding the ultrafine fiber of 3GT, a technology for reducing the amount of alkali of 5-sodium sulfoisophthalic acid copolymerized PET and 3GT sea-island composite fiber has been disclosed (see Patent Document 1). Melting point is higher than 3GT. Since 3GT is a polymer with low heat resistance and easily decomposes under temperature conditions above the melting point, only composite fibers with low strength can be obtained when co-spun with copolymerized PET as in Patent Document 1, At the same time, the fiber shrinkage also decreases, so that it is impossible to obtain a fabric having a high windproof property as intended by the present invention. Furthermore, it was revealed that yarn breakage frequently occurred in terms of the yarn forming property, and the productivity was inferior.

On the other hand, for split type composite fibers using biodegradable polylactic acid (hereinafter referred to as PLA) as a component to be reduced and decomposed, composite fibers of PLA and PET or PLA and isophthalic acid copolymerized PET (patent document) 2) and a composite fiber of PLA and PBT (see Patent Document 3), but the case of using 3GT has not been clarified, and as described above, ultrafine fiber using PET or PBT. However, since the dyeability and softness are insufficient and the fiber shrinkage is low, a fabric having high windproof properties and soft and good dyeability cannot be obtained.
JP 2001-348735 A (Claims) JP-A-11-302926 (Claims) JP-A-8-35121 (Claims)

  The present invention is intended to solve the above-mentioned conventional problems, and has a suitable fiber physical property capable of providing a fabric excellent in windproof property, soft property and dyeability, and can be easily disassembled. It is to provide a composite fiber.

The present invention is achieved by adopting the items described in the following (1) to (4).
(1) A composite fiber composed of easily degradable polyester A mainly composed of polylactic acid and polyester B mainly composed of polytrimethylene terephthalate, and polyester A occupies at least a part of the fiber surface. The split type composite fiber, wherein the fiber shrinkage of the composite fiber is 9 to 20%.
(2) The split type composite fiber according to (1), wherein the peak value of shrinkage stress is 0.20 to 0.50 cN / dtex.
(3) The split type conjugate fiber according to (1) or (2), wherein the initial tensile resistance is 20 to 40 cN / dtex.
(4) A fiber product comprising the split-type conjugate fiber according to any one of (1) to (3).

  According to the present invention, it is possible to provide a polyester split type composite fiber that is excellent in softness and dyeability that could not be achieved by the prior art, and that has high windproof properties when made into a fabric.

  Hereinafter, the present invention will be described in detail.

  First, the split type composite fiber of the present invention will be described. The composite fiber is a split type composite fiber composed of polyester A containing PLA as a main component and polyester B containing 3GT as a main component, and the polyester B is divided into a plurality of segments by the polyester A. FIG. Examples include sea-island type composite fibers and split fiber type composite fibers as shown in FIG. There are no particular restrictions on the number of divisions and the fineness, and it should be set in consideration of the final product and productivity.

  Polyester A, which is one component of the composite fiber, is a polyester mainly composed of PLA and is a component eluted by alkali treatment. By using PLA for polyester A, the spinning temperature can be set low, and thermal degradation of polyester B (3GT) can be minimized. Furthermore, since 3GT and PLA are similar in tension and shrinkage behavior in the spinning process, very good process stability can be obtained during composite spinning. In addition, unlike PET in which a conventional organic metal salt is copolymerized, an acid treatment step is not required for weight reduction, so that it is possible to reduce the environmental load without discharging an acidic solvent. At the same time, the elution process can be shortened, which is preferable.

Here, PLA used in the present invention is a polymer having — (O—CHCH ₃ —CO) n— as a repeating unit, which is obtained by polymerizing lactic acid or its oligomer. Since lactic acid has two types of optical isomers, D-lactic acid and L-lactic acid, the polymer is poly (D-lactic acid) consisting only of D isomer and poly (L-lactic acid) consisting only of L isomer, and There is polylactic acid consisting of both. The optical purity of D-lactic acid or L-lactic acid in polylactic acid is lowered, the crystallinity is lowered, and the melting point drop is increased. Therefore, the optical purity is preferably 90% or more in order to improve heat resistance. A more preferable optical purity is 93% or more, and a still more preferable optical purity is 97% or more. As described above, the optical purity has a strong correlation with the melting point, the optical purity is about 90%, the melting point is about 150 ° C., the optical purity is 93%, the melting point is about 160 ° C., the optical purity is 97%, and the melting point is about 170 ° C. It becomes. In addition to the system in which two types of optical isomers are simply mixed as described above, the two types of optical isomers are blended and formed into a fiber, and then subjected to high-temperature heat treatment at 140 ° C. or higher. A stereo complex in which a racemic crystal is formed is more preferable because the melting point can be dramatically increased.

  The other component, polyester B, is a polymer mainly composed of 3GT, and is a component that constitutes ultrafine fibers after the alkali weight loss treatment. In the present invention, by setting polyester B to 3GT, it is possible to obtain softness and dyeability that could not be obtained with conventional ultrafine fibers of PET or PBT, and to exhibit excellent windproof properties during fabric formation. it can. 3GT used in the present invention is 3GT composed of 90% by mole or more of repeating units of trimethylene terephthalate, and 3GT here refers to terephthalic acid as the main acid component and 1,3-propanediol as the main glycol component. The resulting polyester. However, it may contain a copolymer component capable of forming another ester bond at a ratio of 10 mol% or less. Examples of copolymerizable compounds include dicarboxylic acids such as isophthalic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, and sebacic acid, while glycol components include, for example, ethylene glycol, diethylene glycol, butanediol, neopentyl glycol, and cyclohexanedimethanol. , Polyethylene glycol, polypropylene glycol and the like can be mentioned, but are not limited thereto. Further, titanium dioxide as a matting agent, silica or alumina fine particles as a lubricant, hindered phenol derivatives, coloring pigments and the like as antioxidants can be added as necessary.

  The preferable intrinsic viscosity of 3GT in the present invention is 0.7 to 2.0, and when the intrinsic viscosity is 0.7 or more, it becomes easy to produce a fiber having sufficient strength and elongation. A more preferable intrinsic viscosity is 0.8 or more. Further, when the intrinsic viscosity is 2.0 or less, production stability is easily obtained. A more preferable intrinsic viscosity is 1.5 or less.

  The composite ratio of polyester A and polyester B can be set arbitrarily, but in the range of 1: 9 to 5: 5 in consideration of the splitting property and the product loss due to the weight loss of polyester A (PLA) Is more preferable, and a range of 2: 8 to 4: 6 is more preferable. By making the composite ratio of the polyester A 10% or more, it is possible to avoid a composite abnormality with the polyester B and to shorten the passage time of the pipe after the polyester A is melted. Improvement is possible. Moreover, when the composite ratio of polyester A is 50% or less, the loss of product amount due to weight loss can be reduced.

  On the other hand, in order to obtain excellent splitting properties, it is necessary to dispose polyester A so as to occupy at least a part of the fiber surface. By exposing the polyester A to the fiber surface, the weight reducing agent acts directly on the polyester A, so that it is possible to divide efficiently in a shorter time under milder weight loss conditions than when not exposed. .

  Next, the physical properties of the split composite fiber of the present invention will be described.

  In order to develop an excellent windproof property and softness when the conjugate fiber of the present invention is made into a fabric, the fiber shrinkage ratio needs to be 9 to 20%. By setting the fiber shrinkage within the above range, the tissue density is increased by heat set shrinkage in the high-order processing after forming the fabric, and excellent windproof properties can be obtained. If the fiber shrinkage ratio is less than 9%, sufficient heatproofing cannot be obtained because the heat set shrinkage in high-order processing is low. Conversely, if the fiber shrinkage ratio exceeds 20%, delayed shrinkage during winding of the yarn is taken up. The product is stable in quality because it causes process instability such as the product cannot be taken out from the winder support, and it becomes difficult to widen the fabric in higher processes. Is not good. The lower limit of the fiber shrinkage rate is more preferably 9.8% or more, and further preferably 10.5% or more. By setting the fiber shrinkage ratio to 9.8% or more, it is possible to obtain a very excellent fabric with high windproof properties. When the fiber shrinkage rate is set to 10.5% or more, the windproof performance is further improved and the fabric is extremely windproof. Can be obtained.

  In order to obtain a fabric having an appropriate windproof property and softness, the shrinkage stress peak value is preferably 0.2 to 0.5 cN / dtex, and more preferably 0.23 cN / dtex or more. Is good. The initial tensile resistance of the composite fiber is preferably 20 to 40 cN / dtex. By setting the initial tensile resistance to 40 cN / dtex or less, a soft texture fabric can be obtained without impairing the softness of the 3GT polymer. Other physical properties are not particularly specified, but in order to obtain a composite fiber utilizing the characteristics of 3GT, the strength is preferably 3.0 to 5.0 cN / dtex, and the elongation is 30 to 60%. A composite fiber excellent in color developability and good handling in post-processing can be obtained. In order not to impair the characteristics of 3GT, it is easy to obtain good color developability when the elongation is 35% or more. When the split type composite fiber obtained in the present invention is made into a high-density woven fabric, it exhibits a very excellent windproof property, and when it is raised, a dense suede-like material in the raising direction can be obtained.

  Subsequently, the preferable manufacturing method of the composite fiber of this invention is demonstrated.

  The conjugate fiber of the present invention can be produced by any known method, but considering the stability and productivity of the composite structure, the production by the melt spinning method is the best. In the production by the melt spinning method, the yarn can be produced in any process, such as a method in which spinning and drawing processes are continuously performed, a method in which an undrawn yarn is wound once and then drawn, or a high-speed spinning method. Depending on, yarn processing such as false twisting or air entanglement may be performed. As an example, the production by the direct spinning drawing method will be described in detail below.

  In melt spinning the conjugate fiber of the present invention, 3GT as one component is preferably melted at 240 to 280 ° C. In the melting, a pressure melter method and an extruder method can be mentioned, and melting by an extruder is preferable from the viewpoint of uniform melting and prevention of stagnation. On the other hand, PLA which is the other component is preferably melted at 200 to 240 ° C. using an extruder similarly to 3GT. Separately melted polymers pass through separate pipes, weigh and then flow into the base pack. Under the present circumstances, it is preferable that piping passage time is 5 to 30 minutes from a viewpoint of suppressing thermal deterioration. The polymer that has flowed into the pack is merged by the die, and is combined into a form such as a sea-island type or a split-fiber type by a known technique and discharged from the die.

  In this case, the spinning temperature is suitably 240 to 270 ° C. If it is this range, the composite fiber which utilized the characteristic of 3GT can be manufactured.

  The polymer discharged from the die is cooled and solidified, and after the oil is applied, it is taken out. The take-up speed is possible at any speed of 1000-5500 m / min. In the case of drawing in an undrawn yarn or partially oriented yarn region of 100 to 4000 m / min, a method of pre-winding, drawing, and heat-treating to make a drawn yarn without winding is used. In the direct spinning drawing method described above, the draw ratio is suitably set so that the drawn yarn elongation is in the range of 30 to 60%. Further, in any of the spinning and drawing processes, it is possible to perform entanglement using a known entanglement device up to winding. If necessary, it is possible to increase the number of confounding by giving multiple times. Furthermore, it is also possible to add an oil agent immediately before winding.

  An outline of the apparatus preferably used is shown in FIG. The yarn once taken up at 1000 to 4000 m / min by the hot roller 8 heated to 40 to 80 ° C. is wound on the hot roller 8 for several turns for preheating, and the speed is 3800 to 5500 m / min. Then, it is drawn to the hot roller 9 and stretched. At this time, the hot roller 9 is heated to 110 to 170 ° C. and wound by several turns to perform heat setting. After provision of the entanglement, the tension is adjusted together with the cooling of the yarn by the two godet rollers 11 and 12, and it is wound around the package by a winder. In the winder, the package winding tension is adjusted by the contact roll 13 in contact with the package.

  By setting the contact roll speed to be 1.001 to 1.01 times faster than the winding speed of the package, it is possible to easily obtain a good bulge rate and ear height rate of the package. By setting the overfeed of the contact roll speed to be 1.001 or more, it is possible to reduce the tension when being wound around the package, and it is possible to suppress the swelling rate and the ear height rate. A more preferable range is 1.0015 or more. Moreover, the thread fall from a package end surface can be prevented by setting it as 1.01 or less, and favorable unwinding property can be ensured. A more preferable overfeed range is 1.008 or less. Furthermore, the yarn tension at the contact roll inlet is preferably 0.1 to 0.3 cN / dtex. By setting the tension to 0.1 cN / dtex or more, the yarn sway between the godet roller and the winder can be reduced, and the yarn can be stably wound even when the winding speed is increased. A more preferable tension is 0.12 cN / dtex or more. Further, when the tension is 0.3 cN / dtex or less, the tension control with the contact roll becomes easy and a good package foam can be obtained. A more preferable tension is 0.25 cN / dtex or less. Furthermore, the winding speed is preferably 3800 to 5000 m / min. By setting it as this range, high production efficiency can be maintained without impairing the physical properties of the composite fiber. A more preferable speed range is 3900 to 5000 m / min.

Hereinafter, an example is given and it demonstrates concretely. In addition, the main measured value of the Example was measured with the following method.
(1) Intrinsic viscosity Intrinsic viscosity [η] is a value determined based on the following defining formula.

Ηr in the definition formula is a value obtained by dividing the viscosity at 25 ° C. of a diluted solution of 3GT dissolved in O-chlorophenol having a purity of 98% or more by the viscosity of the solvent itself measured at the same temperature. Is defined. C is the solute weight value in grams in 100 ml of the solution.
(2) Strength, elongation, and initial tensile resistance Measured according to JIS L1013 (1999).
(3) Fiber shrinkage rate Fiber shrinkage rate (%) = {(L0−L1) / L0} × 100
L0: skein of raw yarn, skein length at a measurement load of 0.029 cN / dtex L1: treatment of raw yarn with no load in boiling water at 100 ° C. for 15 minutes, air drying, measurement load of 0.029 cN (4) Dyeability Tetraseal Navy Blue SGL 0.275% owf as a dye, Tetrocin PE-C 5.0% owf as an auxiliary agent, Nikkasan Salt # 12001.0% owf as a dispersant Was dyed at a bath ratio of 1: 100 at 50 ° C. for 15 minutes and further at 90 ° C. for 20 minutes. The dyed sample was subjected to a comprehensive sensory test for uneven dyeing and dyeing differences between drums and bobbins, and evaluated in three stages. In addition, a pass level is more than (circle).

○○: Very good ○: Excellent ×: PET equivalent (5) Windproof property A zokkoki woven fabric with a warp density of 5280 / m, a weft density of 3580 / m, and a raw machine width of 1.30 m was prepared at 95 ° C. After refining, the PLA component was removed by alkali reduction with 95 wt% or more with 3 wt% sodium hydroxide aqueous solution. Furthermore, after drying once at 130 ° C., finish heat setting was performed at 160 ° C. and a width of 110 cm. The fabric thus obtained was measured for air permeability according to JIS L1096 (1999) A method. Regarding the windproof property, the air permeability by the measurement was evaluated in the following three stages, and Δ or more was regarded as acceptable.

○○: 1 cc / cm ² . Less than sec ○: 1-2 cc / cm ² . sec
Δ: ^{2 to 3} cc / cm ² . sec
X: 3cc / cm < ² >. More than sec. (6) Softness The touch of the zokkoki woven fabric obtained by the above method was subjected to a sensory test and evaluated in three stages. In addition, a pass level is more than (circle).

○○: Very good ○: Excellent ×: Hard (7) Threading property The rate of yarn breakage at the time of spinning is converted to the value when it is produced by an 8-spindle winder, and yarn breakage is reduced. Those with 2 times / t or less were accepted (O), and those with more than 2 times / t were rejected (x).

Example 1
Poly-L-lactic acid with an optical purity of 98.0% and homo-3GT with an intrinsic viscosity of 1.1 were melted at 210 ° C. and 250 ° C. using an extruder, respectively, and weighed with a pump. In order to form a sea-island type composite form as shown in FIG. The composite ratio was 3GT7 with respect to polylactic acid 3. The passage time of each polymer for piping was 20 minutes for polylactic acid and 11 minutes for 3GT. The yarn discharged from the die is cooled by the apparatus shown in FIG. 3 and applied with an oil agent. Then, the yarn is taken up by the first hot roller 8 heated to 55 ° C. at a speed of 2700 m / min, and is temporarily wound up to 4300 m. The film was drawn around the second hot roller 9 heated to 150 ° C. at a speed of / min, and stretched and heat set. Further, after drawing the two godet rollers 11 and 12 at 4200 m / min, the tension at the contact roll inlet is 0.13 cN / dtex, the contact roll speed is 4080 m, and the package winding speed is 4072 m / min, that is, overfeed. Was wound up as 1.0020 to obtain 8 island-in-sea composite fibers of 64 dtex-36 filaments. The property evaluation results of this composite fiber are as shown in Table 1, and those excellent in windproof property, soft property and easy dyeability were obtained.

Example 2
The base is changed to a split type composite yarn of 64 dtex-36 filaments as shown in FIG. 2- (C), the tension at the contact roll inlet is 0.15 cN / dtex, the contact roll speed is 4070 m / min, and the package winding speed is 4062 m / min. The minutes, i.e. overfeed, was taken up as 1.0020. Conditions other than the above were the same as in Example 1. The obtained composite fibers were as shown in Table 1, and those excellent in windproof property, softness and easy dyeability were obtained.

Example 3
Using the same die as in Example 1, a composite ratio of PLA (sea): 3GT (island) was set to 2: 8, and 8 islands of sea-island composite fibers were obtained by the POY-DT process. During yarn production, after winding up once on a drum at a winding speed of 2800 m / min, the obtained raw yarn was preheated with a first roll at 70 ° C. and then drawn to a magnification of 1.47 times to obtain a second at 115 ° C. After heat setting with a roll, it was wound around a bobbin at 400 m / min via a third roll at room temperature to obtain the desired sea-island composite fiber. The obtained composite fiber was good in windproof property, soft property and dyeability.

Example 4
A sea-island composite fiber was obtained under the same conditions as in Example 1 except that the same die as in Example 1 was used and the first hot roller speed was 2500 m / min. The obtained composite fiber was windproof and soft but not as good as Example 1, but the dyeability was the same as Example 1.

Example 5
A sea-island composite fiber was obtained under the same conditions as in Example 1 except that the same die as in Example 1 was used and the first hot roller speed was 2300 m / min. The obtained composite fiber was windproof and soft but not as good as Example 1, but the dyeability was the same as Example 1.

Comparative Example 1
Using the same die as in Example 1, 5-sodium sulfoisophthalic acid copolymerized PET and 3GT were combined in a ratio of 3: 7 to try to make a yarn, but stable yarn production was impossible.

Comparative Example 2
Except that the second hot roller temperature was set to 170 ° C. and heat-set, the yarn was produced and evaluated in the same manner as in Example 1. As a result, the softness and dyeability were good, but the windproof property was poor.

Comparative Example 3
Using the same base as in Example 1, using 5-sodium sulfoisophthalic acid copolymerized PET as the sea component, using PET as the island component, and setting the sea: island composite ratio to 2: 8, the same as in Example 1. A composite fiber was obtained. However, the obtained composite fiber was slightly inferior in softness, and the dyeability and windproof property were much inferior to those in Example 1.

An example of a sea-island type composite fiber cross section is shown. An example of a split fiber type composite fiber cross section is shown. An example of a spinning process (direct spinning drawing method) is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Area | region which consists of a polymer which has polytrimethylene terephthalate as a main component 2 Area | region which consists of a polymer which has polylactic acid as a main component 3 Hollow part 4 Cap 5 Thread cooling air blower 6 Oil supply device 7 Entanglement device 8 First hot roll 9 Second hot roll 10 Entangling device 11 Gode roll 12 Gode roll 13 Contact roll 14 Package

Claims (4)

  A composite fiber composed of polyester A having polylactic acid as a main component and polyester B having polytrimethylene terephthalate as a main component, wherein polyester A occupies at least a part of the fiber surface, and the fiber shrinkage of the composite fiber Is a split type composite fiber characterized by being 9 to 20%.   2. The split type composite fiber according to claim 1, wherein the peak value of shrinkage stress is 0.20 to 0.50 cN / dtex.   The split type composite fiber according to claim 1 or 2, wherein an initial tensile resistance is 20 to 40 cN / dtex.   The fiber product which consists of a split type composite fiber of any one of Claims 1-3.

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