JP5220393B2 - Polyester composite long fiber - Google Patents

Description

  The present invention is a long fiber composed of a composite fiber that has a low melting point and excellent crystallinity so that it occupies at least a part of the fiber surface, and can be obtained with good operability, particularly as a binder fiber. The present invention relates to a polyester composite continuous fiber that is preferably used.

  Synthetic fibers, especially polyester fibers, are indispensable as clothing and industrial materials due to their excellent dimensional stability, weather resistance, mechanical properties, durability, and recyclability. Many polyester fibers are used.

  In recent years, from the viewpoint of environmental considerations, as an alternative to urethane-based and acrylic-based thermal adhesive resins, polyester fibers having thermal adhesiveness are being reviewed and can be used by being woven into fabrics because of their long fiber shape. From the viewpoint of ease of handling, there is a great demand for various clothing applications, interior applications such as chair upholstery and partitioning, and materials applications such as filters.

  As heat-adhesive fibers (binder fibers), core-sheath type composite fibers have been proposed in which polyethylene terephthalate is used as a core and a polyethylene terephthalate copolymer obtained by copolymerizing an isophthalic acid component is used as a sheath. Since this fiber is composed of a high melting point core and a low melting point sheath, the fiber shape is maintained without melting the core during heat treatment, and only the sheath is melted, thereby providing excellent strength. You can get a product.

  However, since the polyethylene terephthalate copolymer obtained by copolymerizing the isophthalic acid component in the sheath is amorphous and does not exhibit a clear crystal melting point, softening starts at a temperature above the glass transition point. For this reason, the long fiber obtained by melt spinning has a large thermal shrinkage during dyeing and thermal bonding treatment, and fabrics and fiber structures using this long fiber as at least a part thereof have poor dimensional stability. It was. In addition, it was inferior in heat resistance when used in a high temperature atmosphere.

  Patent Document 1 proposes a heat-adhesive polyester continuous fiber. This fiber has a core sheath in which polyethylene terephthalate is disposed in the core portion and a polyester copolymer obtained by copolymerizing a terephthalic acid component, an aliphatic lactone component, an ethylene glycol component, and a 1,4-butanediol component is disposed in the sheath portion. Type composite fiber.

  Since the polyester copolymer in the sheath portion is crystalline and has a clear melting point, the heat-bondable long fibers obtained by melt spinning have high strength and low thermal shrinkage.

  For this reason, this heat-adhesive polyester long fiber has a small shrinkage during dyeing and heat-bonding treatment, is excellent in dimensional stability, and has excellent heat resistance when used in a high-temperature atmosphere. You can get a product.

  However, the polyester copolymer of the sheath part has a melting point in the range of 150 to 200 ° C. and is not yet a low melting point region, and it is necessary to increase the processing temperature when thermally bonding. It was also disadvantageous in terms of cost.

Furthermore, in the melt spinning process when manufacturing the fiber, the polyester copolymer in the sheath is difficult to cool, and depending on the spinning and cooling conditions, welding between the yarns and sticking of the take-up package are likely to occur. In order to solve this problem, it is conceivable to lower the spinning temperature. However, in this method, there is a problem that melt spots occur, the spinning property is poor, and the operability is lowered.
JP 2006-118066 A

  The present invention solves the above problems, and by using a polyester having a low melting point and excellent crystallinity, it can be melt-spun and stretched with a normal production apparatus, and can be produced with good operability. Polyester long fiber, especially when used as a binder fiber, it can be processed at a low temperature when thermally bonded, and products such as fabrics and fiber structures having excellent dimensional stability can be obtained. An object of the present invention is to provide an environment-friendly polyester composite long fiber using a plant-derived component by using a polylactic acid-based polymer as the other component.

The inventors of the present invention have arrived at the present invention as a result of studies to solve the above problems.
That is, the present invention is, dicarboxylic acid component terephthalic acid only, the diol component is composed of 1,6-hexanediol and ethylene glycol only, or only 1,6-hexanediol and 1,4-butanediol, a diol In the component, DSC is 50 mol% or more, contains 0.5 to 3.0 % by mass of a crystal nucleating agent, has a melting point of 100 to 150 ° C., and exhibits a temperature-falling crystallization determined by DSC A long fiber of a composite fiber composed of a polyester A having a curve satisfying the following formula (1) and a polylactic acid polymer having a melting point 30 ° C. higher than the melting point of the polyester A. A polyester composite continuous fiber characterized in that polyester A is arranged so as to occupy at least a part of the fiber surface in the surface shape. A.
b / a ≧ 0.05 (mW / mg · ° C.) (1)
Note that a is the temperature A1 (° C.) of the intersection between the tangent line and the baseline having the maximum inclination in the DSC curve indicating the temperature-falling crystallization, and the temperature A2 (° C.) of the intersection of the tangent line and the baseline having the minimum inclination. B) is the difference (B1-B2) between the baseline heat quantity B1 (mW) and the peak top heat quantity B2 (mW) at the peak top temperature (mg) The value divided by.

  The polyester composite long fiber of the present invention has a low melting point and excellent crystallinity, and in particular, polyester A, which has a high crystallization rate when the temperature is lowered, is used on the fiber surface. Therefore, the yarn is used in the melt spinning process when producing the fiber. There is no occurrence of welds between strands, spun yarns accompanying it, and the occurrence of sticking of the take-up package, and it can be obtained with high productivity. And the extending | stretching and heat processing process can also be performed with sufficient operativity, it can have sufficient intensity | strength and a thing with a low hot-water shrinkage rate.

  In particular, when the polyester composite long fiber of the present invention is used as a binder fiber, it can be processed at a low temperature when thermally bonded, which is advantageous in terms of cost. Furthermore, it has the strength that can withstand twisted yarn processing, weaving, knitting, etc., and can be used for various processed yarns, fabrics, and fiber structures.

  In addition, since the hot water shrinkage rate is low, products such as processed yarns, fabrics, and fiber structures using the polyester composite long fiber of the present invention at least in part have dimensional stability and form after thermal bonding treatment. Excellent retention, adhesion part does not peel off even during dyeing treatment and hot water treatment after adhesion, and it can maintain its adhesion even when used in a high temperature atmosphere. ).

  Furthermore, since the polyester composite long fiber of the present invention uses a polylactic acid polymer together with polyester A, it is a long fiber using a plant-derived component and is environmentally friendly.

Hereinafter, the present invention will be described in detail.
The polyester composite long fiber of the present invention is composed of polyester A and a polylactic acid polymer, and is a composite fiber in which polyester A occupies at least a part of the fiber surface. That is, the composite continuous fiber of the present invention may be a multifilament or a monofilament, but in a cross-sectional shape of a single yarn (a cross-sectional shape cut perpendicularly along the fiber axis direction), the polyester A has at least a part of the fiber surface. Occupies.

  Examples of such shapes include side-by-side type, eccentric core-sheath type, multilayer type, etc. Among them, polyester A is the sheath part and polylactic acid polymer is arranged at the core part in the cross-sectional shape of the single yarn. The core-sheath shape is preferable.

  First, polyester A will be described. Polyester A is a copolyester having a melting point of 100 to 150 ° C. composed of a dicarboxylic acid component containing terephthalic acid as a main component and a diol component of 1,6-hexanediol of 50 mol% or more.

  Polyester A has a melting point (Tm) of 100 to 150 ° C., preferably 105 to 140 ° C., more preferably 110 to 130 ° C. When the Tm is less than 100 ° C., the product obtained from the long fiber of the present invention is inferior in thermal stability (heat resistance) when used in a high temperature atmosphere. On the other hand, if the temperature exceeds 150 ° C., it is necessary to increase the heat bonding processing temperature when obtaining the product, which is inferior in workability and economy. Further, it is not preferable because the quality and texture of the product obtained by the heat treatment are impaired.

  Polyester A has terephthalic acid as a main component as a dicarboxylic acid component, and terephthalic acid (hereinafter referred to as TPA) is preferably 60 mol% or more, more preferably 80 mol% or more. If the TPA is less than 60 mol%, the melting point of the polymer is not within the scope of the present invention, and the crystallinity tends to be lowered, which is not preferable.

  In addition, as a copolymerization component other than TPA, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid are within the range that does not impair the effect. Acid, saturated aliphatic dicarboxylic acid exemplified by 1,4-cyclohexanedicarboxylic acid, dimer acid and the like, or ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acid exemplified by fumaric acid, maleic acid, itaconic acid and the like Aromatic dicarboxylic acids exemplified by these ester-forming derivatives, phthalic acid, isophthalic acid, 5- (alkali metal) sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like These ester-forming derivatives can be used.

  As the diol component, 1,6-hexanediol (hereinafter referred to as HD) is 50 mol% or more, and as other components, ethylene glycol (hereinafter referred to as EG) or 1,4-butanediol (hereinafter referred to as HD). BD) is preferably used. In the diol component, HD is 50 mol% or more, and preferably 60 to 95 mol%. When HD is less than 50 mol%, the melting point exceeds 150 ° C.

  When EG or BD is used together with HD as the diol component, EG or BD is preferably 5 to 50 mol%, more preferably 5 to 40 mol% in the diol component.

  Furthermore, the diol component includes other copolymer components other than HD, EG and BD, as long as the properties are not impaired, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, tetra For ethylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol, etc. Exemplified aliphatic glycol, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, bisphenol A, 2,5-naphthalenediol, ethylene oxide is included in these glycols Aromatic glycols exemplified such as pressurized the glycol may be employed.

  And polyester A contains 0.01-5.0 mass% of crystal nucleating agents, and it is preferable to contain 0.5-3.0 mass% especially.

  Polyester A has crystallinity due to the copolymer composition as described above, but by containing a crystal nucleating agent, the crystallization rate at the time of cooling can be improved and melted. It is possible to prevent welding between single yarns in the spinning process and sticking of the take-up package. And the polyester composite long fiber of this invention can satisfy | fill (1) Formula mentioned later.

  When the content of the crystal nucleating agent is less than 0.01% by mass, the crystallization speed at the time of temperature reduction cannot be improved, and the polyester composite long fiber of the present invention satisfies the formula (1) described later. Can not. On the other hand, if it exceeds 5.0% by mass, the content of the crystal nucleating agent is excessively increased, the operability during spinning and drawing is deteriorated, and the fiber has low strength and quality.

  As the crystal nucleating agent, it is preferable to use inorganic fine particles, polyolefin, sulfate or the like.

As the inorganic fine particles, those mainly composed of silicon oxide such as talc are preferable, and inorganic fine particles having an average particle size of 3.0 μm or less or a specific surface area of 15 m ² / g or more are preferably used. When the average particle size or specific surface area is not satisfied, the function as a crystal nucleus is poor, and the polyester composite long fiber of the present invention tends to be difficult to satisfy the formula (1) described later.

  The polyolefin contained as a crystal nucleating agent melts in the reaction system, so the shape is not particularly limited. For example, a chip-like one having a particle size of about 2 mm or a wax-like one having a particle size of several μm It may be.

  Examples of polyolefins include olefin homopolymers such as polyethylene, polypropylene, poly-1-butene, polymethylpentene, and polymethylbutene, and propylene / ethylene random copolymers. Polyethylene, polypropylene, poly-1- Butene and propylene / ethylene random copolymers are particularly preferred. In the case where the polyolefin is a polyolefin obtained from an olefin having 3 or more carbon atoms, it may be an isotactic polymer or a syndiotactic polymer.

  Examples of the sulfate to be contained as a crystal nucleating agent include lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, barium sulfate, calcium sulfate, and aluminum sulfate. And magnesium sulfate are preferred.

  As a method for adding these crystal nucleating agents, they may be added at an arbitrary stage when the polyester is produced in the form of powder or in the form of a diol slurry. For example, it may be added at the time of esterification or transesterification, or may be added at the stage of polycondensation reaction. Among these, in order to improve the effect as a crystal nucleating agent, it is preferable to add in a slurry state or a dissolved state in a glycol such as ethylene glycol.

  In the polyester A, a stabilizer such as a phosphate ester compound or a hindered phenol compound, a cobalt compound, a fluorescent brightener, a color tone improver such as a dye, One kind or two or more kinds of various additives such as a matting agent, a plasticizer, a pigment, an antistatic agent, a flame retardant, and a dyeing agent may be added.

Polyester A has a DSC curve showing temperature-fall crystallization determined by DSC satisfying the following formula (1), and it is particularly preferable that b / a ≧ 0.06. On the other hand, the larger b / a, the better the crystallinity when the temperature is lowered. However, in order to achieve the intended effect of the present invention, b / a is preferably 0.5 or less.
b / a ≧ 0.05 (mW / mg · ° C.) (1)

  The DSC curve showing the melting temperature of polyester A in the present invention and the temperature-falling crystallization obtained from DSC is a temperature range of −20 ° C. to 250 ° C. in a nitrogen stream using a differential scanning calorimeter (Diamond DSC) manufactured by PerkinElmer. Measured at a rate of temperature increase (temperature decrease) of 20 ° C./min and a sample amount of 2 mg (the mass of long fibers)

  Said b / a is calculated | required from the DSC curve which shows the temperature-fall crystallization calculated | required from DSC. At this time, there are two peaks of polyester A and polylactic acid polymer that form long fibers, but the DSC curve of the peak that appears on the low temperature side is that of polyester A.

  As shown in FIG. 1, a is the temperature A1 (° C.) of the intersection of the tangent line and the base line with the maximum inclination in the DSC curve indicating the temperature-falling crystallization, the tangent line and the base line with the minimum inclination. Is the difference (A1−A2) from the temperature A2 (° C.) at the intersection of the two, and b is the difference (B1−B2) between the baseline heat amount B1 (mW) and the peak top heat amount B2 (mW) at the peak top temperature. ) Divided by the sample amount (mg).

  b / a is an index representing the crystallinity when the temperature is lowered, and the higher the b / a value, the faster the crystallization rate, and vice versa, the closer to 0, the slower the crystallization rate. When b / a is less than 0.05 (mW / mg · ° C), the crystallization rate at the time of temperature decrease becomes slow, and during melt spinning, welding between single yarns and sticking of the winding package occur, and stable production is achieved. It becomes difficult.

  As described above, b / a can be within the range specified in the present invention by setting the copolymer composition of polyester A to a specific value and the content of the crystal nucleating agent within the above range. it can.

  Next, the polylactic acid polymer will be described. Polylactic acid-based polymers include poly-D-lactic acid, poly-L-lactic acid, poly-DL-lactic acid, which is a copolymer of poly-D-lactic acid and poly-L-lactic acid, and poly-D-lactic acid and poly-L-lactic acid. Mixture (stereo complex), copolymer of poly D-lactic acid and hydroxycarboxylic acid, copolymer of poly L-lactic acid and hydroxycarboxylic acid, poly D-lactic acid or poly L-lactic acid and aliphatic dicarboxylic acid and fat A copolymer with a group diol or a blend thereof can be used.

  The polylactic acid polymer has a melting point that is 30 ° C. or more higher than the melting point of polyester A, and preferably 40 ° C. or more. As described above, when L-lactic acid or D-lactic acid is used alone, the melting point is about 180 ° C., but in the case of a copolymer of D-lactic acid and L-lactic acid, the ratio of either component is 10 mol. When it is about%, the melting point is about 130 ° C.

  Therefore, as polylactic acid, L / D or D / which is the content ratio (molar ratio) of L-lactic acid and D-lactic acid indicated by the content ratio of L-lactic acid or D-lactic acid when polymerizing using lactide as a raw material. L is preferably 90/10 or more, more preferably 95/5 or more, and even more preferably 98/2 or more.

  Among polylactic acids, a mixture (stereocomplex) of poly D-lactic acid and poly L-lactic acid as described above is particularly preferable because it has a high melting point of 200 to 230 ° C. and high strength in a high temperature atmosphere. .

  The polyester composite long fiber of the present invention is preferably used as a binder fiber by using polyester A as a low melting point polyester and polylactic acid polymer as a high melting point polyester. It is preferable that the polymer melts to become an adhesive component, and the polylactic acid polymer does not melt and is used as a main fiber. Therefore, when obtaining products such as processed yarns and woven or knitted fabrics, only the polyester composite long fibers of the present invention may be used, or the polyester composite long fibers of the present invention and other fibers serving as main fibers may be used together. Also good.

  When the difference between the melting point of the polylactic acid polymer and the melting point of the polyester A is less than 30 ° C., when the polyester A is melted by the thermal bonding treatment, the polylactic acid polymer is also melted or deteriorated. Products such as processed yarns and knitted and knitted fabrics are inferior in mechanical properties and quality.

  In addition, the polylactic acid-based polymer in the present invention includes cyclic lactones such as ε-caprolactone, α-hydroxy such as α-hydroxybutyric acid, α-hydroxyisobutyric acid, α-hydroxyvaleric acid and the like within a range not to impair the purpose. Acids, glycols such as ethylene glycol and 1,4-butanediol, and dicarboxylic acids such as succinic acid and sebacic acid may be contained.

  The composite ratio (mass ratio) of the polyester A and the polylactic acid polymer of the polyester composite long fiber of the present invention is preferably 20/80 to 80/20, and more preferably 30/70 to 70/30. preferable. If the polyester A component is less than this, the adhesive component is insufficient and the binder fiber tends to be unsuitable. On the other hand, if the amount of the polylactic acid-based polymer is less than this, products such as processed yarns and woven / knitted fabrics that are obtained tend to be insufficient in strength.

  Furthermore, the polyester composite long fiber of the present invention preferably has a hot water shrinkage at 100 ° C. of 17% or less, more preferably 15% or less, and further preferably 12% or less.

  When the hot water shrinkage rate at 100 ° C. exceeds 17%, the texture of these products tends to harden or the dimensional stability tends to deteriorate after a processed yarn, a fabric, a molded body or the like is subjected to heat bonding treatment. And since the polymer lump which is formed when the fiber is melted by the thermal bonding treatment is scattered and does not go to the intersection of the fibers on the non-adhesive body, the adhesiveness tends to be lowered. Further, the adhesion site is easily peeled off during the dyeing process and the hot water process after bonding.

  The hot water shrinkage in the present invention is measured in accordance with the skein shrinkage (Method A) of the hot water shrinkage of JIS L-1013.

  Further, the polyester composite long fiber of the present invention preferably has a strength of 1.0 cN / dtex or more, more preferably 1.5 cN / dtex or more, and further 2.0 cN / dtex or more. Preferably there is. If the strength is less than 1.0 cN / dtex, yarn breakage may occur due to the tension and scratch resistance in the false twisting process, the mixed fiber processing process using air or interlace, and the weaving process. The permeability is poor and the quality of the resulting product is likely to deteriorate.

  Further, the strength in the present invention is measured according to a standard time test of tensile strength and elongation of JIS L-1013, using a tensile tester RTC-1210 type manufactured by ORIENTEC Co., Ltd., with a grip interval of 50 cm and a tensile speed of 50 cm / min. Is.

  Since the polyester composite long fiber of the present invention uses polyester A having a low melting point and high crystallinity and a high temperature-falling crystallization speed on the fiber surface, an undrawn yarn obtained by melt spinning is temporarily used. In both the two-step method of drawing after winding and the one-step method of continuously drawing undrawn yarn without winding it once, welding between yarns in the spinning step, spun yarn breakage associated therewith, There is no sticking of the take-up package and it can be obtained with good productivity and quality. Further, stretching and heat treatment can be performed with good operability. By adjusting the stretching ratio and heat treatment temperature, the strength is such that the strength is 1.0 cN / dtex or more and the hot water shrinkage at 100 ° C. is 17% or less. It can be a fiber.

  The following is mentioned as an example in which the polyester composite long fiber of this invention is used suitably. It can be formed into a mixed yarn made by mixing a part of a plurality of fibers, and the polyester A of the composite long fiber can be melted by heat treatment (thermal bonding treatment) to form an adhesive component, which can be formed into an arbitrary shape. It can be used as a bristle part used for a bristle part or a pile thread for carpets. Moreover, it can be used as a core material which adhere | attaches fabrics by using for one part of the fiber which comprises a woven / knitted fabric, making a woven / knitted fabric, and making polyester A fuse | melt by heat-processing and making it an adhesive component. Similarly, a part of the fibers constituting the woven fabric can be used as a woven fabric, and by applying heat treatment, the polyester A can be melted and used as an adhesive component so that the fibers constituting the woven fabric can be bonded to each other. Such a fabric can be used as a filter.

  In addition, since the polyester composite long fiber of the present invention uses a polylactic acid polymer together with polyester A, after the polyester A melts, the polylactic acid polymer becomes a main fiber. It is made of fiber and can be made into a product that is friendly to the global environment.

  Further, the single yarn fineness of the polyester composite long fiber of the present invention is not particularly limited. However, when used for the above-mentioned applications, it is preferably 1 to 50 dtex, particularly 3 to 30 dtex.

  And the cross-sectional shape is not particularly specified, but it is not only a round shape but also a flat shape, a trilobal shape, a hexaloval shape, a W shape, an H shape, etc., a polygonal shape such as a rectangle or a triangle, or a hollow shape But you can.

  Next, the manufacturing method of the polyester composite long fiber of this invention is demonstrated using an example. First, a dicarboxylic acid component and a diol component are esterified or transesterified, and a crystal nucleating agent is added to perform a polycondensation reaction. When the polyester reaches a predetermined intrinsic viscosity in the polycondensation reaction, it is discharged into a strand shape, cooled and cut into chips to obtain polyester A. Next, the polyester A chip and the polylactic acid polymer chip are supplied to a composite spinning apparatus, and melt spinning is performed so that the polyester A serves as a sheath and the polylactic acid polymer serves as a core. After melt spinning, the unstretched yarn that has been cooled and solidified and provided with the oil agent is wound once or continuously without being wound. When the undrawn yarn is drawn, the polyester composite long fiber of the present invention is obtained by drawing at a draw ratio of 1.3 to 4.0 times between a plurality of rollers and performing heat treatment as necessary.

  When winding the undrawn yarn once, it is preferable that the spinning speed is 2500 to 4000 m / min and wound into a package as a highly oriented undrawn yarn to keep the draw ratio during drawing low. A processed yarn using the polyester composite continuous fiber of the present invention can be obtained by performing composite processing such as false twisting using highly oriented undrawn yarn or mixing with air or interlace.

Next, the present invention will be specifically described using examples. Measurement and evaluation of various characteristic values in the examples were performed as follows.
(A) Average particle diameter of inorganic fine particles (talc) The average particle diameter of the sample in ethylene glycol was measured using a particle size distribution measuring device (SALD-2000) manufactured by Shimadzu Corporation.
(B) Specific surface area of inorganic fine particles (talc) Measured by the BET method.
(C) Intrinsic viscosity [η]
Measurement was carried out based on a conventional method under the conditions of a sample concentration of 0.5% by mass and a temperature of 20 ° C. using an equal mass mixture of phenol and ethane tetrachloride as a solvent.
(D) Melting point of polyester A, DSC curve showing temperature drop crystallization determined from DSC Measured by the above method.
(E) Polymer composition of polyester A The obtained polyester composite long fiber was dissolved in a mixed solvent having a volume ratio of 1/20 of deuterated hexafluoroisopropanol and deuterated chloroform, and LA-400 NMR produced by JEOL Ltd. 1H-NMR was measured with an apparatus and determined from the integrated intensity of the proton peak of each copolymer component in the obtained chart.
(F) Content of L-lactic acid and D-lactic acid in polylactic acid-based polymer Measured by a high performance liquid chromatography method using an equal mass mixed solution of ultrapure water and a methanol solution of 1N sodium hydroxide as a solvent. Sumichiral OA6100 was used for the column, and it detected with the UV absorption measuring device.
(G) Spinning operability 24 hours of operation was performed with 16 spindles, and the following three stages were evaluated according to the spinning conditions.
○: Number of yarn breakage during spinning is 3 or less △: Number of yarn breakage during spinning is 4-9 times ×: Number of yarn breakage during spinning is 10 times or more (h) Strength, elongation,
According to the standard time test of the tensile strength and elongation rate of JIS L-1013, the tensile tester RTC-1210 manufactured by ORIENTEC Co. was used and the measurement was performed at a grip interval of 50 cm and a tensile speed of 50 cm / min.
(I) Hot water shrinkage rate Measured by the above method.
(J) Adhesiveness Mixing together one obtained polyester composite long fiber and two polyester long fibers mainly composed of polyethylene terephthalate (84 dtex / 36 fil, strength 4.3 cN / dtex, elongation 35%) Then, twisting is performed by rotating the spindle in the middle of the fiber mixing process to obtain a twisted yarn of 15 / m. Both ends of the twisted yarn are cut and stretched to 10 cm, and both ends are fixed. Then, thermocompression bonding is performed in the fiber axis direction under conditions of a roller temperature of 120 ° C., a roller speed of 0.5 m / min, and a press pressure of 0.7 kg / cm ^2. Both ends were cut to obtain a sample having a length of 5 cm.
This sample was put into a glass 300 ml beaker, and stirred in hot water heated to 95 ° C. for 30 minutes at a rotation speed of 200 rpm with a rugby ball type magnetic stirrer having a width of 4 cm. About 10 samples, the stirring process was performed, the sample after processing was naturally dried, the peeling state of the fiber after drying was observed visually, and the following three steps evaluated.
○: No peeling in all samples △: There is a sample that is partially peeled ×: There are 5 or more samples that are peeled and do not maintain the form of twisted yarn

Example 1
The slurry of TPA and EG is continuously supplied to the esterification reactor and reacted under the conditions of a temperature of 250 ° C. and a pressure of 0.2 MPa, and a residence time of 8 hours is obtained to obtain a reaction product with an esterification reaction rate of 95%. It was. This reaction product was transferred to a polycondensation reaction vessel, HD was charged into the polycondensation reaction vessel, and stirred at a temperature of 240 ° C. and normal pressure for 1 hour. Next, EG slurry containing talc having an average particle size of 1.0 μm and a specific surface area of 35 m ² / g as a crystal nucleating agent was put into a polycondensation reaction can, and then the pressure in the reactor was gradually reduced while stirring. The polycondensation reaction was carried out for about 3 hours, and the polyester A was obtained by cutting out into strands by a conventional method and forming chips. Polyester A consists of 100 mol% TPA as an acidic component, 15 mol% EG as a glycol component, and 85 mol% HD, contains 1.0% by mass of talc as a crystal nucleating agent, has a b / a of 0.07, an intrinsic viscosity of 0.95, The melting point was 128 ° C.
As a polylactic acid polymer, polylactic acid having a content ratio of L-lactic acid to D-lactic acid of 98.8 / 1.2, a melting point of 170 ° C., a relative viscosity of 1.85, and a number average molecular weight of 81,200 is used. It was.
The polyester A chip and the polylactic acid chip were supplied to the composite spinning apparatus, and the polyester A was the sheath and the polylactic acid was the core, and the melt spinning was performed with the composite ratio (mass ratio) of both components being 50/50. . At this time, spinning was performed using a spinneret with a spinning temperature of 220 ° C., a total discharge amount of 32.7 g / min, and a spinning hole number of 48 and a spinning speed of 3000 m / min. Next, after cooling the spun yarn, an oil agent was applied and bundled to obtain a highly oriented undrawn yarn of 109 dtex / 48 fil.
Next, this highly oriented undrawn yarn is taken up by a first roller having a surface temperature of 50 ° C., and a heat plate heated to 115 ° C. is installed between the second roller (preheating temperature 50 ° C., heat setting temperature). 115 ° C.) and heat drawing was performed at a draw ratio of 1.3 times to obtain a 84 dtex / 48 fil polyester composite continuous fiber.

Examples 2-3 and Comparative Examples 1-2
A polyester composite long fiber was obtained in the same manner as in Example 1, except that the amount of the crystal nucleating agent (talc) added in the polyester A was changed to the content in the polyester A shown in Table 1.

Example 4
TPA, HD, and BD are supplied to the esterification reactor, talc having an average particle size of 1.0 μm and a specific surface area of 35 m ² / g is added as a crystal nucleating agent, and the temperature is 230 ° C. and the pressure is 0.2 MPa. After stirring for a period of time and carrying out an esterification reaction, it was transferred to a polycondensation reaction can. Then, the pressure in the reactor was gradually reduced, and the polycondensation reaction was carried out for about 3 hours with stirring. Polyester A is composed of 100 mol% of TPA as an acidic component, 20 mol% of 1,4-butanediol (BD) as a glycol component, and 80 mol% of HD, contains 1.0% by mass of talc as a crystal nucleating agent, and b / a is 0 .13, intrinsic viscosity 0.98, melting point 130 ° C.
As the polylactic acid polymer, the same polylactic acid as in Example 1 was used, and melt spinning and stretching were performed in the same manner as in Example 1 to obtain a polyester composite long fiber.

Examples 5-6, Comparative Examples 3-4
A polyester composite long fiber was obtained in the same manner as in Example 4, except that the amount of talc added to the crystal nucleating agent in polyester A was changed to the content in polyester A shown in Table 1.

Comparative Example 5
Polyester A consists of 100 mol% TPA as an acidic component, 60 mol% EG as a glycol component, and 40 mol% HD, contains 1.0% by mass of talc as a crystal nucleating agent, has a b / a of 0.07, an intrinsic viscosity of 0.95, A polyester composite long fiber was obtained in the same manner as in Example 1 except that one having a melting point of 158 ° C was used.

Comparative Example 6
Polyester A is composed of 100 mol% TPA as an acidic component, 60 mol% BD as a glycol component, and 40 mol% HD, contains 1.0% by mass of talc as a crystal nucleating agent, has a b / a of 0.12, an intrinsic viscosity of 0.98, A polyester composite long fiber was obtained in the same manner as in Example 1 except that one having a melting point of 158 ° C was used.

Comparative Example 7
After obtaining the highly oriented undrawn yarn, the polyester composite length was the same as in Example 2 except that the temperature of the first roller and the heat plate was set to room temperature (no heat setting was performed during drawing). Fiber was obtained.

  Table 1 shows the characteristic values and evaluation results of the polyester composite long fibers obtained in Examples 1 to 6 and Comparative Examples 1 to 7.

  As is clear from Table 1, the polyester composite long fibers of Examples 1 to 6 are those in which the polyester A in the sheath satisfies the formula (1), has high crystallinity, and can be obtained with good spinning operability. It was. Further, stretching and heat treatment could be performed satisfactorily, the strength was 2.1 cN / dtex or more, and the strength was sufficient to withstand use in post-processing steps such as twisted yarn and knitting. Furthermore, the hot water shrinkage rate was as low as 11% or less, the dimensional stability during heat bonding was excellent, and the evaluation of adhesion was also good.

  On the other hand, the polyester composite long fibers of Comparative Examples 1 and 3 have a low content of the crystal nucleating agent in the polyester A, the polyester A does not satisfy the formula (1), and the crystallization rate during cooling is slow. Therefore, the yarns were welded during spinning, and the spinning operability was poor. In the polyester composite long fibers of Comparative Examples 2 and 4, since the content of the crystal nucleating agent in the polyester A was large, cut yarns were generated during spinning and the operability was poor. Furthermore, the strength was low and the adhesiveness was poor. In the polyester composite long fibers of Comparative Examples 5 and 6, since the polyester A had an HD content of less than 50 mol% and a melting point of more than 150 ° C., cut yarns were generated during spinning, and adhesion Even when heat treatment was performed on the twisted yarn at a roller temperature of 120 ° C. during the evaluation of the above, it was not sufficiently thermally bonded, peeling occurred in all the samples, and the shape of the twisted yarn was not maintained. Since the polyester composite long fiber of Comparative Example 7 was a fiber having a high hot-water shrinkage ratio that did not sufficiently heat-stretch the highly oriented undrawn yarn, the shrinkage during the heat bonding treatment was large, and the polyester A melted. Since the components were scattered, the adhesion evaluation was low.

It is an example of the DSC curve which shows the temperature-fall crystallization calculated | required from DSC of the polyester A in this invention.

Claims (3)

The dicarboxylic acid component is composed of terephthalic acid only , the diol component is composed of only 1,6-hexanediol and ethylene glycol, or 1,6-hexanediol and 1,4-butanediol. The diol is 50 mol% or more, contains 0.5 to 3.0 % by mass of a crystal nucleating agent, has a melting point of 100 to 150 ° C., and a DSC curve showing the temperature-falling crystallization determined by DSC has the following formula (1) Is a long fiber of a composite fiber composed of a polyester A satisfying the above and a polylactic acid polymer having a melting point 30 ° C. higher than the melting point of the polyester A, and the polyester A is a fiber in a cross-sectional shape of a single yarn A polyester composite long fiber characterized by being arranged so as to occupy at least a part of the surface.
b / a ≧ 0.05 (mW / mg · ° C.) (1)
Note that a is the temperature A1 (° C.) of the intersection between the tangent line and the baseline having the maximum inclination in the DSC curve indicating the temperature-falling crystallization, and the temperature A2 (° C.) of the intersection of the tangent line and the baseline having the minimum inclination. B) is the difference (B1-B2) between the baseline heat quantity B1 (mW) and the peak top heat quantity B2 (mW) at the peak top temperature (mg) The value divided by. The polyester composite long fiber according to claim 1, wherein the crystal nucleating agent is mainly composed of silicon oxide. The polyester composite long fiber according to claim 1 or 2 , having a strength of 1.0 cN / dtex or more and a hot water shrinkage at 100 ° C of 17% or less.