JP2018071011A - Split type conjugate fiber and nonwoven fabric using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a split type conjugate fiber composed of a polybutylene terephthalate resin and a polypropylene resin and having excellent spinnability and splittability, and a nonwoven fabric having excellent mechanical strength, uniformity and flexibility in which the split type conjugate fiber is split.SOLUTION: The split type conjugate fiber of the present invention comprises a first component containing the polybutylene terephthalate resin having a melting point of 180 to 220°C and a second component containing the polypropylene resin, wherein a conjugation ratio of the first component to the second component is 10-70 mass% to 90-30 mass%, the first component or the second component is divided into two or more as seen from a cross section of the fiber, and at least a part of the first component and the second component is exposed on a fiber surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a split-type composite fiber and a nonwoven fabric composed of ultrafine fibers using the same.

  Nonwoven fabrics made of ultrafine fibers are excellent in uniformity and flexibility, and are widely used as materials for disposable diapers, hygiene products, and wiping cloths.

  As a method for obtaining a non-woven fabric composed of ultrafine fibers, there are known techniques for dividing non-woven fabrics composed of split-type conjugate fibers into non-woven fabrics composed of ultrafine fibers by heat treatment or physical treatment. Proposals have been made.

  For example, a nonwoven fabric composed of split type composite fibers made of a specific polypropylene resin and a polyolefin resin of a polyethylene resin has been proposed (see Patent Document 1). However, even if a specific resin is used as in this proposal, it is difficult to say that the splitting property is sufficient because the polyolefin resins have high compatibility.

  In addition, as a non-woven fabric made of ultrafine fibers having excellent splitting properties, a method of splitting a non-compatible polyester non-woven fabric made of a split fiber of a polymer of a polyolefin resin and a water-jet punch has been proposed (patent) Reference 2). Certainly, according to this proposal, a combination of an incompatible polyester-based resin and a polyolefin-based resin is excellent in separability, but the two components specifically described in this proposal are polylactic acid. And propylene / ethylene random copolymer, but the spinnability is unstable, and since the spinning speed described is at most 2500 m / min, polylactic acid is not sufficiently oriented and crystallized. There was a problem of being scarce.

Thus, the nonwoven fabric comprised from the split type composite fiber excellent in both spinnability and splitting property has not been obtained.
JP 2012-140734 A JP 2007-247072 A

  Therefore, in view of the above-mentioned problems, the object of the present invention is to be flexible and excellent in formation formed by a split type composite fiber excellent in both spinnability and splitability, and an ultrafine fiber using the split type composite fiber. It is to provide a non-woven fabric.

  The split type composite fiber of the present invention comprises a first component containing a polybutylene terephthalate resin having a melting point of 180 to 220 ° C. and a second component containing a polypropylene resin, and the composite ratio is 10 to 70. Mass%: 90 to 30% by mass of the fiber, wherein the first component or the second component is divided into two or more when viewed from the cross section of the fiber, and the first component and the A split-type composite fiber characterized in that at least a part of the second component is exposed on the fiber surface.

  In the nonwoven fabric of the present invention, the split type composite fiber constituting the nonwoven fabric composed of the split type composite fiber is split, and the average fiber diameter of the split single fiber is 1.0 to 8.0 μm. Is a nonwoven fabric characterized by

  According to the preferable aspect of the nonwoven fabric of this invention, the nonwoven fabric which consists of said split-type composite fiber is manufactured with the spunbond method.

  According to the present invention, it is possible to obtain a split nonwoven fabric excellent in spinnability and splitting properties, and a flexible nonwoven fabric composed of ultrafine fibers obtained by splitting the splittable composite fibers. .

FIG. 1 is a schematic cross-sectional view illustrating a cross section (a cross section perpendicular to the fiber length direction) of a split composite fiber in the present invention.

  The split type composite fiber of the present invention comprises a first component containing a polybutylene terephthalate resin having a melting point of 180 to 220 ° C. and a second component containing a polypropylene resin, and the composite ratio is 10 to 70. Mass%: 90 to 30% by mass of the fiber, wherein the first component or the second component is divided into two or more when viewed from the cross section of the fiber, and the first component and the It is a split type composite fiber in which at least a part of the second component is exposed on the fiber surface.

  It is important that the first component polybutylene terephthalate resin specified in the present invention has a melting point in the range of 180 ° C to 220 ° C.

  In general, in the case of melt spinning a polyester resin, it is known that a preferable spinning temperature is a melting point +20 to 40 ° C. On the other hand, when spinning a polypropylene resin, the spinning temperature is often 220 to 250 ° C. in many cases. In the case of a polypropylene resin, when the spinning temperature is 250 ° C. or higher, it is difficult to cool because the specific heat of the resin is high, and spinning may become unstable, for example, the spun yarns are fused.

  By controlling the melting point of the first component polybutylene terephthalate resin used in the present invention to 180 ° C. to 220 ° C., preferably 190 ° C. to 220 ° C., more preferably 200 to 210 ° C., the first component polybutylene It becomes possible to set the spinning temperature 220 to 250 ° C. suitable for both the terephthalate resin and the second component polypropylene resin, and the splitting composite fiber having excellent strength is obtained with stable spinning even at a high spinning speed. be able to.

  In a preferred embodiment, the first component polybutylene terephthalate resin used in the present invention is a polybutylene terephthalate / isophthalate copolymer. Polybutylene terephthalate / isophthalate copolymer is a copolymer of terephthalic acid and isophthalic acid and 1,4-butanediol, and is terephthalic acid or its ester-forming derivative, and isophthalic acid or its ester-forming property It is obtained by polycondensation of a derivative and 1,4-butanediol or an ester-forming derivative thereof by a generally known method. By appropriately adjusting the above isophthalic acid content, the melting point of the polybutylene terephthalate resin used in the present invention can be obtained.

  The first component polybutylene terephthalate resin used in the present invention has an intrinsic viscosity of 0.3 to 3.0 dl measured at 25 ° C. using an o-chlorophenol solvent in accordance with JIS K7367-5 (2000 version). A resin in the range of / g is preferably used. By having an intrinsic viscosity of 0.3 to 3.0 dl / g, more preferably 0.4 to 2.0 dl / g, and even more preferably 0.5 to 1.0 dl / g, it has moderate fluidity. Spinning is easy to stabilize.

  The polybutylene terephthalate-based resin of the first component used in the present invention is an antioxidant, a weather stabilizer, a light stabilizer, an antistatic agent, an antifogging agent, and the like, as long as the effects of the present invention are not impaired. Additives such as antiblocking agents, lubricants, nucleating agents, pigments, and other polymers can be added as necessary.

  Examples of the polypropylene resin, which is another second component constituting the split-type conjugate fiber in the present invention, include propylene homopolymers and copolymers of propylene and various α-olefins.

  The melting point of the second component polypropylene resin used in the present invention is preferably 130 to 170 ° C. By setting the melting point to 130 to 170 ° C., more preferably 140 to 170 ° C., and still more preferably 150 to 170 ° C., it becomes possible to obtain a spinning temperature suitable for the polybutylene terephthalate resin and a high spinning speed. But it can be spun stably.

  The melt flow rate (hereinafter sometimes referred to as MFR; ASTM D-1238 load; 2160 g, temperature; 230 ° C.) of the second component polypropylene resin used in the present invention is 1-1000 g / 10 min. It is preferably 10 to 500 g / 10 min, more preferably 20 to 200 g / 10 min. By setting the melt flow rate in the range of 1 to 1000 g / 10 min, it becomes easy to perform stable spinning, and orientation crystallization easily proceeds, so that high-strength fibers are easily obtained.

  In the second component polypropylene resin used in the present invention, the antioxidant, weathering stabilizer, light stabilizer, antistatic agent, antifogging agent, antiblocking agent which are usually used are within the range not impairing the effects of the present invention. Additives such as agents, lubricants, nucleating agents, pigments, and other polymers can be added as necessary.

  In the split-type composite fiber of the present invention, the composite ratio (mass ratio) of the first component polybutylene terephthalate resin and the second component polypropylene resin is 10 to 70% by mass: 90 to 30% by mass. By setting the composite ratio (mass ratio) of the first component and the second component to 10 to 70% by mass: 90 to 30% by mass, preferably 20 to 50% by mass: 80 to 50% by mass, sufficient resolution is achieved. Moreover, a softness | flexibility can be ensured by making the 2nd component polypropylene resin into 50 mass% or more.

  In the split composite fiber of the present invention, in the cross section perpendicular to the fiber length direction (cross section of the split composite fiber), the first component or the second component is divided into two or more by other components. This is very important. In the cross-section perpendicular to the fiber length direction, the first component or the second component is divided into two or more, more preferably four or more, and even more preferably six or more by other components, so that the split type It becomes easy to split the composite fiber, and an extra fine fiber can be obtained by splitting.

  In the split-type conjugate fiber of the present invention, it is important that at least a part of the first component and the second component are exposed on the fiber surface. When at least a part of the first component and the second component is exposed on the fiber surface, the split-type composite fiber is easily split, and an extra fine fiber can be obtained by the progress of splitting.

  As the extent that at least a part of the first component and the second component is exposed on the fiber surface, the ratio of the first component and the second component to the circumferential length in the fiber cross section before splitting is 10 to 90%. : 90 to 10% is preferable, more preferably 20 to 80%: 80 to 20%, and still more preferably 30 to 70%: 70 to 30%. By making the ratio of the length of the circumference in the fiber cross-section before splitting 10 to 90%: 90 to 10% in the first component and the second component, the split-type composite fiber is easily split, Ultra-fine fibers can be obtained by the progress of splitting.

  FIG. 1 is a schematic cross-sectional view illustrating a cross section (a cross section perpendicular to the fiber length direction) of a split composite fiber in the present invention.

  (A) of FIG. 1 is perpendicular to the fiber length direction of a split type composite (long) fiber composed of a first component containing a polybutylene terephthalate resin and a second component containing a polypropylene resin. FIG. 5 is a schematic cross-sectional view showing an example in which a region 1 made of the first component and a region 2 made of the second component are divided into eight in a cross section (transverse cross section).

  In FIG. 1 (a), a total of 16 regions, that is, a region 1 composed of eight first components and a region 2 composed of eight second components, have a part of the outer periphery thereof as described above. Share with the perimeter of.

  FIG. 1 (b) shows a hollow fiber having a hollow portion 3 in the center, and the region 1 made of the first component and the region 2 made of the second component are divided into 8 pieces each. It is the schematic cross section which showed the example divided. In FIG. 1 (b), a total of 16 regions, that is, a region 1 composed of eight first components and a region 2 composed of eight second components, are part of the outer periphery of the section. Shared with the perimeter.

  FIG. 1C is a schematic cross-sectional view showing an example in which the region 1 composed of the first component is divided into three by the region 2 composed of the second component arranged in parallel. In FIG. 1 (c), a total of five regions, a region 1 composed of three first components and a region 2 composed of two second components, have a part of the outer periphery of the above section. Shared with the perimeter.

  FIG. 1D is a schematic cross-sectional view showing an example in which the region 2 made of the second component is divided into four by the region 1 made of the first component. In FIG. 1 (d), a total of five regions, that is, a region 1 composed of one first component and a region 2 composed of four second components, have a part of the outer periphery of the above section. Shared with the perimeter.

  FIG. 1E is a schematic cross-sectional view showing an example in which the region 1 made of the first component is divided into four regions by the region 2 made of the second component. In FIG. 1 (e), a total of five regions, that is, a region 1 composed of four first components and a region 2 composed of one second component are part of the outer periphery of the above section. Shared with the perimeter.

  The split type composite fiber referred to in the present invention refers to a fiber that is composed of at least two or more components and can be split into at least two or more.

  The single fiber diameter of the split composite fiber of the present invention is preferably 13 to 33 μm. By setting the single fiber diameter to 13 to 33 μm, more preferably 13 to 24 μm, and even more preferably 13 to 18 μm, it becomes possible to stably spin and excellent uniformity when used for the constituent fibers of the nonwoven fabric.

  The split type composite fiber of the present invention can be split into fibers composed of at least one of the first component and the second component by physically applying a force with a needle punch and / or a water jet punch, In the present invention, the division is called split fiber. Part or all of the split-type composite fibers are split to form ultrafine fibers.

  The split-type conjugate fiber of the present invention can be used as a fiber constituting any fabric such as a woven fabric or a nonwoven fabric, and among them, it can be suitably used as a constituent fiber of a nonwoven fabric.

  Although the nonwoven fabric of this invention can employ | adopt any aspect of a long fiber and a short fiber, the nonwoven fabric manufactured by the spunbond method from a viewpoint that it is excellent in productivity is preferable.

  The nonwoven fabric composed of the split-type composite fibers of the present invention is split by splitting the split-type composite fibers by physically applying force with a needle punch and / or a water jet punch. It is preferable that the average fiber diameter of the single fiber (ultrafine fiber) after splitting is 1.0 to 8.0 μm. A more preferable average fiber diameter is 1.0 to 6.7 μm, and further preferably 2.8 to 5.8 μm. By setting the average fiber diameter of the single fibers (ultrafine fibers) after splitting to 1.0 to 8.0 μm, the uniformity of the nonwoven fabric tends to be improved and softened. Moreover, if the average fiber diameter is in the range of 1.0 to 8.0 μm, it is allowed to contain unbroken fibers. This is because a nonwoven fabric in which unbroken fibers are mixed is excellent in nonwoven fabric strength due to unbroken fibers or fibers in a shape in which only a part of unbroken fibers are divided.

  In the nonwoven fabric composed of ultrafine fibers after splitting according to the present invention, the tensile strength per unit weight in the MD direction of the nonwoven fabric is preferably 1.5 N / 5 cm or more. When the tensile strength of the nonwoven fabric per unit weight is 1.5 N / 5 cm or more, more preferably 1.6 N / 5 cm or more, the nonwoven fabric has a process tension at the time of production and a strength sufficient for practical use. The upper limit value of the tensile strength is preferably 10.0 N / 5 cm or less because flexibility tends to be impaired when a too high tensile strength is obtained.

  As a method of setting the tensile strength of the nonwoven fabric per unit area to 1.5 N / 5 cm or more, the present invention is excellent in spinning stability, so that the fiber is crystallized by increasing the spinning speed to improve the strength of the fiber. A method is mentioned.

  The nonwoven fabric composed of the ultrafine fibers after splitting according to the present invention preferably has a bending resistance of 60 mm or less. When the bending resistance is 60 mm or less, preferably 50 mm or less, more preferably 40 mm or less, sufficient flexibility can be obtained particularly when used as a nonwoven fabric for sanitary materials. The lower limit value of the bending resistance is preferably 10 mm or more because if the bending resistance is too low, the handleability of the nonwoven fabric may be inferior.

It is preferable that the fabric weight of the nonwoven fabric which consists of the ultrafine fiber after splitting of this invention is 10-100 g / m < ² >. By setting the basis weight to 10 g / m ² or more, more preferably 15 g / m ² or more, it is possible to obtain a nonwoven fabric having mechanical strength that can be used practically. On the other hand, when the nonwoven fabric is used for hygiene, the fabric weight is 100 g / m ² or less, more preferably 50 g / m ² or less, and even more preferably 30 g / m ² or less. .

  Next, as a preferred embodiment of the split composite fiber and the nonwoven fabric of the present invention, a method for producing a nonwoven fabric by the spunbond method will be described.

  The spunbond method melts the resin, spins it from the spinneret, and then cools and solidifies the yarn, which is pulled and drawn by an ejector and collected on a moving net to form a nonwoven web. Then, it is a manufacturing method which requires the process of integrating by thermal bonding or mechanical entanglement.

  As the shape of the spinneret and the ejector, various shapes such as a round shape and a rectangular shape can be adopted. Among these, a combination of a rectangular base and a rectangular ejector is a preferable aspect from the viewpoint that the amount of compressed air used is relatively small and the yarns are not easily fused or scratched.

  The spinning temperature in melting and spinning the resin is preferably 220 to 250 ° C, more preferably 225 to 245 ° C. By setting the spinning temperature within the above range, a stable molten state can be obtained, the cooling of the polypropylene resin can easily proceed, and excellent spinning stability can be obtained.

  The first component and the second component used in the present invention are melted and measured by separate extruders, supplied to a split-type composite spinneret, and spun as split-type composite fibers.

  Examples of the method of cooling the spun yarn of the split-type composite fiber include a method of forcing cold air to the yarn, a method of natural cooling according to the ambient temperature around the yarn, and a distance between the spinneret and the ejector. It is possible to adopt a method of adjusting the above, a method of combining them, or the like.

  The cooling conditions can be appropriately adjusted and employed in consideration of the discharge amount per single hole of the spinneret, the spinning temperature, the atmospheric temperature, and the like.

  Next, the cooled and solidified yarn is pulled and compressed by compressed air injected from the ejector.

  The spinning speed is preferably 2,600 to 6,000 m / min, more preferably 2,800 to 5,500 m / min. By setting the spinning speed to 2,600 to 6,000 m / min, stable spinning can be performed, and oriented crystallization can proceed to obtain a high-strength split composite fiber.

  Subsequently, the split type composite fibers obtained by stretching in this way are collected on a moving net to form a nonwoven web.

  Thereafter, the nonwoven web is integrated by thermal bonding and then split by needle punch and / or water jet punch, or the nonwoven web is split directly by needle punch and / or water jet punch, However, both methods are preferably employed.

  As a method of integrating by the above thermal bonding, a heat embossing roll in which engraving is performed on a pair of upper and lower roll surfaces, a roll with one roll surface being flat (smooth) and an engraving on the other roll surface Examples thereof include a method of heat bonding with various rolls such as a heat embossing roll formed of a combination with a roll and a heat calender roll formed of a combination of a pair of upper and lower flat (smooth) rolls.

  The surface temperature of the hot roll is preferably set to −100 to −30 ° C. with respect to the melting point of the lowest melting point resin (hereinafter sometimes referred to as low melting point resin) among the resins used. By setting the surface temperature of the heat roll to −100 ° C. or higher, more preferably −90 ° C. or higher, with respect to the melting point of the low-melting resin, it is possible to appropriately heat bond and maintain the nonwoven fabric form.

  Moreover, excessive heat adhesion is suppressed by setting the surface temperature of the heat roll to −30 ° C. or less, more preferably −50 ° C. or less, and still more preferably −70 ° C. or less with respect to the melting point of the low melting point resin. Fiber entanglement and splitting with a needle punch and / or water jet punch can easily proceed.

  The linear pressure of the hot embossing roll during thermal bonding is preferably 200 to 1500 N / cm. By setting the linear pressure of the roll to 200 N / cm or more, more preferably 300 N / cm or more, it is possible to appropriately heat bond and maintain the nonwoven fabric form. On the other hand, by setting the linear pressure of the roll to 1500 N / cm or less, more preferably 1000 N / cm or less, excessive thermal adhesion is suppressed, and the fiber entanglement and splitting by the subsequent needle punch and / or water jet punch are reduced. The fiber becomes easy to advance.

  Moreover, it is preferable that an embossing adhesion area ratio is 5 to 30%. By setting the bonding area to 5% or more, more preferably 10% or more, it is possible to appropriately heat-bond and maintain the nonwoven fabric form. On the other hand, by setting the bonding area to 30% or less, more preferably 20% or less, excessive thermal bonding is suppressed, and entanglement and splitting of the fiber by the subsequent needle punch and / or water jet punch can easily proceed. Become.

  The embossed adhesion area ratio here refers to the entire nonwoven fabric of the portion where the convex part of the upper roll and the convex part of the lower roll are overlapped with each other to contact the non-woven web when thermally bonded by a roll having a pair of irregularities. This is the proportion of the total. Moreover, when heat-bonding by the roll which has an unevenness | corrugation, and the flat roll, the convex part of the roll which has an unevenness | corrugation means the ratio which occupies for the whole nonwoven fabric of the part which contact | abuts a nonwoven web.

  As the shape of the engraving applied to the hot embossing roll, a circle, an ellipse, a square, a rectangle, a parallelogram, a rhombus, a regular hexagon, a regular octagon, and the like can be used.

On the other hand, when splitting a split-type composite fiber while mechanically entangled with a needle punch, the needle shape, the number of needles per unit area, and the like are appropriately selected and adjusted. In particular, the number of needles per unit area is preferably at least 100 needles / cm ² or more from the viewpoints of strength, shape retention, and splitting of the split-type conjugate fiber. Moreover, it is a preferable aspect that a silicone-based oil agent is sprayed onto the nonwoven web before needle punching to prevent the fibers from being cut by the needle and to improve the entanglement between the fibers.

  Further, when the mechanical entanglement is performed by a water jet punch, it is preferable to perform the water in a columnar flow state. In order to obtain a columnar flow, generally, a method of ejecting from a nozzle having a diameter of 0.05 to 3.0 mm at a pressure of 1 to 60 MPa is suitably used. The pressure for splitting the composite fiber while efficiently entwining and integrating the nonwoven web is preferably at least once treated with a pressure of 10 MPa or more, and more preferably 15 MPa or more.

The nonwoven fabric made of the split fiber of the present invention is subjected to a mechanical entanglement process such as a needle punch or a water jet punch, whereby the fiber moves in the sheet thickness direction and has a bulky sheet structure as compared to before the process. The bulk density of the nonwoven fabric composed of split fiber is preferably 0.10 g / cm ³ or less, more preferably 0.9 g / cm ³ or less, and even more preferably 0.8 g / cm ³ or less. . By setting the bulk density to 0.10 g / cm ³ or less, a low density and flexible sheet can be obtained. Further, the lower limit is not particularly provided, but when the bulk density is too small, the strength tends to decrease, so that it is preferably 0.01 g / cm ³ or more.

  The nonwoven fabric composed of the split composite fiber of the present invention and split from the split composite fiber is excellent in mechanical strength, uniformity and flexibility, and is used as a material for disposable diapers, sanitary products, wiping cloths, etc. It can be suitably used.

  Next, based on an Example, the split type composite fiber and nonwoven fabric of this invention are demonstrated concretely.

(1) Spinnability evaluation:
The spinning state was observed for 1 hour, and evaluated as 0 for 2 yarn breaks, 3 for 6 to 6 yarn breaks, and x for 7 or more yarn breaks.

(2) Fiber diameter after splitting of split-type composite fiber:
The obtained non-woven fabric composed of ultrafine fibers after splitting is embedded in an epoxy resin, and then cut with a microtome to obtain a sample piece. Next, a 1000 × photograph was taken with a scanning electron microscope, and the cross-sectional area of any 100 fibers was measured. The measured cross-sectional area was regarded as the cross-sectional area of the fiber having a round cross-sectional shape, and the fiber diameter was calculated by the following formula. The average value was calculated for the calculated 100 fiber diameters, and the second decimal place was rounded off to obtain the fiber diameter.
Fiber diameter (μm) = √ (4 × cross-sectional area (μm ² ) /3.14).

(3) Fabric weight of nonwoven fabric:
Based on 6.2 “mass per unit area” of JIS L1913 (2010), three nonwoven fabric test pieces of 20 cm × 25 cm were collected per 1 m width of the sample, and each mass (g) in the standard state was measured. The average value was expressed in terms of mass per 1 m ² (g / m ² ).

(4) MD tensile strength and non-woven fabric tensile strength:
According to JIS L1913 (2010) 6.3.1, sample size 5cm x 30cm, grip interval 20cm, tensile speed 10cm / min. The strength was MD tensile strength (N / 5 cm), and the average value was calculated by rounding off the second decimal place. Subsequently, the calculated MD tensile strength (N / 5 cm) is rounded off from the basis weight (g / m ² ) obtained in (3) above to the second decimal place from the following formula, and the tensile strength per unit basis weight Was calculated.
MD tensile strength per unit weight = MD tensile strength (N / 5 cm) / weight per unit area (g / m ² ).

(5) Bending softness of nonwoven fabric:
In accordance with 6.7.3 of JIS L1913 (2010), five test pieces each having a width of 25 mm × 150 mm were taken in the MD direction and the CD direction, and the test pieces were placed on a horizontal table having a 45 ° slope. The short side of was placed on the scale baseline. The test piece was manually slid in the direction of the slope, and when the central point of one end of the test piece was in contact with the slope, the moving length of the other end position was read with a scale. Measurements were made on the back and front of each of the MD direction and the CD direction, and the average values in the MD direction and the CD direction were calculated.

[Example 1]
“Toraycon” (registered trademark) 1100E (polybutylene terephthalate / isophthalate copolymer) manufactured by Toray Industries, Inc. having an intrinsic viscosity of 0.80 dl / g and a melting point of 208 ° C. as a first component, and an MFR of 35 g as a second component / 10 minutes (load: 2160 g, temperature: 190 ° C.), a polypropylene resin having a melting point of 160 ° C. is melted with different extruders, and weighed so that the mass ratio of each component is 50:50, and spinning. A split-type composite fiber having a cross-sectional shape in which the two components shown in FIG. Spun out. The spun split type composite fiber was passed through an ejector and sprayed from the ejector at a spinning speed of 3700 m / min. The yarn was pulled, stretched, collected on a moving net, and formed into a nonwoven web. Subsequently, a linear pressure of 200 N / cm and a thermal bonding temperature of 80 are formed using a pair of upper and lower embossed rolls composed of an upper roll engraved with a metal polka dot pattern and a metal lower flat roll. Using a nozzle with a hole diameter of 0.1 mm for thermal bonding treatment at 0 ° C. and then separating the fibers, the distance from the nozzle to the nonwoven fabric is 25 mm, the water pressure of 100 MPa, the line speed of 5 m / min, the nonwoven fabric surface and back surface Were subjected to water jet punching twice to prepare a split fiber nonwoven fabric having a basis weight of 30 g / m ² . The obtained nonwoven fabric was evaluated by measuring the fiber diameter after splitting, the basis weight, the tensile strength per basis weight, and the bending resistance. The results are shown in Table 1.

[Comparative Example 1]
Spinning was performed in the same manner as in Example 1 except that the first component was polyethylene terephthalate having an intrinsic viscosity of 0.64 dl / g and a melting point of 263 ° C., and the spinning temperature was 295 ° C. Many yarn breaks occurred due to the fusion of the two, and a nonwoven web could not be obtained.

[Comparative Example 2]
The first component was “Toraycon” (registered trademark) 1100S (polybutylene terephthalate polymer) manufactured by Toray Industries, Inc. having an intrinsic viscosity of 0.85 dl / g and a melting point of 227 ° C., and the spinning temperature was 260 ° C. When spinning was performed in the same manner as in Example 1, the yarn breakage was scattered and the spinning was not stable, and the nonwoven web was collected at a spinning speed of 2300 m / min. Thereafter, as in Example 1, thermal bonding and water jet punching were performed. Processing was carried out to prepare a split fiber nonwoven fabric with a basis weight of 30 g / m ² . The obtained nonwoven fabric was evaluated by measuring the fiber diameter after splitting, the basis weight, the tensile strength per basis weight, and the bending resistance. The results are shown in Table 1.

  As is clear from Table 1, Example 1 has good spinnability and can be stretched at a high spinning speed, and is excellent in splitting properties by a combination of incompatible resins, and excellent in strength and flexibility of the nonwoven fabric. It was.

  On the other hand, in Comparative Example 1, the sheet (nonwoven fabric) could not be collected due to poor spinning, and in Comparative Example 2, the spinning speed was not increased because the spinning was not stable, and the strength of the nonwoven fabric was inferior.

1: Region composed of the first component 2: Region composed of the second component 3: Cavity

Claims (3)

  It consists of a first component containing a polybutylene terephthalate resin having a melting point of 180 to 220 ° C. and a second component containing a polypropylene resin, and the composite ratio is 10 to 70% by mass: 90 to 30% by mass. A certain fiber, wherein the first component or the second component is divided into two or more when viewed from a cross section of the fiber, and at least a part of the first component and the second component is exposed on the fiber surface. A split type composite fiber characterized by   The split type composite fiber constituting the nonwoven fabric comprising the split type composite fiber according to claim 1 is split, and the average fiber diameter of the split single fiber is 1.0 to 8.0 μm. Non-woven fabric.   The non-woven fabric according to claim 2, wherein the non-woven fabric comprising split-type composite fibers is manufactured by a spunbond method.

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