JP5334583B2 - Split composite long fiber, non-woven fabric composed of split composite long fiber, and split fiber non-woven fabric - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a split composite long fiber excellent in splitting property made of an olefin polymer suitable for sanitary materials, filters, wipers, battery separators, and the like, a non-woven fabric consisting of split composite long fibers, and a split fiber non-woven fabric.

  Nonwoven fabrics made of ultrafine fibers are excellent in flexibility, texture and the like, and are widely used as materials for clothing, disposable diapers, sanitary goods, wiping cloths and the like. In recent years, it is expected to be used in a clean room because of its excellent wiping performance.

  As one of the methods for obtaining ultrafine fibers, a multi-component polymer is spun into a split-type composite fiber, and the resulting split-type composite fiber is utilized by physical stress, differential shrinkage of resin to chemicals, etc. And the method of dividing | segmenting into many fibers and obtaining an ultrafine fiber is used. In general, polymers used for the split type composite fibers are easily peeled, that is, incompatible polyester and polyolefin, polyester and polyamide, polyamide and polyolefin, and the like.

  Splitting composite fibers made of the same kind of polymer are inferior to the combination of polyester and polyolefin, so there are various methods for improving the splitting ability of splitting composite fibers made of a propylene polymer and an ethylene polymer. Proposed. For example, a method in which a polypropylene-based resin and a polyethylene-based resin having different MFR ratios are made into split-type composite fibers having a bent cross section (Patent Document 1; Japanese Patent Laid-Open No. 2000-328348), and a polypropylene-based resin having a molecular weight distribution of at least 5 A method of using a polyethylene-based resin, melt spinning using a split type composite nozzle having a hollow center in the cross section, and drawing into a split type composite fiber by multistage drawing 5 times or more (Patent Document 2; No. 220740) has been proposed.

  However, in order to improve the splitting property, a special nozzle is required or multi-stage drawing is required, and while the spun composite long fiber is cooled by a cooling fluid, the long fiber is tensioned with the fluid to be thinned. In the method, a nonwoven fabric composed of split-type composite continuous fibers having excellent splitting properties has not been obtained.

JP 2000-328348 A JP 2002-220740 A

  In the present invention, as a result of various studies for the purpose of improving the splitting property of a split type composite fiber composed of a propylene polymer and an ethylene polymer, (A) as a propylene polymer at a load of 2160 g at 230 ° C. It has been found that by using (B) a high-pressure method low-density polyethylene as the (A) propylene polymer and ethylene polymer having an MFR of 40 g / 10 min or more, the resolution can be improved.

  The present invention uses (A) a propylene polymer having a load of 2160 g and an MFR at 230 ° C. of 40 g / 10 min or more and (B) a high-pressure low-density polyethylene, and (A) a propylene polymer part and (B ) Provided are split-type composite long fibers in contact with high-pressure method low-density polyethylene parts, a non-woven fabric made of such split-type composite long fibers, and a split-fiber non-woven fabric formed by dividing the non-woven fabric.

  In the present invention, (A) a propylene polymer having a load of 2160 g and an MFR at 230 ° C. of 40 g / 10 min or more and (B) a high-pressure low-density polyethylene are discharged from a spinneret having a composite spinning nozzle, The composite long fiber in which the spun (A) propylene polymer portion and the (B) high-pressure method low-density polyethylene portion are in contact with each other is cooled by a cooling fluid, and tension is applied to the long fiber to reduce the length. (A) A method for producing a non-woven fabric composed of split-type composite continuous fibers and a method for producing a split-fiber non-woven fabric, characterized in that after propylene-based polymer portion is oriented and crystallized, it is collected and deposited on a collecting belt. Is to provide.

  The split-type long fibers of the present invention are excellent in splitting properties, and the resulting nonwoven fabric is made of an olefin polymer, so that it is lightweight and excellent in water resistance and flexibility.

FIG. 1 is a schematic view showing an example of a cross section of a composite long fiber according to the present invention. The four forms (a) to (d) were listed. (E) is an example of the cross-sectional form after a division | segmentation process. In the figure, the white and black portions represent the resins to be combined.

(A) Propylene Polymer The (A) propylene polymer according to the split composite long fiber of the present invention has a melt flow rate (MFR; ASTM D-1238 load; 2160 g , temperature; 230 ° C.), and an MFR of 40 g. / 10 minutes or more, preferably 50 to 500 g / 10 minutes, more preferably 55 to 100 g / 10 minutes.

When the (A) propylene-based polymer having an MFR of less than 40 g / 10 minutes is used, the resulting split-type long fibers are inferior in splitting property.
Further, the ratio Mw / Mn of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the poly (A) propylene-based polymer is usually 1.5 to less than 5.0, and the spinnability is good. And 1.5-3.5 are preferable at the point from which the composite fiber which is especially excellent in fiber strength is obtained. In the present invention, good spinnability means that yarn breakage does not occur during discharge from the spinning nozzle and during drawing, and filament fusion does not occur. When Mw / Mn is 5.0 or more, there are many high molecular weight components, so yarn breakage is likely to occur, and when Mw / Mn is 1.5 or less, filament fusion is likely to occur due to crystallization delay during stretching. There is a problem. In the present invention, Mw and Mn can be measured by a known method by GPC (gel permeation chromatography).

  The propylene-based polymer (A) according to the present invention is a propylene homopolymer or carbon such as propylene and a small amount of ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc. Examples thereof include copolymers with α-olefins of several 2 to 10. The (A) propylene polymer is preferably a polymer having a melting point (Tm) of 155 ° C. or higher, more preferably 160 ° C. or higher.

  The (A) propylene polymer according to the present invention includes an antioxidant, a weather resistance stabilizer, a light resistance stabilizer, an antistatic agent, an antifogging agent, and an antiblocking agent that are usually used as long as the object of the present invention is not impaired. Additives such as lubricants, nucleating agents, pigments, and other polymers can be blended as necessary.

(B) High-pressure low-density polyethylene (B) The high-pressure low-density polyethylene according to the split composite long fiber of the present invention is a so-called polymer obtained by radical polymerization of ethylene under high pressure. It is a copolymer or a copolymer of ethylene and a small amount of vinyl acetate. The (B) high-pressure method low-density polyethylene is an ethylene / α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 10 carbon atoms under a low pressure using a Ziegler catalyst, a metallocene catalyst or the like. Radical polymerization of ethylene using so-called linear low density polyethylene (LLDPE) and Ziegler catalyst (low pressure 10-20 kg / cm ² ) or Philips catalyst or standard catalyst (medium pressure 30-100 kg / cm ² ). It is a polymer different from so-called high density polyethylene (HDPE; density 0.950 to 0.970 g / cm ³ ) obtained in the above manner.

The melt flow rate (MFR; ASTM D-1238 load; 2160 g , temperature: 190 ° C.) of the (B) high-pressure low-density polyethylene according to the present invention is not particularly limited as long as it can be melt-spun, but usually 1 to 1000 g. / 10 minutes, preferably 10 to 500 g / 10 minutes, more preferably 20 to 100 g / 10 minutes.

The melting point (Tm) of the (B) high-pressure method low density polyethylene according to the present invention is preferably in the range of 90 to 110 ° C., more preferably 95 to 110 ° C., and the density is preferably 0.900 to 0.935 g / cm ³ , more preferably in the range of 0.905 to 0.925 g / cm ³ .

  The (B) high-pressure method low-density polyethylene according to the present invention includes an antioxidant, a weather-resistant stabilizer, a light-resistant stabilizer, an anti-static agent, an anti-fogging agent, and an anti-blocking agent, as long as the object of the invention is not impaired. Additives such as agents, lubricants, nucleating agents, pigments, or other polymers can be blended as necessary.

Split type composite long fiber The split type composite long fiber of the present invention comprises the (A) propylene polymer and the (B) high-pressure low-density polyethylene, and (A) the propylene polymer part and (B). It is a split-type composite long fiber in which high-pressure method low-density polyethylene parts are in contact with each other.

  (A) When the propylene-based polymer is (A) a propylene-based polymer having a load of 2160 g and an MFR at 230 ° C. of less than 40 g / 10 minutes, the resulting split-type composite continuous fiber is inferior in splitting property, (B) When the linear low-density polyethylene is used instead of the high-pressure method low-density polyethylene, the obtained split-type composite continuous fiber is inferior in splittability.

The shape (cross section) of the split-type composite long fiber is not particularly limited as long as (A) the propylene-based polymer portion and (B) the high-pressure method low-density polyethylene portion are in contact with each other, [FIG. 1 (e)], etc., but from the viewpoint of ensuring good spinnability, a so-called perfect circle shape (FIG. 1 (a)), which is a curve composed of a set of points having the same distance from the center. And (b)) are preferred.
The split-type composite long fibers of the present invention have the same orientation pattern, and the degree of orientation is at least 0.80, preferably 0.82 or more, and the propylene-based polymer portion and the ethylene-based polymer portion are in contact with each other. It is a split type composite long fiber. Here, the orientation mode indicates a tendency in which the structural elements in the molecular chain are selectively oriented with respect to the fiber axis as a whole. For example, a high degree of c-axis orientation means that the crystal lattice has a high degree of orientation. The c axis is selectively oriented in the fiber axis direction, indicating a high ratio.
The same orientation pattern and higher degree of orientation are preferred because both components are crystallized at the same time or because the splitting property is excellent.

In the split-type composite continuous fiber of the present invention, the orientation degree of the main orientation mode of the ethylene polymer is preferably at least 0.70, more preferably 0.75 or more.
The degree of orientation of the present invention is determined using a wide-angle X-ray diffractometer (RINT2550, manufactured by Rigaku Corporation, attached device: fiber sample stage, X-ray source: CuKα, output: 40 kV 370 mA, detector: scintillation counter). An azimuth distribution curve (X) obtained by measuring the azimuth distribution intensity of crystal plane peaks [polypropylene polymer: (110) plane, polyethylene polymer: (200) plane], arranged in a direction and fixed to a sample holder. In the line interference diagram), the degree of orientation in the fiber axis direction is calculated from the half-value width (α) of the peak according to the following formula and evaluated. In addition, in the orientation degree calculated | required by the following formula, when it is less than 0.8, it judges that orientation is very low and makes it non-orientation.
Orientation degree (F) = (180 ° −α) / 180 ° (α is the peak half-value width in the azimuth distribution curve)

  The fineness of the split-type composite continuous fiber of the present invention is usually preferably 6 denier or less. If it is 6 deniers or less, the fineness after a split fiber process can be made thin, and since it is excellent in wiping property and a softness | flexibility, it is preferable. Further, the number of divisions of the propylene polymer part and the ethylene polymer part forming the split-type composite long fiber is not particularly limited as long as it does not impair the splittability, but usually 4 to 48 splits, preferably Is in the range of 4 to 24 divisions. By setting the fineness of the split-type composite long fiber and the splitting of the composite fiber in such a range, the fineness of the split fiber obtained by dividing the nonwoven fabric made of the composite fiber is 0.001 to 2.00 denier, preferably 0.001. It can be in the range of ~ 0.5 denier.

Nonwoven fabric made of splittable conjugated filaments of the nonwoven fabric present invention comprising a splittable conjugated filaments are made from the splittable conjugated filaments, typically having a basis weight 3~200g / m ^2, preferably from 10 to 150 g / m ² Is in range. Moreover, the nonwoven fabric of this invention heat-seals a split-type composite long fiber group by methods, such as an embossing roll and ultrasonic fusion | fusion, as needed. The area (embossed area ratio) in the case of heat-sealing can be appropriately selected according to the use, but is preferably 5 to 30%.

Split fiber nonwoven fabric The split fiber nonwoven fabric of the present invention comprises (A) a propylene-based polymer portion and (B) a high-pressure method low-density polyethylene portion that form a composite fiber by applying stress to the nonwoven fabric composed of the split-type composite long fibers. The basis weight is usually 3 to 200 g / m ² , preferably 10 to 150 g / m ² .

  The fineness of the split fibers forming the split fiber nonwoven fabric of the present invention is usually in the range of 0.001 to 2.0 denier, preferably 0.001 to 0.5 denier.

  Examples of the stress applied to the nonwoven fabric composed of split-type composite long fibers include various known methods, for example, a method of applying a liquid such as water at a high pressure, a so-called high-pressure water flow method (water jet method), and a gear drawing machine.

  When a high-pressure water flow is applied to a nonwoven fabric composed of split-type composite long fibers that are deposited, in order to promote entanglement and the like, for example, before the split splitting and entanglement application step by high-pressure liquid flow, It is preferred to replace the air present between the yarns with water. Specifically, water may be applied to the web.

  A high-pressure liquid flow can be obtained by injecting liquid through a nozzle hole and increasing the pressure with a high-pressure pump. As a nozzle hole, a hole diameter is 0.05-1.0 mm normally, More preferably, it exists in the range of 0.1-0.5 mm. The pressure of the high-pressure liquid flow is usually in the range of 5 to 400 MPa, preferably 50 to 300 MPa. In addition, water or warm water is applied as the liquid for ease of handling, and pure water having a specific resistance value of 10 MΩ · cm or more, more preferably 15 MΩ · cm or more, is used with a known water quality measuring apparatus.

  The distance between the nozzle hole and the nonwoven fabric is preferably about 1 to 15 cm. When this distance exceeds 15 cm, the energy which a liquid gives to a nonwoven fabric will fall, and it will become the tendency for the effect of splitting or entanglement to fall. Moreover, when it becomes less than 1 cm, the formation of the nonwoven fabric tends to be disturbed.

  Generally, the nozzle holes of the high-pressure liquid stream are arranged in a row in a direction intersecting with the traveling direction of the nonwoven fabric. In the case of single-sided processing, in order to obtain uniform split splitting and tight entanglement coupling, it is preferable to carry out the injection holes in two or more rows, preferably three or more rows. The pressure of the high-pressure liquid stream is preferably low on the front side and high on the rear side in order to make the formation uniform.

  Furthermore, the appearance pattern of the split fiber nonwoven fabric according to the present invention, the so-called pattern, can be changed by appropriately selecting the pattern of the screen belt used during the treatment of the high-pressure liquid flow.

  The split fiber nonwoven fabric subjected to split splitting treatment with a high-pressure liquid flow is then dried and heat-treated after excess moisture is removed by mechanical squeezing into a final product. The heat treatment temperature time can be selected not only to remove moisture but also to allow moderate shrinkage and promotion of crystallization. The heat treatment may be a dry heat treatment or a wet heat treatment.

Method for Producing Split Type Composite Long Fiber and Nonwoven Fabric The nonwoven fabric comprising the split type composite long fiber and the split type composite long fiber of the present invention uses the (A) propylene-based polymer and (B) high-pressure method low-density polyethylene. Although it can be obtained by a known melt spinning production method, the spunbond method is preferred in that a filament having good productivity and excellent splitting properties can be obtained.

  A spunbond method will be described as an example as a method for producing the split composite fiber nonwoven fabric of the present invention. The (A) propylene polymer and (B) high-pressure low-density polyethylene are separately melted with an extruder or the like, and each melt is exemplified in FIGS. 1 (a) to 1 (e). And (A) a propylene-based polymer portion and (B) a low-pressure method low density by discharging from a spinneret having a composite spinning nozzle that has a hollow, radial, parallel or parallel, or arc-shaped cross-sectional structure. Spinning split-type composite long fibers whose polyethylene parts are in contact with each other. The spun split-type composite long fibers are cooled by a cooling fluid, and further, tension is applied to the long fibers by drawn air to obtain a predetermined fineness, which is then collected on a collecting belt and deposited to a predetermined thickness. . Next, heat embossing is performed as necessary by heat fusion using a heat embossing roll. In the case of heat fusion with a hot embossing roll, the embossing area ratio of the embossing roll is appropriately determined, but is usually preferably 5 to 30%.

  At this time, by appropriately selecting a molding temperature, a spinning speed, and a cooling air temperature within a range in which spinnability is good, (A) a propylene-based polymer part, preferably (A) a propylene-based polymer part, and (B) a high-pressure method. It is necessary to crystallize the low density polyethylene part within the above range.

Method for Producing Split Fiber Nonwoven Fabric The method for producing the split fiber nonwoven fabric of the present invention comprises the steps of (A) propylene-based polymer portion and (B) high-pressure method using the above-mentioned various types of nonwoven fabrics composed of split-type composite continuous fibers. The density polyethylene part is divided.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

  In addition, the physical-property value etc. in an Example and a comparative example were measured with the following method.

(1) Dividing ratio The obtained divided fiber nonwoven fabric is embedded in an epoxy resin, and then cut with a microtome to obtain a sample piece. When this is observed with an electron microscope (S-3500N scanning electron microscope manufactured by Hitachi, Ltd.) and the number of segments of the divided fiber cross section observed from the obtained cross-sectional image is 1, the division ratio is 100%. When the observed number of segments in the cross section of the split fibers was two or more, the split ratio was calculated by the following formula. This was observed for 50 fibers, and the average value was taken as the split ratio of the split fiber nonwoven fabric.

Dividing ratio [%] = (total number of segments−number of observed segments of divided fibers) / total number of segments × 100
Here, the total number of segments refers to the total number of segments forming the filament cross section of the split composite fiber. For example, in the case of a split type composite fiber having a filament cross section as shown in FIGS. 1 (a), (b) and (d), the total number of segments is 8.

  For example, when a split fiber cross section as shown in FIG. 1 (e) is observed in a filament having a total number of segments of 8 as shown in FIG. 1 (a), the number of segments of the observed split fiber cross section is set to 3, Further, the division ratio is 62.5%.

(2) Fineness The obtained split fiber nonwoven fabric is embedded in an epoxy resin, and then cut with a microtome to obtain a sample piece. Next, the sample was observed with an electron microscope (S-3500N scanning electron microscope manufactured by Hitachi, Ltd.), 30 undivided filaments were selected from the obtained cross-sectional image, and the cross-sectional area was calculated. The fineness of the undivided filament was determined, and the fineness of the divided fiber was calculated by the following formula using the division ratio.
Fineness of split fibers = unsplit filament fineness / (total number of segments x split ratio / 100)

(3) Texture The touch is evaluated by 10 evaluators, and the evaluation results are shown according to the following criteria.

◎: When 10 people out of 10 feel that the touch is good,
○: If there are 9 to 7 people out of 10
Δ: When 6 to 3 out of 10 people feel that the touch is good,
X: When the number of people who feel that the touch is good is 2 or less out of 10 people.

(4) Flexibility (45 ° cantilever method)
In accordance with JIS L1096 (6.19.1 A method paragraph), the temperature is 20 ± 2 ° C. and the humidity is 65 ± 2% in a temperature-controlled room specified in JIS Z 8703 (standard state of test place). Five test pieces are collected in each of the flow direction (MD) and the horizontal direction (CD), and the short side of the test piece is placed on a smooth horizontal table with a 45 ° slope so that the short side of the test piece matches the scale base line. Next, the test piece is manually slid gently in the direction of the slope, and when the central point of one end of the test piece comes into contact with the slope, the moving length of the other end is read on the scale. Bending / softening (bending / softening) is indicated by the length (mm) of the test piece moved, measured for each of the five front and back sides, and expressed as an average value in each of the flow direction (MD) and the transverse direction (CD).

  It is judged that the lower the bending resistance is, the more flexible the nonwoven fabric is. Generally, when the value of the bending resistance is less than 25 mm in both the flow direction (MD) and the transverse direction (CD), it is determined that the flexibility is good. However, since the required flexibility varies depending on the purpose of use, it is not necessarily limited to this value.

(5) Tensile strength In accordance with JIS L1906 (6.12.1 A method), the flow direction in a temperature-controlled room with a temperature of 20 ± 2 ° C and a humidity of 65 ± 2% as defined in JIS Z8703 (standard condition of test place) As the tensile strength of (MD), three nonwoven fabric test pieces of 25 cm in the flow direction (MD) and 2.5 cm in the transverse direction (CD) were collected, and the tensile strength in the transverse direction (CD) was taken as the flow direction (MD). 3 pieces of non-woven fabric test pieces of 2.5 cm in the transverse direction (CD) and 25 cm in the transverse direction (CD), and a tensile tester (Instron Model 5564 manufactured by Instron Japan Ltd.) under the conditions of 200 mm between chucks and a pulling speed of 200 mm / min. The tensile test was performed, the tensile load was measured about three test pieces, and the average value of those maximum values was made into the tensile strength.

(6) Air permeability In accordance with JIS L 1096 (Breathability A method), 20 test pieces of 100 x 100 mm were collected from the sample length direction and used as a Frazier type tester (Daiei Scientific Instruments Seisakusho AT-360S). The average value of the measurement results was taken as the air permeability.

The lower the air permeability, the higher the splitting ability, so it can be determined that the ultrafine fibers are uniformly present throughout the nonwoven fabric.
[Example 1]
(A) Propylene polymer part (A) Propylene polymer (density 0.910 g / cm ³ , melting point 157 ° C., Mw / Mn 2.75) with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min as a propylene polymer part, (B) As a high-pressure method low-density polyethylene part, a load of 2160 g and a 190 ° C. MFR of 20 g / 10 minutes are used. (B) High-pressure method low-density polyethylene [density 0.919 g / cm ³ ] Melted at 0 ° C. Using a split type composite fiber spinning die having a total number of segments of 16 in the cross-sectional shape as shown in FIG. 1A, the weight ratio of (A) propylene-based polymer part to (B) high-pressure method low-density polyethylene part is 50. / 50 split-type composite long fibers were spun by a so-called spunbond method at a yarn speed of 2500 m / min and deposited on a collection belt. Next, a nozzle having a hole diameter of 0.11 mm is used to divide the fiber, the distance from the nozzle to the nonwoven fabric is 10 cm, the first-stage water pressure is 60 kgf / cm ² at the line speed of 5 m / min, and the second-stage water pressure is 100 kgf / in cm ^2, 3-stage water pressure 100 kgf / cm ^2, 4-stage pressure 100 kgf / cm ² each four times on the front and back surfaces of the nonwoven fabric is subjected to a total of eight water jet machining, basis weight 50 g / m ^Two split fiber nonwoven fabrics were prepared. About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Example 2]
(A) Propylene polymer part (A) Propylene polymer (density 0.910 g / cm ³ , melting point 157 ° C., Mw / Mn 2.75) with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min as a propylene polymer part, (B) High pressure method low density polyethylene part (B) High pressure method low density polyethylene (density 0.916 g / cm ³ ) with a load of 2160 g and 190 ° C. MFR of 35 g / 10 min. Using a split type composite fiber spinning die having a total number of segments of 16 in a cross-sectional shape as shown in FIG. 1 (a), melted at 210 ° C., (A) a propylene-based polymer part and (B) a high pressure method A split type composite continuous fiber having a density ratio of 50/50 in the density polyethylene part is spun by a so-called spunbond method at a yarn speed of 2500 m / min, deposited on a collecting belt, In order to divide, using a nozzle with a hole diameter of 0.11 mm, the distance from the nozzle to the nonwoven fabric is 10 cm, the first stage water pressure is 60 kgf / cm ² at the line speed of 5 m / min, the second stage water pressure is 100 kgf / cm ² , 3-stage water pressure 100 kgf / cm ^2, 4-stage pressure 100 kgf / cm ² at each four times on the front and back surfaces of the nonwoven fabric, a total of eight for a water jet cutting, basis weight split fibers of 50 g / m ² A nonwoven fabric was prepared. About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Example 3]
(A) Propylene polymer part with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min. (A) Propylene polymer [density 0.910 g / cm ³ , melting point 161.7 ° C., Mw / Mn 3.40 (B) High pressure method low density polyethylene part (B) High pressure method low density polyethylene (density 0.916 g / cm ³ ) with a load of 2160 g and 190 ° C. MFR of 35 g / 10 min. (A) Propylene polymer part and (B) high pressure using a split type composite fiber spinning die having a total molding number of 16 in the cross-sectional shape as shown in FIG. A split type composite continuous fiber having a weight ratio of a low density polyethylene part of 50/50 is spun by a so-called spunbond method at a yarn speed of 2500 m / min, deposited on a collecting belt, and then a fiber. In order to divide the fibers, a nozzle having a hole diameter of 0.11 mm is used, the distance from the nozzle to the nonwoven fabric is 10 cm, the first-stage water pressure is 60 kgf / cm ² at the line speed of 5 m / min, and the second-stage water pressure is 100 kgf / cm ^2. The water pressure of the third stage is 100 kgf / cm ² and the water pressure of the fourth stage is 100 kgf / cm ^2. The surface and the back surface of the nonwoven fabric are each subjected to water jet processing four times, a total of eight times, and the basis weight is 50 g / m ² . A split fiber nonwoven fabric was produced. About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Comparative Example 1]
(A) Propylene polymer part (A) Propylene polymer (density 0.910 g / cm ³ , melting point 157 ° C., Mw / Mn 2.75) with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min as a propylene polymer part, As the high-density polyethylene part, high-density polyethylene (density: 0.972 g / cm ³ ) having a load of 2160 g and an MFR of 190 ° C. of 16 g / 10 min was melted at 240 ° C. in each separate extruder molding temperature. (a) Split type composite length in which the weight ratio of the propylene polymer part to the high density polyethylene part is 50/50 using a split type composite fiber spinning die having a total number of segments of 16 in the cross-sectional shape as in a) The fiber is spun by a so-called spunbond method at a yarn speed of 2500 m / min, is deposited on a collecting belt, and then has a pore diameter of 0.11 mm in order to divide the fiber. The distance by using the nozzle from the nozzle to a nonwoven fabric as 10 cm, with in the first stage pressure 60kgf / cm ^{2, 2} stage pressure 100 kgf / cm ² line speed 5 m / min, the 3-stage water pressure 100 kgf / cm ² A total of 8 water jets were applied to the front and back surfaces of the nonwoven fabric 4 times at a water pressure of 100 kgf / cm ² in the 4th stage to produce a split fiber nonwoven fabric with a basis weight of 50 g / m ² . About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Comparative Example 2]
(A) Propylene polymer part with a load of 2160 g and an MFR of 230 ° C. of 30 g / 10 min. (A) Propylene polymer [density 0.910 g / cm ³ , melting point 165.4 ° C., Mw / Mn 6.79] The high-density polyethylene part is made of high-density polyethylene (density 0.972 g / cm ³ ) with a load of 2160 g and a 190 ° C. MFR of 16 g / 10 min. A split type composite fiber spinning die having a total number of segments of 16 in the cross-sectional shape as in 1 (a) is used. (A) A split type in which the weight ratio of the propylene-based polymer part to the high-density polyethylene part is 50/50. A composite long fiber is spun by a so-called spunbond method at a yarn speed of 2500 m / min, is deposited on a collecting belt, and then has a pore diameter of 0.11 m in order to divide the fiber. The distance from the nozzle by using the nozzle to a nonwoven fabric as a 10 cm, 1 in stage pressure 60kgf / cm ^{2, 2} stage pressure 100 kgf / cm ² at a line speed of 5 m / min, the 3-stage water pressure 100 kgf / cm ^{2 A} total of 8 times of water jet processing was performed on the front and back surfaces of the nonwoven fabric at a water pressure of 100 kgf / cm ² at the fourth stage for a total of 8 times to produce a split fiber nonwoven fabric with a basis weight of 50 g / m ² . About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Comparative Example 3]
(A) (A) propylene polymer having a load of 2160 g and an MFR of 230 ° C. of 13 g / 10 min as the propylene polymer part [density 0.910 g / cm ³ , melting point 165.4 ° C., Mw / Mn 10.97 ] As the high-density polyethylene part, high-density polyethylene (density 0.972 g / cm ³ ) having a load of 2160 g and 190 ° C. MFR of 16 g / 10 minutes was melted at 240 ° C., respectively. A split type composite fiber spinning die having a total number of segments of 16 in the cross-sectional shape as in 1 (a) is used. (A) A split type in which the weight ratio of the propylene-based polymer part to the high-density polyethylene part is 50/50. A composite long fiber is spun by a so-called spunbond method at a yarn speed of 2500 m / min, is deposited on a collecting belt, and then has a pore diameter of φ0.11 to divide the fiber. Use nozzles m as 10cm distance from the nozzles to the non-woven fabric, with in the first stage pressure 60 kgf / cm ^2, 2 stage pressure 100 kgf / cm ² line speed 5 m / min, the 3-stage water pressure 100 kgf / cm ^2, 4-stage pressure 100 kgf / cm ² each four times on the front and back surfaces of the nonwoven fabric is subjected to a total of eight water jet machining, basis weight was produced of the split fiber nonwoven fabric 50 g / m ^2. About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Comparative Example 4]
(A) Propylene-based polymer part (A) propylene-based polymer [density 0.910 g / cm ³ , melting point 157 ° C., Mw / Mn 2.80] with a load of 2160 g and an MFR of 230 ° C. of 30 g / 10 min. (B) High pressure method low density polyethylene part (B) High pressure method low density polyethylene (density 0.919 g / cm ³ ) using a load of 2160 g and 190 ° C. MFR of 20 g / 10 min. Is melted at 210 ° C., and a split type composite fiber spinning die having a total number of segments of 16 in the cross-sectional shape as shown in FIG. 1A is used. (A) Propylene-based polymer part and (B) Low pressure method high density A split-type composite continuous fiber having a polyethylene part weight ratio of 50/50 is spun by a so-called spunbond method at a yarn speed of 2500 m / min, deposited on a collecting belt, and then divided into fibers. In order to divide, using a nozzle with a hole diameter of 0.11 mm, the distance from the nozzle to the nonwoven fabric is 10 cm, the first stage water pressure is 60 kgf / cm ² at the line speed of 5 m / min, the second stage water pressure is 100 kgf / cm ² , 3-stage water pressure 100 kgf / cm ^2, 4-stage pressure 100 kgf / cm ² at each four times on the front and back surfaces of the nonwoven fabric, a total of eight for a water jet cutting, basis weight split fibers of 50 g / m ² A nonwoven fabric was prepared. About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Comparative Example 5]
(A) Propylene polymer part (A) Propylene polymer (density 0.910 g / cm ³ , melting point 157 ° C., Mw / Mn 2.75) with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min as a propylene polymer part, As the high-density polyethylene part, high-density polyethylene (density 0.95 g / cm ³ ) with a load of 2160 g and a 190 ° C. MFR of 30 g / 10 min was melted at 210 ° C. in a separate extruder molding temperature. division section using the splittable conjugate fiber spinning spinneret total segment is 16 in form (a) propylene-based polymer unit and (B) weight ratio of the high-density polyethylene portion as a) is 50/50 Type composite continuous fiber is spun by a so-called spunbond method at a yarn speed of 2500 m / min, is deposited on a collecting belt, and then has a pore diameter of 0.11 m for fiber splitting. The distance from the nozzle by using the nozzle to a nonwoven fabric as a 10 cm, 1 in stage pressure 60kgf / cm ^{2, 2} stage pressure 100 kgf / cm ² at a line speed of 5 m / min, the 3-stage water pressure 100 kgf / cm ^{2 A} total of 8 times of water jet processing was performed on the front and back surfaces of the nonwoven fabric at a water pressure of 100 kgf / cm ² at the fourth stage for a total of 8 times to produce a split fiber nonwoven fabric with a basis weight of 50 g / m ² . About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Comparative Example 6]
(A) Propylene polymer part (A) Propylene polymer (density 0.910 g / cm ³ , melting point 157 ° C., Mw / Mn 2.75) with a load of 2160 g and an MFR of 230 ° C. of 60 g / 10 min as a propylene polymer part, As the polyethylene part, a linear low density polyethylene (density 0.915 g / cm ³ ) having a load of 2160 g and an MFR of 190 ° C. of 15 g / 10 min was melted at 210 ° C. in a separate extruder molding temperature. Using a split type composite fiber spinning die having a total number of segments of 16 in the cross-sectional shape as in (a), a split type in which the weight ratio of (A) propylene polymer part and (B) polyethylene part is 50/50 A composite long fiber is spun by a so-called spunbond method at a yarn speed of 2500 m / min, is deposited on a collecting belt, and then has a pore diameter of 0.11 mm to divide the fiber. The distance by using the nozzle from the nozzle to a nonwoven fabric as 10 cm, with in the first stage pressure 60kgf / cm ^{2, 2} stage pressure 100 kgf / cm ² line speed 5 m / min, the 3-stage water pressure 100 kgf / cm ² A total of 8 water jets were applied to the front and back surfaces of the nonwoven fabric 4 times at a water pressure of 100 kgf / cm ² in the 4th stage to produce a split fiber nonwoven fabric with a basis weight of 50 g / m ² . About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

[Comparative Example 7]
(A) Propylene polymer part (A) propylene polymer [density 0.910 g / cm ³ , melting point 157 ° C., Mw / Mn 2.7] with a load of 2160 g and an MFR of 230 ° C. of 35 g / 10 min as a propylene polymer part, As the high-density polyethylene part, high-density polyethylene (density: 0.972 g / cm ³ ) having a load of 2160 g and an MFR of 190 ° C. of 16 g / 10 min was melted at 240 ° C. in each separate extruder molding temperature. (a) Split type composite length in which the weight ratio of the propylene polymer part to the high density polyethylene part is 50/50 using a split type composite fiber spinning die having a total number of segments of 16 in the cross-sectional shape as in a) The fiber is spun by a so-called spunbond method at a yarn speed of 2500 m / min, deposited on a collecting belt, and then a fiber having a hole diameter of 0.11 mm is used to divide the fiber. As 10cm distance from the nozzles to the non-woven fabric using the Le, with in the first stage pressure 60 kgf / cm ^2, 2 stage pressure 100 kgf / cm ² line speed 5 m / min, the 3-stage water pressure 100 kgf / cm ² A total of 8 water jets were applied to the front and back surfaces of the nonwoven fabric 4 times at a water pressure of 100 kgf / cm ² in the 4th stage to produce a split fiber nonwoven fabric with a basis weight of 50 g / m ² . About the obtained nonwoven fabric, the division ratio, the fineness, the bending resistance, and the tensile strength were measured and evaluated. The results are shown in Table 1.

  As is apparent from Table 1, the composite long fiber nonwoven fabric using the polypropylene and polyethylene of Example 1, Example 2 and Example 3 can be easily divided with a splitting ability of 80% or more. The fineness was also thin, and it was extremely excellent in flexibility and texture.

  On the other hand, the composite long fiber nonwoven fabric using the polypropylene and polyethylene of Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, Comparative Example 6, and Comparative Example 7 is difficult to divide. The fineness could not be reduced and the flexibility and texture were poor.

  The split-type composite fiber nonwoven fabric that can be obtained by the method for producing a split fiber nonwoven fabric of the present invention is extremely excellent in flexibility and texture, and various wiping cloths, nonwoven fabrics for clothing such as surgical clothes, medical gowns, and industrial gowns, It can also be used widely for packaging cloth, surface materials for sanitary materials such as disposable diapers and napkins, bedding such as bed sheets and pillow covers, carpets and base fabrics for artificial leather.

  Other applications include VTR and compact disc cleaning cloths, disc polishing, filter cloths, filters, battery separators, general consumer materials such as glass, precious metals, luxury items, window glass, OA equipment, automobile windows, Examples include dirt removal for instruments and mirrors, oil film removal, flooring, and toilet cleaners.

Claims (9)

(A) a load of 2160 g, a MFR at 230 ° C. of 50 to 500 g / 10 min , and (B) a high-pressure low-density polyethylene,
A split-type composite continuous fiber obtained by a spunbond method in which a resin part made of (A) and a resin part made of (B) are in contact with each other. The split composite long fiber obtained by the spunbond method according to claim 1, wherein (A) Mw / Mn (ratio of weight average molecular weight / number average molecular weight) of the propylene-based polymer is less than 5.0. (B) A split-type composite long fiber obtained by the spunbond method according to claim 1, wherein the high-pressure low-density polyethylene has a load of 2160 g and an MFR at 190 ° C of 20 g / 10 min or more. A non-woven fabric comprising split-type composite continuous fibers obtained by the spunbond method according to claim 1 or 2.   A split fiber nonwoven fabric obtained by splitting (A) a propylene-based polymer portion and (B) a high-pressure method low-density polyethylene portion of a split-type composite long fiber by applying stress to the nonwoven fabric according to claim 4.   The split fiber nonwoven fabric according to claim 5, wherein the stress is applied using a high-pressure liquid flow. (A) Propylene polymer having a load of 2160 g and an MFR at 230 ° C. of 50 to 500 g / 10 min , and (B) high-pressure low-density polyethylene were ejected from a spinneret having a composite spinning nozzle and spun. (A) While a composite long fiber in which a propylene-based polymer part and (B) a high-pressure method low-density polyethylene part are in contact with each other is cooled by a cooling fluid, a tension is applied to the long fiber with a fluid to make it fine, A method for producing a nonwoven fabric comprising split-type composite continuous fibers, characterized in that a propylene-based polymer portion is oriented and crystallized and then collected and deposited on a collection belt. A split fiber characterized by splitting (A) the propylene-based polymer part and (B) the high-pressure method low-density polyethylene part of the split-type composite long fiber by applying stress to the nonwoven fabric according to claim 7. Nonwoven fabric manufacturing method.   The method for producing a split fiber nonwoven fabric according to claim 8, wherein the stress is applied using a high-pressure liquid flow.