JP2002069753A - Core-sheath type polyolefin conjugate fiber and nonwoven fabric composed of the same fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a core-sheath type polyolefin conjugate fiber excellent in spinning stability and capable of providing a nonwoven fabric having soft touch feeling and high strength and free from fuzz and a hot-bonding type nonwoven fabric. SOLUTION: This (eccentric) core-sheath type polyolefin conjugate fiber is obtained by using a resin composition composed of 98-85 wt.% polypropylene having a specific fluidity and 2-15 wt.% one more kinds of polyethylenes selected from a specific high-density polyethylene, low-density polyethylene, straight-chain low-density polyethylene and polyethylene polymerized by using metallocene catalyst as a core component and using a specific high-density polyethylene or a polyethylene polymerized by using a specific metallocene catalyst as a sheath component. This nonwoven fabric is composed of the above fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin composite fiber and a nonwoven fabric comprising the same, and more particularly, to a core-sheath type or an eccentric core-sheath type which gives a nonwoven fabric which is excellent in spinnability, excellent in texture and strength, and free of fluff. The present invention relates to a polyolefin composite fiber and a nonwoven fabric made of the fiber.

[0002]

2. Description of the Related Art Non-woven fabrics include disposable diapers, sanitary napkins,
A wide range of fields including hygiene materials such as masks and patches, automotive interior materials such as ceiling materials and sheets, agricultural materials, construction materials, civil engineering materials, battery separators, filters for drinking water, and industrial filters. Used in In these fields, a strong nonwoven fabric is required, in which the strength of the fiber itself and the adhesive strength between the fibers are related. Further, in the field of sanitary materials such as disposable diapers and sanitary napkins, the texture of the nonwoven fabric, that is, a softer and softer texture is required. In order to satisfy these requirements, various materials for fibers constituting the nonwoven fabric and methods for bonding the fibers have been studied and proposed. Polyolefins, polyesters, polyurethanes, and the like are used as fiber raw materials, but inexpensive and hygienic polyolefins are often used for general-purpose products. Among the polyolefins, polypropylene is widely used in disposable nonwoven fabrics such as disposable diapers and sanitary napkins because of its good spinnability, heat resistance and water resistance.

[0003] In a nonwoven fabric manufacturing process, a method of entanglement and fusion of fibers with each other is currently mainly performed by a heating oven method or a pressure bonding method using a hot roll. In the production of nonwoven fabric using polyolefin fiber such as polypropylene fiber, in order to perform the work in the thermocompression bonding process smoothly,
The core-sheath type composite fiber is used. Generally, a low-melting resin is used for the sheath component, and polypropylene having a high melting point is used for the core component, so that the composite fiber has a difference in melting point between the core and the sheath. Thereby, the heating (compression bonding) temperature at the time of fusion can be performed at as low a temperature as possible, and the texture of the nonwoven fabric can be kept soft and the fusion strength between fibers can be improved. It is known that a nonwoven fabric made of a fiber using a polypropylene resin having a high melting point for the core and a polyethylene resin having a low melting point for the sheath is flexible and has a good tactile sensation (JP-A-10-219521, etc.). ). Further, when a fiber composed of a blended structure in which octene-1 containing linear low density polyethylene having a specific MFR and heat of fusion and crystalline polypropylene having a specific MFR are mixed at a specific ratio, a spinning nozzle is used. It is also known that spun bonding can be performed by high-speed take-off without causing stains on the surface, and a spunbonded nonwoven fabric excellent in flexibility and texture can be obtained (Japanese Patent Laid-Open No. 6-322609). However, in these methods, the balance between the flexibility and the strength of the nonwoven fabric is still insufficient. Particularly, in the case of the core-sheath type composite fiber, there is a problem that fluffing occurs on the surface of the nonwoven fabric after thermal fusion due to interface separation between the core and the sheath. Have.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-bondable nonwoven fabric which solves the above-mentioned drawbacks, has excellent spinning stability, has a good tactile sensation, has a soft texture and high strength, and has no fluff. An object of the present invention is to provide a polyolefin composite fiber to be provided and a non-woven fabric comprising the same.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a resin composition in which a polypropylene having a specific fluidity and a specific polyethylene are blended in a specific ratio. By using a core-sheath type or eccentric core-sheath type polyolefin composite fiber with a material as a core component and a specific polyethylene as a sheath component, it has excellent spinning stability, has a good tactile sensation, soft texture and high strength. It has been found that a heat-bondable nonwoven fabric having no fluff can be obtained, and the present invention has been completed.

That is, according to the first aspect of the present invention,
The core-sheath type or eccentric core is composed of a core component (A) and a sheath component (B) shown below, and the sheath component (B) is present at least partially on the fiber surface in the length direction of the fiber. A sheathed polyolefin composite fiber is provided. Core component (A): a resin composition comprising the following components (a) and (b). Component (a) polypropylene having a melt flow rate (230 ° C., 2.16 kg load) of 4 to 200 g / 10 min: 98 to 85% by weight Component (b) having a density of 0.942 to 0.965 g / cm ³ high density polyethylene, low density polyethylene, linear low density polyethylene and the density of the density of 0.9 20~0.941g / cm ³ 0.87 a density of 0.911~0.930g / cm ³ 5~0 At least one type of polyethylene selected from polyethylene polymerized using a metallocene catalyst of 0.910 g / cm ³ and having a melt flow rate (190 ° C., 2.16 kg load) of 6 to 50 g / 10 minutes: % By weight Sheath component (B): 0.942 to 0.965 g / cm in density
³ , a high-density polyethylene having a melt flow rate (190 ° C., 2.16 kg load) of 6 to 50 g / 10 min and / or a density of 0.875 to 0.910 g / cm ³
A polyethylene polymerized using a metallocene catalyst having a melt flow rate (190 ° C., 2.16 kg load) of 6 to 50 g / 10 min.

According to a second aspect of the present invention, the core component (A) and the sheath component (B) are measured at a heating rate of 10 ° C./min by a differential scanning calorimeter (DSC). A polyolefin composite fiber having a difference in melting point of 10 ° C. or more.

According to a third aspect of the present invention, in the core component (A), the temperature rise rate of the component (a) and the component (b) by a differential scanning calorimeter (DSC) at 10 ° C./min. Provided is a polyolefin composite fiber having a difference in melting point of 10 ° C. or more as measured by the method.

Further, according to a fourth aspect of the present invention, there is provided a nonwoven fabric obtained by thermocompression bonding the above-mentioned polyolefin composite fiber.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the core-sheath type polyolefin composite fiber of the present invention and a nonwoven fabric comprising the same will be described in detail.

[I] Core-sheath type polyolefin composite fiber Core Component (A) In the core-sheath type polyolefin composite fiber of the present invention, the core component (A) of the composite fiber is a resin composition comprising the following components (a) and (b).

(1) Component (a) The polypropylene used for the component (a) of the present invention may be a homopolymer of propylene or a copolymer of propylene with ethylene and / or an α-olefin. Is also good. As the α-olefin, specifically, 1-butene,
Examples thereof include 1-hexene, 1-octene, 1-nonene, 1-decene, 3-methyl-1-butene, and 4-methyl-1-pentene. The content of these α-olefins is preferably 10% by weight or less in order to maintain the balance between the strength and the feeling of the conjugate fiber. Preferred polypropylenes used for the component (a) of the present invention include, for example, homopolypropylene and ethylene-propylene random copolymer. These polypropylenes may be used alone or in combination of two or more.

The polypropylene used for the component (a) of the present invention has a melt flow rate (hereinafter abbreviated as MFR) of from 4 to 200 measured at 230 ° C. under a load of 2.16 kg.
g / 10 minutes, preferably 15 to 100 g / 10 minutes. If the MFR is less than 4 g / 10 minutes, the spinning pressure becomes too high, making it difficult to draw at a high magnification, and causing adverse effects such as non-uniform fiber diameter and uneven fiber strength. Conversely, M
When the FR exceeds 200 g / 10 minutes, the melt viscosity is too small, and the yarn breakage due to the occurrence of the fluctuation of the filament group during spinning becomes remarkable.

(2) Component (b) The polyethylene used in the component (b) of the present invention is a kind selected from high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polyethylene polymerized using a metallocene catalyst. The above is polyethylene. (I) High-density polyethylene The high-density polyethylene used for the component (b) of the present invention includes:
A homopolymer of ethylene or a copolymer containing an α-olefin having 3 to 12 carbon atoms as a copolymer component, having a density of 0.942 to 0.965 g / cm ³ , preferably 0.9
Polyethylene having a density of 49 to 0.960 g / cm ³ . High-density polyethylene having a density of less than 0.942 g / cm ³ produces a larger amount of smoke, while having a density of 0.965
High-density polyethylene exceeding g / cm ³ has a hard texture, and all are unsuitable. The MF of the high-density polyethylene measured at 190 ° C. under a load of 2.16 kg.
R is 6 to 50 g / 10 minutes, preferably 10 to 30 g /
10 minutes. When the MFR is less than 6 g / 10 minutes, the viscosity at the time of spinning is high and the spinning drawability is poor.
If it exceeds / 10 minutes, the spinnability will be improved, but white powder will be generated and the amount of smoke emitting components will increase.

(Ii) Low-density polyethylene The low-density polyethylene used for the component (b) of the present invention is:
A homopolymer of ethylene or a copolymer containing vinyl acetate as a copolymer component, having a density of 0.911 to 0.930.
g / cm ³ , preferably 0.918 to 0.928 g / c
m is a polyethylene is ^3. The density is 0.911g
/ Cm ³ less than the low-density polyethylene, amount of smoke so many, while low density polyethylene having a density greater than 0.930 g / cm ^3, itself production problems it has not practical. The low-density polyethylene of 190
The MFR measured at 2.degree.
/ 10 minutes, preferably 10 to 30 g / 10 minutes. M
When the FR is less than 6 g / 10 minutes, the viscosity at the time of spin molding is high, and the spinning drawability is poor. On the other hand, when the FR is more than 50 g / 10 minutes, the spinnability is improved, but white powder is generated and the amount of smoke component increases. Or

(Iii) Linear low-density polyethylene The linear low-density polyethylene used for the component (b) of the present invention may be a homopolymer of ethylene or α having 4 to 8 carbon atoms.
- a copolymer of an olefin and a copolymerizable component, density 0.920~0.941g / cm ^3, a polyethylene preferably 0.925~0.940g / cm ^3. Linear low-density polyethylene having a density of less than 0.920 g / cm ³ produces a large amount of smoke, while a density of 0.
A linear low-density polyethylene exceeding 941 g / cm ³ has its own production problems and is not practical. In addition, the linear low-density polyethylene at 190 ° C., 2.
The MFR measured under a load of 16 kg is 6 to 50 g / 10
Min, preferably 10 to 30 g / 10 min. If the MFR is less than 6 g / 10 minutes, the viscosity during spinning is high and the spinning drawability is poor. On the other hand, if it exceeds 50 g / 10 minutes, the spinnability is good, but white powder is generated and the amount of smoke components increases. Or

(Iv) Polyethylene polymerized using a metallocene catalyst Polyethylene polymerized using a metallocene catalyst used in the component (b) of the present invention is a copolymer containing an α-olefin having 4 to 12 carbon atoms as a copolymerization component. A polymer having a density of 0.
875~0.910g / cm ^3, preferably 0.880
It is a polyethylene of ０．９0.905 g / cm ³ . Polyethylene polymerized using a metallocene catalyst having a density of less than 0.875 g / cm ³ has extremely poor spinnability, while polyethylene polymerized using a metallocene catalyst having a density exceeding 0.910 g / cm ³ is It is not practical because of its own production problems. In addition, the polyethylene polymerized using the above metallocene catalyst, 190 ° C.,
2. The MFR measured under a load of 16 kg is 6 to 50 g / 1.
0 minutes, preferably 15 to 30 g / 10 minutes. MFR
Is less than 6 g / 10 minutes, the spinnability is poor.
If it exceeds 0 g / 10 minutes, the strength of the nonwoven fabric will decrease.

The polyethylene polymerized using the metallocene catalyst used in the component (b) of the present invention has a crystallization peak temperature (Tc) at a temperature-decreasing thermogram of 10 ° C./min measured by a differential scanning calorimeter (DSC). Preferably, two or more are observed. The crystallization peak temperature (Tc)
Is preferably 5 ° C. or more, more preferably 8 ° C. or more, between the high temperature side (Tc2: high temperature crystallization peak temperature) and the low temperature side (Tc1: low temperature crystallization peak temperature). Also, T
c2 is preferably 110 ° C. or less, more preferably 1
00 ° C. or lower, desirably 90 ° C. or lower, and Tc1 is:
Preferably 70 ° C or less, more preferably 60 ° C or less,
It is desirably 50 ° C. or less.

The temperature T expressed by the carbon number (c) and the density (d) of the α-olefin of the polyethylene polymerized using the metallocene catalyst used for the component (b) of the present invention.
1 = −1097 + c × 2.3 + d × 1270, whereas temperature T2 = (T1 + 30) or more, temperature-rise melting separation (TR
The total elution amount by EF) is preferably 5% by weight or more of the total elution.

The temperature rise elution fractionation (TREF: Te
mperture RisingElution F
measurement) is described in “Journal o
fApplied Polymer Science,
Vol. 26, Nos. 4217-4231 (1981) "and" Principles of Polymers, 2P1C09 (1985) ". First, a polymer to be measured is completely dissolved in a solvent. Thereafter, cooling is performed to form a thin polymer layer on the surface of the inert carrier. Such a polymer layer is formed such that an easily crystallizable material is formed on the inner side (closer to the surface of the inert carrier), and a hardly crystallizable material is formed on the outer side. Next, when the temperature is continuously or stepwise increased, in the low temperature stage,
The polymer is eluted from the amorphous portion in the target polymer composition, that is, the polymer having a short branching degree with a high degree of branching. The chain is eluted and the measurement is completed. The concentration of the eluted component at such a temperature is detected, and the composition distribution of the polymer can be seen from a graph drawn by the amount of the eluted and the elution temperature.

(3) Mixing ratio of component (a) and component (b) The polypropylene used as the component (a) and the high-density polyethylene used as the component (b) are used in the core component (A) of the present invention. The mixing ratio of one or more polyethylenes selected from high-density polyethylene, linear low-density polyethylene, and polyethylene polymerized using a metallocene catalyst is as follows: component (a) is 98 to 85% by weight; ~ 1
Component (b) is 3 to 10% by weight based on 5% by weight, preferably 97 to 90% by weight of component (a). Component (a)
When the content exceeds 98% by weight (when component (b) is less than 2% by weight), fluffing of the nonwoven fabric is liable to occur, while when the component (a) is less than 85% by weight (component (b) is less than 85% by weight). Fifteen
If it exceeds 10% by weight), the spinnability is inferior and the strength of the nonwoven fabric is also reduced.

Further, in the core component (A), the difference between the melting points of the component (a) and the component (b) measured by a DSC at a rate of 10 ° C./min is preferably 10 ° C. or more. . If the melting point difference is less than 10 ° C., it is easy to peel off at the core-sheath interface, which is not preferable.

2. Sheath component (B) In the core-sheath type polyolefin conjugate fiber of the present invention, as the sheath component (B) of the conjugate fiber, a high-density polyethylene and / or metallocene catalyst is selected from the component (b) of the core component (A). Polyethylene that has been polymerized using the same is used. It is particularly preferable that the component (b) and the sheath component (B) of the core component (A) are the same resin composition. Further, the core component (A) and the sheath component (B) were measured by DSC.
The difference between the melting points measured at a heating rate of ° C / min is preferably 10 ° C or more. When the melting point difference is less than 10 ° C., the core component (A) is partially dissolved too much, so that the texture of the nonwoven fabric becomes hard, and the nonwoven fabric tends to be paper-like, which is not preferable in performance.

3. Additives The core component (A) or the sheath component (B) used in the present invention may optionally contain other additional components as long as the effects of the present invention are not significantly impaired. Such additional components include resin additives used in ordinary polyolefin resins, for example, phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, neutralizers, light stabilizers, ultraviolet absorbers, Nucleating agents, lubricants, antistatic agents, flame retardants, metal deactivators, fillers, and the like. The amount of these additional components is generally about 0.001 to 2% by weight, preferably about 0.01 to 0.8% by weight.

[II] Nonwoven fabric Method for producing core-sheath type polyolefin composite fiber and nonwoven fabric The nonwoven fabric of the present invention is preferably produced by thermocompression bonding the above-mentioned polyolefin composite fiber. That is,
First, additives and the like are added as necessary to the core component (A) and the sheath component (B), respectively, and melt spinning is performed using a (eccentric) core-sheath composite spinneret. After that, it is stretched by air soccer to obtain a composite filament, and after accumulating the composite filament on a conveyor below the air football,
It is manufactured by a spun bond method in which the sheath component is melted and solidified by an embossing roll or the like set at 110 to 135 ° C and the fibers are bonded to each other. When the embossing roll temperature is lower than 110 ° C., the sheath component is insufficiently melted, so that the fibers are insufficiently melt-solidified, and the tensile strength of the nonwoven fabric is lowered, which is not preferable. On the other hand, when the temperature exceeds 135 ° C., the nonwoven fabric obtained by melting excessively becomes hard and the texture deteriorates, which is not preferable.

[0026]

EXAMPLES The present invention will be specifically described with reference to examples below, but the present invention is not limited to these examples. The measurement method and evaluation method used in the present invention are as follows.

(1) Melt flow rate (MFR): J
It was measured according to the melt flow rate (condition: 230 ° C., load 2.16 kgf) of the IS K6758 polypropylene test method. The polyethylene has a melt flow rate of 190 ° C. under a load of 2.000 in accordance with JIS K6760.
It was measured at 16 kgf.

(2) Melting point: Using a differential scanning calorimeter (DSC) manufactured by Perkin-Elmer Co., Ltd., the temperature was rapidly raised to an initial setting of 230 ° C., maintained for 5 minutes, and then at a cooling rate of 10 ° C./min. After cooling to 40 ° C., the temperature was raised again at a rate of 10 ° C./min, and the melting endothermic peak was measured as the melting point.

(3) Spinnability: spinning is performed from a round spinneret having 24 spinning holes at a resin temperature of 230 ° C. and a discharge rate of 0.8 g / min.
The film was drawn at a take-up speed of m / min and evaluated by measuring the number of yarn breaks for 20 minutes. ◎: Number of times of thread break is 0 ○: Number of times of thread break is one △: Number of times of thread break is two times ×: Number of times of thread break is three or more

(4) Hand of the nonwoven fabric: A sensory test was conducted by a panel of five persons, and the evaluation was made according to the following criteria. ◎: All the members are judged to be software ○: Four members are judged to be software △: Three members are judged to be software ×: Judgments other than the above

(5) Fluff of the nonwoven fabric: After rubbing the surface of the nonwoven fabric with a finger, the surface was visually observed and evaluated according to the following criteria. ◎: No fuzz at all ○: Very little fuzz Δ: Very fuzzy X: Very fuzzy

(6) Nonwoven fabric strength: A test piece having a width of 5 cm was measured at a spacing of 10 cm and an elongation speed of 100% per minute in accordance with JIS L1096, and evaluated according to the following criteria. S: Nonwoven fabric strong 13kg / 5cm width or more M: Nonwoven fabric strong 13kg / 5cm width or less

Example 1 (1) Core Component (A) and Sheath Component (B) The core component (A) had a density of 97% by weight of homopolypropylene powder (hereinafter abbreviated as PP-A) of 26 g / 10 min. 0.965 g / cm ³ and MFR of 20 g / cm ³
10 minutes high density polyethylene powder (HDP)
Abbreviated as EA. ) 3% by weight. Also,
HDPE-A powder was used as the sheath component (B).

[0034] 100 parts by weight of each of the above-mentioned core component (A) and sheath component (B) powder were added with
3,5-tris (4-t-butyl-3-hydroxy-
2,6-dimethylbenzyl) -isocyanurate (Cyanox 1790: manufactured by Cytec Industries) and tris (2,4-di-t-butylphenyl)
Phosphite (Ir168: Ciba Specialty
Chemicals Co., Ltd.) and 0.05 parts by weight of calcium stearate as a neutralizing agent were blended using a supermixer, and then blended using a 50 mmφ extruder at 230 ° C. and 75 r.p.m. p. The mixture was melt-kneaded at a screw rotation speed of m to obtain a pellet-shaped core component (A) and a sheath component (B).

(2) Production of core-sheath conjugate fiber and non-woven fabric Using the core component (A) and the sheath component (B), the number of pores was 24.
Melt spinning was performed using a single core-sheath composite spinneret.
Melt spinning is performed at a spinning temperature of 230 ° C and a discharge rate of 0.8 g / min.
The blending was performed at a hole / core-sheath composite ratio of 1/1, followed by drawing with air soccer to obtain a composite long fiber having a fineness of 2 denier. After the composite type long fibers were accumulated on a conveyor below the air soccer, the fibers were fused with each other by an embossing roll set at 125 ° C. to obtain a nonwoven fabric having a basis weight of 50 g / m ² . Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Examples 2-3 A core-sheath composite fiber and a nonwoven fabric were produced in the same manner as in Example 1, except that the mixing ratio of PP-A and HDPE-A of the core component (A) was changed. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Examples 4 and 5 The core component (A), HDPE-A, was prepared at a density of 0.957 g /
In cm ^3, MFR is (hereinafter referred to as HDPE-B.) high density polyethylene powder is 20 g / 10 min instead of,
A core-sheath composite fiber and a nonwoven fabric were produced in the same manner as in Example 1 except that the mixing ratio of PP-A and HDPE-B was as shown in Table 1. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Examples 6 and 7 The PP-A of the core component (A) was replaced with a homopolypropylene powder (hereinafter abbreviated as PP-B) having an MFR of 50 g / 10 minutes, and the mixing ratio of PP-B and HDPE-A Were produced as shown in Table 1 in the same manner as in Example 1 to produce core-sheath composite fibers and nonwoven fabrics. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Examples 8-9 PP-A of the core component (A) was changed to PP-B, HDPE-A was changed to HDPE-B, and the mixing ratio of PP-B and HDPE-B was as shown in Table 1. Except for this, a core-sheath composite fiber and a nonwoven fabric were produced in the same manner as in Example 1.
Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Example 10 The core component (A) HDPE-A was replaced with HDPE-B and density.
Is 0.898 g / cm ³And the MFR is 16g / 10min
Polyethylene pow polymerized using a metallocene catalyst
(Hereinafter abbreviated as MePE) 50:50 (weight ratio).
A core / sheath was prepared in the same manner as in Example 3 except that the mixture was replaced with a mixture.
Production of composite fibers and nonwoven fabrics was performed. Table 1 shows the core-sheath composite
The spinnability of the fiber and the evaluation results of the obtained nonwoven fabric are shown.

Example 11 A core / sheath composite fiber and a nonwoven fabric were produced in the same manner as in Example 3, except that HDPE-A of the core component (A) was changed to MePE. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Example 12 A core / sheath composite was prepared in the same manner as in Example 2 except that HDPE-A of the sheath component (B) was replaced with a mixture of HDPE-A (95% by weight) and MePE (5% by weight). Fabrication of fibers and nonwovens. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Example 13 A core / sheath composite was prepared in the same manner as in Example 3, except that HDPE-A of the sheath component (B) was replaced with a mixture of HDPE-A (65% by weight) and MePE (35% by weight). Fabrication of fibers and nonwovens. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Example 14 The core component (A), HDPE-A, was prepared at a density of 0.918 g /
core / sheath composite fiber and nonwoven fabric in the same manner as in Example 2 except that low density polyethylene powder having an MFR of 20 g / 10 min in cm ³ (manufactured by Nippon Polychem; LJ800, hereinafter abbreviated as LDPE) was used. Was manufactured. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Example 15 The core component (A) HDPE-A was prepared with a density of 0.937 g /
linear low-density polyethylene powder having an MFR of 35 g / 10 min in cm ³ (manufactured by Nippon Polychem; UJ99)
0, hereinafter abbreviated as LLDPE. ), Except that core-sheath composite fibers and nonwoven fabrics were produced in the same manner as in Example 2. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Comparative Example 1 The core component (A) was composed of PP-A (97% by weight) and HDPE.
Core-sheath composite fibers and nonwoven fabrics were produced in the same manner as in Example 1 except that the mixture of -A (3% by weight) was replaced with PP-A (100% by weight). Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Comparative Example 2 The core component (A) was composed of PP-A (97% by weight) and HDPE.
A core-sheath composite fiber and a nonwoven fabric were produced in the same manner as in Example 1, except that the mixture of -A (3% by weight) was replaced with PP-B (100% by weight). Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Comparative Examples 3 to 5 Core / sheath composite fibers were prepared in the same manner as in Comparative Example 1 except that the sheath component (B) was changed from HDPE-A to a mixture of HDPE-A and MePE at the compounding ratio shown in Table 1. And production of non-woven fabric. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

Comparative Example 6 A core / sheath composite fiber and a nonwoven fabric were produced in the same manner as in Comparative Example 1 except that the sheath component (B) was changed from HDPE-A to MePE. Table 1 shows the spinnability of the core-sheath composite fiber and the evaluation results of the obtained nonwoven fabric.

[0050]

[Table 1]

[0051]

The core-sheath type polyolefin composite fiber of the present invention and the nonwoven fabric comprising the same use a resin composition in which a specific polypropylene and a specific polyethylene are blended in a specific ratio in a core component of the composite fiber, and a specific sheath component is used. Because of the use of polyethylene, the conjugate fiber has excellent spinning stability, and the resulting heat-bondable nonwoven fabric has a good tactile sensation, a soft texture, a high strength, and a non-fuzzy nonwoven fabric. And can be suitably used as a surface material for sanitary materials.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toru Matsumura 3-1 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Japan F-term in Material Development Center, Polychem Co., Ltd. 4L041 AA07 BA21 BA22 BA49 BC04 BD11 CA37 CA41 DD01 4L047 AA14 AA27 AB03 BA09 BB01 BB02 BB09 CB10 CC03 EA05 EA10

Claims (4)

[Claims] 1. A core component (A) and a sheath component (B) shown below.
Wherein the sheath component (B) is arranged in a core-sheath type or an eccentric core-sheath type so that at least a part of the fiber surface is continuously present in the fiber length direction. Core component (A): a resin composition comprising the following components (a) and (b). Component (a) polypropylene having a melt flow rate (230 ° C., 2.16 kg load) of 4 to 200 g / 10 min: 98 to 85% by weight Component (b) having a density of 0.942 to 0.965 g / cm ³ high density polyethylene, low density polyethylene, linear low density polyethylene and the density of the density of 0.9 20~0.941g / cm ³ 0.87 a density of 0.911~0.930g / cm ³ 5~0 At least one type of polyethylene selected from polyethylene polymerized using a metallocene catalyst of 0.910 g / cm ³ and having a melt flow rate (190 ° C., 2.16 kg load) of 6 to 50 g / 10 minutes: % By weight Sheath component (B): 0.942 to 0.965 g / cm in density
³ , a high-density polyethylene having a melt flow rate (190 ° C., 2.16 kg load) of 6 to 50 g / 10 min and / or a density of 0.875 to 0.910 g / cm ³
A polyethylene polymerized using a metallocene catalyst having a melt flow rate (190 ° C., 2.16 kg load) of 6 to 50 g / 10 min. 2. The difference between the melting points of the core component (A) and the sheath component (B) measured at a heating rate of 10 ° C./min by a differential scanning calorimeter (DSC) is 10 ° C. or more. The polyolefin conjugate fiber according to the above. 3. In the core component (A), the difference between the melting point of the component (a) and that of the component (b) measured by a differential scanning calorimeter (DSC) at a heating rate of 10 ° C./min is 10 ° C. or more. The polyolefin composite fiber according to claim 1 or 2. 4. A nonwoven fabric obtained by thermocompression bonding the polyolefin composite fiber according to claim 1.