JP5741225B2 - Heat-fusible composite fiber and non-woven fabric using the same - Google Patents

Description

The present invention relates to a heat-fusible conjugate fiber and a nonwoven fabric using the same. More specifically, the present invention provides a heat-fusible latent crimpable composite fiber and a stretchable nonwoven fabric obtained by using the same.

As a technique for obtaining a nonwoven fabric having stretchability, it is common to produce a sheet by laminating an elastomer resin on a conveyor by a melt blow method and bonding the elastomer resin with a hot roll. However, since the bulkiness of the obtained sheet was very low, the air permeability was low and the texture was impaired. In addition, there is a problem that the surface smoothness is poor due to the friction unique to the elastomer resin (see Patent Document 1).

Therefore, there is a method in which a fiber having latent crimping property is made into a web by a card method, and is entangled by a jet water flow and then subjected to heat treatment to cause crimping (shrinkage treatment) and to give structural expansion and contraction. There is a problem that the strength of the nonwoven fabric is low due to the entangled structure (see Patent Document 2).

As another method, in order to provide both adhesiveness and latent crimpability, a thermoplastic resin having a melting point of 80 to 170 ° C. is used for the sheath portion (fiber outer peripheral portion), and the core portion has a heat shrinkage characteristic having a high melting point of 20 ° C. or more. By making through-air processing a heat-adhesive latent crimped composite fiber using two different thermoplastic resins using the card method and making through-air processing, the adhesiveness and latent crimp due to low-temperature resin are revealed. Although there is a method of giving both nonwoven fabric strength and stretchability by expressing crimps, the sheath part, which is an adhesive component, covers the core part that expresses crimps, so that sufficient crimps do not appear and stretch There exists a problem which impairs performance (refer patent document 3).

JP 2009-256856 A Japanese Patent Application No. 8-268951 Japanese Patent Application No. 6-280147

The subject of this invention is providing the nonwoven fabric obtained by using the fiber from which bulkiness, high nonwoven fabric strength, and the outstanding elasticity are obtained especially when it uses for a nonwoven fabric.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that fibers in which three types of resin components are arranged at specific positions in the fiber cross section perpendicular to the fiber long axis direction, Based on this finding, the present invention has been completed.

The present invention has the following configuration.
(1) A composite fiber obtained by using three types of resin components, a first component, a second component, and a third component, wherein the first component is a resin component having thermal adhesiveness by melting or softening; Its melting point or softening point is lower than the melting point or softening point of the other two components, the second component is a non-heat-shrinkable resin component or a heat-shrinkable resin component that is lower than the third component, and the third component Is a heat-shrinkable resin component, and each component is present independently in a fiber cross section perpendicular to the fiber long axis (hereinafter, also simply referred to as fiber cross section), and the first component centering on the second component. The component and the third component are arranged in parallel, at least the first component continuously occupies a part of the fiber surface in the fiber length direction, and at least a part of the third component is a part of the fiber surface A heat-fusible conjugate fiber that continuously occupies the fiber length direction.
(2) The first component is a resin component containing at least one selected from low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), and thermoplastic elastomer, and the second component is crystalline. The heat-fusible conjugate fiber according to item (1), wherein the heat-fusible conjugate fiber is a resin component containing a conductive polypropylene, and the third component is a resin component containing a propylene-based copolymer.
(3) The heat-fusible conjugate fiber according to (1) or (2), wherein the first component continuously occupies 30 to 80% of the fiber surface in the fiber length direction.
(4) The thermal fusion according to any one of (1) to (3), wherein the melting point of the first component is 70 ° C. or higher and 125 ° C. or lower, and the melting point of the third component is 120 ° C. or higher and 147 ° C. or lower. Composite fiber.
(5) The first component contains a metallocene L-LDPE, and the propylene copolymer contained in the third component has an ethylene content of 4 to 10% by weight and a propylene content of 90 to 96% by weight. The heat-fusible conjugate fiber according to any one of (2) to (4), which is a propylene binary copolymer.
(6) An ethylene-propylene copolymer in which the propylene copolymer contained in the third component has an ethylene content of 1 to 7% by weight, a propylene content of 90 to 98% by weight, and a 1-butene content of 1 to 5% by weight. The heat-fusible conjugate fiber according to any one of (2) to (4), which is butene-1 terpolymer.
(7) A nonwoven fabric obtained using the heat-fusible conjugate fiber according to any one of (1) to (6).

The heat-fusible conjugate fiber of the present invention can give high shrinkage and adhesiveness, and further, after the nonwoven fabric processing, latent crimps are manifested and expressed, resulting in high bulkiness, high nonwoven fabric strength, and excellent A non-woven fabric having high elasticity.

The figure which shows the example of the preferable fiber cross section of the heat-fusible conjugate fiber of this invention (the aspect of Example 1). The figure which shows the example of the preferable fiber cross section of the heat-fusible conjugate fiber of this invention (the aspect of Example 2). The figure which shows the example of the preferable fiber cross section of the heat-fusible composite fiber of this invention (aspect of Example 3). The figure which shows the example of the preferable fiber cross section of the heat-fusible composite fiber of this invention. The figure which shows the example of the preferable fiber cross section of the heat-fusible composite fiber of this invention. The figure which shows the example of the fiber cross section of the comparative example with respect to this invention (the aspect of the comparative example 1). The figure which shows the example of the fiber cross section of the comparative example with respect to this invention (the aspect of the comparative example 2).

The heat-fusible conjugate fiber of the present invention has a low-melting-point (or low softening point) resin (first component) and a heat-shrinking behavior centered on a non-heat-shrinkable resin or a resin having a low heat-shrinkability (second component). It is a composite fiber having fiber cross-sections arranged in parallel so as to be sandwiched between high resins (third component). The principle of the present invention is that the third component having the largest heat shrinkage shrinks when heat-treated to express crimps in the composite fiber, becomes inside the crimps, and has a melting point (from the second and third components) The first component having a low softening point functions as a component involved in thermal bonding, and the other two components melt (or soften outside the crimp without damaging the shape of the crimp even if crimping occurs. ), The adhesive point (the contact points on the outer side of the crimp of the composite fiber are melted and bonded to each other) is formed on the outside of the crimp while maintaining the shape of the crimp even when solidified. Is.

The first component of the heat-fusible conjugate fiber of the present invention is not particularly limited as long as it has a lower melting point or softening point than the other two components and forms a bonding point by melting or softening. Regarding the difference between the melting point (softening point) of the other two components and the lower melting point (or softening point), the first component without melting (softening) other components in the availability of the resin or heat treatment In view of the temperature range when melting (softening), it is preferable to select a material having a temperature lower by 5 to 40 ° C., and more preferably a material having a temperature lower by 10 to 35 ° C. Specific examples of such a first component include a resin component containing at least one selected from LDPE, L-LDPE, and a thermoplastic elastomer.

The second component is not particularly limited as long as it is a resin component that is non-heat-absorbing or has lower heat shrinkage than the third component, and specific examples include a resin component containing crystalline polypropylene.

Although it will not specifically limit if a 3rd component is a heat-shrinkable resin component, Specifically, the resin component containing a propylene-type copolymer can be mentioned.

In the present invention, the first component contributes to adhesion as a resin component having thermal adhesion. The LDPE or L-LDPE used as the first component preferably has a melting point in the range of 70 ° C. or higher and 125 ° C. or lower, and more preferably 95 ° C. or higher and 120 ° C. or lower. If the melting point of the LDPE or L-LDPE contained in the first component is 125 ° C. or less, it is involved in thermal bonding by melting the third component including the propylene copolymer at the temperature at which the first component is thermally melted. Since it can suppress, the formation of the adhesion point in the nonwoven fabric of the third component can be prevented, and the stretchability of the nonwoven fabric can be maintained. In this case, the strength of the nonwoven fabric is sufficiently maintained by the adhesion of the first component. If the melting point of the first component is 70 ° C. or more, carding friction of the metallic wire is suppressed in the carding process for producing the web, and the generation of nep (fiber fusion) does not occur, and the texture is kept good. . Furthermore, L-LDPE is preferably L-LDPE produced using a metallocene catalyst in terms of low-temperature processability, elongation, and surface smoothness.

A thermoplastic elastomer may be used as the first component. When a thermoplastic elastomer is used, it is thermally bonded by being softened by heat. The thermoplastic elastomer preferably has a softening point of 70 to 110 ° C., more preferably 80 to 100 ° C. in terms of processability. Examples of such thermoplastic elastomers include hydrogenated styrene elastomer (SEBS) and thermoplastic polyurethane (TPU). In view of compatibility, olefin elastomers are also preferable examples. Examples of the olefin elastomer include an ethylene-octene-1 copolymer (Engage 8402 manufactured by Dow Chemical Company).

When a thermoplastic elastomer is used as the first component, the contact points between the fibers are thermally bonded via the elastomer component, so that the bonding point itself is elastic and deforms due to tension applied to the nonwoven fabric. As a result, the nonwoven fabric is given flexibility and stretchability, and the adhesive strength of the adhesive point is reinforced by the tackiness of the elastomer component. As a result, the adhesive strength of the adhesive point is also high.

As the first component, one or a mixture of two or more thermoplastic elastomers can be used, and these can also be used as a mixture with LDPE or L-LDPE. The first component may further contain other resins, additives such as lubricants and pigments, or inorganic substances such as calcium carbonate and titanium oxide, as long as the thermal adhesion effect by melting or softening is not inhibited.

The propylene-based copolymer exemplified as the third component is an olefin copolymer mainly composed of propylene. Such a propylene-based copolymer can be obtained by copolymerizing propylene and ethylene, or propylene, ethylene, and α-olefin. Examples of the α-olefin used for the propylene-based copolymer include butene-1, pentene-1, hexene-1, heptene-1, octene-1, 4-methyl-pentene-1, and the like. -Two or more of olefins may be used in combination.

Specific examples of such a propylene copolymer include ethylene-propylene binary copolymer, propylene-butene-1 binary copolymer, ethylene-propylene-butene-1 terpolymer, propylene-hexene. -1 binary copolymer, propylene-octene-1 binary copolymer and the like, and mixtures thereof. These copolymers may be random copolymers or block copolymers.

More preferable specific examples of such a propylene-based copolymer include an ethylene-propylene binary copolymer and an ethylene-propylene-butene-1 terpolymer in terms of low-temperature heat shrinkability. Furthermore, in terms of low temperature heat shrinkability and cost, ethylene-propylene binary copolymer comprising ethylene content 4 to 10% by weight and propylene content 90 to 96% by weight, ethylene content 1 to 7% by weight, propylene Mention may be made of ethylene-propylene-butene-1 terpolymers having a content of 90 to 98% by weight and a 1-butene content of 1 to 5% by weight.

The melting point of the propylene-based copolymer of the third component is preferably 120 ° C. or higher and 147 ° C. or lower, more preferably 125 ° C. or higher and 140 ° C. or lower, provided that the melting point is higher than that of the first component. If the melting point is 120 ° C. or higher, a sufficient difference in melting point from the first component described above can be taken, and melting of the third component can be suppressed simultaneously with melting or softening of the first component. If the melting of the third component can be suppressed, the adhesion point will be formed outside the crimp (first component side) developed by the heat treatment, so the nonwoven fabric becomes soft and the thermal contraction of the third component itself also occurs. Since it can be efficiently expressed without being inhibited by adhesion, a nonwoven fabric rich in stretchability can be produced. Moreover, if melting | fusing point is 147 degrees C or less, since melting | fusing point difference with the crystalline polypropylene used for the 2nd component mentioned later can be taken large, a crimp can be expressed efficiently and it is preferable.

The melting point of the third component is preferably higher than that of the first component from the viewpoint of nonwoven fabric processability, and the difference between the melting points of the third component and the first component (the melting point of the third component minus the first component melting point) is 10 to 70. More preferably, it is in the range of 20 ° C., more preferably in the range of 20-40 ° C.

The melt mass flow rate of the third component is preferably 0.1 to 80 g / 10 min, more preferably 3 to 40 g / 10 min under the condition 14 of JIS-K7210 from the viewpoint of spinnability and workability.
The third component may contain additives such as other resins, lubricants and pigments, or inorganic substances such as calcium carbonate and titanium oxide, as long as these effects are not impaired.

The crystalline polypropylene used for the second component is a propylene homopolymer or a copolymer of propylene and a small amount, usually 2% by weight or less of ethylene or α-olefin. As such a crystalline polypropylene, a crystalline polypropylene obtained from a general-purpose Ziegler-Natta catalyst or a metallocene catalyst can be exemplified. The melting point of the second component is preferably higher than the melting point of the third component from the viewpoint of shrinkage workability, and the melting point difference is preferably in the range of 15 to 45 ° C., more preferably 20 to 30. It is in the range of ° C.
The melt mass flow rate of the second component is preferably 0.1 to 80 g / 10 min, more preferably 3 to 40 g / 10 min under the condition 14 of JIS-K7210 from the viewpoint of spinnability and processability.

In the fiber cross section (cross section perpendicular to the fiber long axis) of the heat-fusible conjugate fiber of the present invention, each component exists independently in the fiber cross section, and the first component and the second component are the center. The third component is arranged in parallel, at least the first component continuously occupies a part of the fiber surface in the fiber length direction, and at least a part of the third component is a part of the fiber surface. Occupies continuously in the length direction. Specific examples of such an embodiment can include fiber cross sections as shown in FIGS. As shown in each of these figures, in the fiber cross section, each component exists independently. In each figure, the first component on the left side and the third component on the right side are arranged with the second component as the center. Yes.

Self-adhesiveness between fibers by having the first component serving as an adhesive component continuously on the surface in the fiber length direction, in particular, occupying 30 to 80% of the fiber surface in the fiber length direction. And the fiber which shows moderate adhesiveness with other raw materials, and has a high latent crimp property by paralleling a 2nd component and a 3rd component is obtained. In particular, it is more preferable in terms of adhesiveness that the first component continuously occupies 30 to 80% of the fiber surface in the fiber length direction.

In the fiber cross section perpendicular to the fiber long axis, each boundary line between the three components arranged in parallel may be a straight line or a curved line independently. In particular, as shown in FIGS. 1 to 3, at least the boundary line between the second component and the third component draws a concave arc toward the third component side (right side in FIGS. 1 to 3) (left side in FIGS. 1 to 3). In the fiber cross section perpendicular to the fiber long axis, the boundary lines of the three components are on the fiber surface side where the first component is not exposed (FIG. 1 to FIG. 1). It is also a preferred form of the fiber of the present invention that a parallel structure is formed which is arranged to draw a concave arc (similarly protruding to the left in FIGS. 1 to 3). One. By taking such a parallel structure, there are many opportunities for the fibers to contact each other via the first component having thermal adhesiveness, and the thermal bonding can be efficiently achieved. Is preferable. The present invention also includes the fiber cross-section shown in FIGS.

As the cross-sectional area ratio of the first component, the second component, and the third component, the area ratio of the second component and the third component is in the range of 40:60 to 60:40, and the total of the second component and the third component More preferably, the ratio of the area of the first component to the area is in the range of 1/3 to 1. If the area ratio of the first component that is the adhesive component to the total area of the second component and the third component is 1/3 or more, the adhesive force by the first component is sufficiently maintained, and the area ratio is 1 or less. If it is, since the quantity of the 1st component is maintained in the range which can eliminate completely the possibility of preventing the thermal contraction of the 3rd component, crimp expression is favorable.

In order to obtain such a fiber cross section perpendicular to the fiber major axis, it can be obtained by using a three-component parallel type composite spinneret shown in Japanese Patent Application No. 2-172718. Using the same mold as described in this document, for example, by controlling the fluidity of the resin (melting temperature, MFR), the cross-sectional shape in which the boundary line between the components forms a concave arc on the third component side Can be efficiently produced. For example, in the case of a resin having the same fluidity, the obtained cross-section becomes a half-moon shape, but as the fluidity of one resin is increased, it changes to a cross-section that covers a resin having low fluidity. By utilizing this fact, the cross-sectional shape between the three components can be changed.

The fineness of the heat-fusible conjugate fiber of the present invention is not particularly limited, but is preferably in the range of 1.0 dtex to 20 dtex, more preferably 1.5 dtex to 10 dtex, and still more preferably 2.2 dtex to 6.6 dtex. . If the fineness is 1.0 dtex or more, it is possible to completely prevent the occurrence of neps in the carding process, and the texture of the nonwoven fabric is good. If it is 20 dtex or less, crimp can be fully expressed.

The heat-fusible conjugate fiber of the present invention is a web having a basis weight of about 100 g / m ² , and when this is left in a 125 ° C. oven for 5 minutes, it easily exhibits a shrinkage ratio of 50% or more. Furthermore, preferably, a shrinkage rate of 60% or more can be expressed.
When the shrinkage rate is 50% or more, the nonwoven fabric can be provided with sufficient stretchability and becomes a soft nonwoven fabric.

For example, another fiber such as another latent crimped conjugate fiber may be blended with the heat-fusible conjugate fiber of the present invention. Another latent crimped composite fiber includes a fiber having a parallel or eccentric cross section composed of only the second component and the third component of the present invention.

A method for producing a nonwoven fabric using the heat-fusible conjugate fiber of the present invention will be described below.
The fiber of the present invention can be formed into a non-woven fabric by heat-sealing the fibers and the latent crimp of the fiber can be developed in one step. An expression step can also be performed. In particular, if the latter method is used, it becomes possible to use a shrink dryer or the like that can apply heat without forming a tension after processing the nonwoven fabric, and it is possible to give higher shrinkage more uniformly.

As a production example in the former case, the heat-fusible conjugate fiber of the present invention is processed by a card method to form a web, and the hot-air circulation type at a processing temperature that is higher than the melting point of the first component and the fiber shrinks. A method of performing adhesion and shrinkage simultaneously through a heat treatment machine (through air machine) can be mentioned. In the latter case, the heat fusible conjugate fiber of the present invention is made into a web using the card method, and a hot air circulation type heat treatment machine (with a processing temperature not lower than the melting point of the first component and not higher than the shrinkage start temperature of the fiber) ( A method of heat-treating with a shrink dryer at a processing temperature not lower than the shrinkage start temperature and not higher than the third component melting point can be mentioned.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not a thing limited to these Examples.

<Fiber>
The first component is an elastomer resin (product name: Engage 8402, manufactured by Dow Chemical Co.) with a melting point of 98 ° C. and MI 30 g / 10 min. The second component is a homopolypropylene resin (manufactured by Nippon Polypro, SA2E) with a melting point of 160 ° C. and MFR 16 g / 10 min. As a component, a propylene copolymer having a melting point of 130 ° C. and an ethylene content of 4% by weight, a butene-1 content of 2.7% by weight and MFR of 16 g / 10 min (manufactured by Nippon Polypro Co., Ltd., SG02) is used. Fibers were obtained by changing the cross-sectional area ratio by extruding at a desired processing temperature using a 230-hole die discharged in a form sandwiched between the component and the third component.
This fiber was stretched 2.5 times with a stretching roller at 90 ° C. to obtain a raw cotton having 2.2 dtex and a cut length of 51 mm.

<Shrinkage measurement method>
The composite fiber is processed into a non-woven fabric by the method shown in each of the following examples, and the length of each center in the MD direction (the flow direction of the machine for manufacturing the non-woven fabric) and its three ends are measured on the sample before the heat treatment. (A) Value. Next, after the heat treatment, the same measurement was made, and the average was taken as the value (B), and the shrinkage was obtained by the following formula. The heat treatment was performed in an oven at temperatures of 100 ° C. and 125 ° C., and the results were measured.
Shrinkage rate (%) = ((A) − (B)) / (A) × 100

Example 1
A fiber in which the area ratio of the second component and the third component in the fiber cross section is 50:50 and the ratio of the area of the first component to the total area of the second component and the third component is ½ is used. The fiber had a cross section as shown in FIG. 1, and the first component continuously occupied 33% of the fiber surface in the fiber length direction in the cross section perpendicular to the fiber major axis. The shrinkage rate was 3% in the measurement of the shrinkage rate at 100 ° C. in the oven, and the shrinkage rate was 70% in the measurement of the shrinkage rate in the oven 125 ° C.
A web having a basis weight of 30 g / m ² was produced from this fiber using a miniature card machine, and a nonwoven fabric was formed using an air-through machine having a processing temperature of 100 ° C. Next, air-through processing was performed at a processing temperature of 125 ° C., and thermal shrinkage treatment was performed.
The obtained nonwoven fabric was flexible and exhibited high strength and stretchability.

Example 2
A fiber in which the area ratio of the second component and the third component in the fiber cross section is 40:60 and the ratio of the area of the first component to the total area of the second component and the third component is 1/3 was used. The fiber had a cross section as shown in FIG. 2, and the first component continuously occupied 20% of the fiber surface in the fiber length direction in the cross section in the direction perpendicular to the fiber major axis. The shrinkage rate was 7% in the measurement of the shrinkage rate at 100 ° C. in the oven, and 78% in the measurement of the shrinkage rate in the oven 125 ° C.
A web having a basis weight of 30 g / m ² was produced from this fiber using a miniature card machine, and a nonwoven fabric was formed using an air-through machine having a processing temperature of 100 ° C. Next, air-through processing was performed at a processing temperature of 125 ° C., and thermal shrinkage treatment was performed.
The obtained non-woven fabric was soft and highly stretchable.

Example 3
A fiber in which the area ratio of the second component and the third component in the fiber cross section is 60:40, and the ratio of the area of the first component to the total area of the second component and the third component is 1/2. The fiber had a cross section as shown in FIG. 3, and the first component continuously occupied 48% of the fiber surface in the fiber length direction in the cross section perpendicular to the fiber major axis. The shrinkage ratio measured at an oven of 100 ° C. was 1%, and the shrinkage ratio measured at an oven of 125 ° C. was 68%.
A web having a basis weight of 30 g / m ² was produced from this fiber using a miniature card machine, and a nonwoven fabric was formed using an air-through machine having a processing temperature of 100 ° C. Next, air-through processing was performed at a processing temperature of 125 ° C., and thermal shrinkage treatment was performed.
The obtained nonwoven fabric was soft and stretchable.

Comparative Example 1
The second component and the third component are arranged side-by-side (in parallel), and the area ratio in the fiber cross section is 50:50, the ratio of the area of the first component to the total area of the second component and the third component Was 1/3 and the fiber shown in FIG. 6 surrounding the outer periphery was used. The shrinkage rate was 0% in the measurement of the shrinkage rate at 100 ° C. in the oven, and the shrinkage rate was 40% in the measurement of the shrinkage rate in the oven 125 ° C.
A web having a basis weight of 30 g / m ² was produced from this fiber using a miniature card machine, and a nonwoven fabric was formed using an air-through machine having a processing temperature of 100 ° C., and then air-through processing was performed at a processing temperature of 125 ° C. However, the stretchability of the nonwoven fabric obtained with small shrinkage was low.

Comparative Example 2
The second component and the third component are arranged side-by-side, the area ratio in the fiber cross section is 50:50, and the ratio of the area of the first component to the total area of the second component and the third component is 1 / No. 3, fibers having an eccentric structure surrounding the outer periphery (FIG. 7) were used. The shrinkage rate was 30% in the measurement of the shrinkage rate at 100 ° C. in the oven, and the shrinkage rate was 50% in the measurement of the shrinkage rate in the oven 125 ° C.
When a web having a basis weight of 30 g / m ² was produced from this fiber with a miniature card machine and made into a nonwoven fabric with an air-through machine having a processing temperature of 100 ° C., formation defects due to shrinkage were noticeable in the nonwoven fabric. Next, an air-through process was performed at a processing temperature of 125 ° C., and a heat shrink process was performed. Therefore, the obtained nonwoven fabric had low stretchability.

  The results of the above examples and comparative examples are summarized in Table 1.

The effect of the present invention is that high shrinkability and adhesiveness can be given, and further, after processing of the nonwoven fabric, a non-woven fabric having high bulkiness, high nonwoven fabric strength, and excellent stretchability can be obtained due to the development of latent crimps. From, for example, it can be used for a haptic base fabric, a diaper stretch material, a shrink nonwoven fabric, and the like.

Claims (4)

A composite fiber obtained by using three types of resin components, a first component, a second component, and a third component, wherein the first component is a resin component having thermal adhesiveness by melting or softening, and its melting point or The softening point is lower than the melting point or softening point of the other two components, the second component is a resin component that is non-heat-shrinkable or has a lower heat-shrinkability than the third component, and the third component is heat-shrinkable The first component is a resin component containing at least one selected from low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), and thermoplastic elastomer, The two components are resin components containing crystalline polypropylene, the third component is a resin component containing a propylene-based copolymer,
(1) The first component contains L-LDPE polymerized with a metallocene catalyst, and the propylene copolymer contained in the third component has an ethylene content of 4 to 10% by weight and a propylene content of 90 to 96%. % Ethylene-propylene binary copolymer, or
(2) An ethylene-propylene-butene having a propylene-based copolymer contained in the third component having an ethylene content of 1 to 7 wt%, a propylene content of 90 to 98 wt%, and a 1-butene content of 1 to 5 wt% -1 terpolymerization,
The respective components are present independently in the fiber cross section perpendicular to the fiber long axis, the first component and the third component are arranged in parallel around the second component, and at least the first component is a fiber. A heat-fusible conjugate fiber that occupies a part of the surface continuously in the fiber length direction and at least a part of the third component occupies a part of the fiber surface continuously in the fiber length direction. The heat-fusible conjugate fiber according to claim 1, wherein the first component continuously occupies 30 to 80% of the fiber surface in the fiber length direction. The first component melting point of 70 ° C. or higher 125 ° C. or less, heat-fusible composite fiber according to any one of claims 1-2 melting point of the third component is 120 ° C. or higher 147 ° C. or less. A nonwoven fabric obtained using the heat-fusible conjugate fiber according to any one of claims 1 to 3 .

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