JP3261028B2 - Self-adhesive composite fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel self-adhesive fiber comprising a naturally degradable polymer.

[0002]

2. Description of the Related Art As one of functional synthetic fibers, there is a self-adhesive fiber which adheres by heating. Thread using it,
After fabricating a knit, woven, nonwoven or other structure, the structure is heated to obtain a strong product with fibers bonded together. However, synthetic fibers made from petroleum must be reviewed from the viewpoint of environmental protection. Normal synthetic fibers are
This is because, when disposed after use, there is a problem that the decomposability is low in the natural environment and the amount of heat generated during incineration is large, damaging the furnace. For this reason, it is desirable to replace synthetic fibers with aliphatic polyester fibers that decompose in the natural environment as much as possible. Aliphatic polyester fibers, polyglycolic acid, polylactic acid, polyhydroxybutyrate, polybutylene succinate, copolymers containing them as a main component, those based on various other aliphatic resins are known,
Those fibers, particularly those having a melting point of 150 ° C. or more and having excellent heat resistance, do not necessarily have the above-mentioned heat adhesiveness and tend to be rather inferior, and need to be improved.

[0003] JP-A-6-207320 and JP-A-6-207324 disclose core-sheath conjugate fibers in which the core is composed of a high-melting-point biodegradable polymer and the sheath is composed of a low-melting-point biodegradable polymer. Short fibers and long fibers have been proposed. However, the examples merely show composite fibers having a sheath of polyethylene succinate having a melting point of 102 ° C. and a core of polybutylene succinate having a melting point of 118 ° C., and their adhesive strength is not so strong. Only 1 melting point difference between both components
This is because since the temperature is as low as 6 ° C., the high melting point component is softened and deteriorated by heating for bonding.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel self-adhesive fiber which is naturally decomposable, has sufficient heat resistance, and can be easily and strongly adhered by heating.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
(1) a low-melting polymer (A) containing an aliphatic polyester having a melting point or softening point of 50 to 140 ° C. as a main component, and (2)
The low-melting-point polymer (A) comprises polycaprolactone,
Ethylene suberate, polyethylene sebacate, polyet
Tylene decamethylate, polybutylene succinate,
Ributylene adipate, polybutylene sebacate, poly
Homopolymer selected from hexamethylene sebacate
Or, it is composed of a copolymer containing
(3) the melting point of the high melting point polymer (B) is at least 30 ° C. higher than the melting point or softening point of the low melting point polymer (A).
(4) the segment forming at least a part of the molecular chain of the high melting point polymer (B) is the same as the segment forming at least a part of the molecular chain of the low melting point polymer (A), and The weight ratio of the common segment is at least 3% in both polymers, and (5) the low melting point polymer (A) has a melting endotherm of 20 J / gram of polymer.
g or more, and the low-melting polymer (A) occupies at least a part of the fiber surface.

Here, the polymer containing an aliphatic polyester as a main component includes (1) an aliphatic hydroxycarboxylic acid such as glycolic acid, lactic acid, and hydroxybutylcarboxylic acid, (2) glycolide, lactide, butyrolactone,
Aliphatic lactones such as caprolactone, (3) ethylene glycol, propylene glycol, butanediol,
Aliphatic diols such as hexanediol, etc. (4)
Components derived from aliphatic polyester polymerization raw materials, such as aliphatic dicarboxylic acids such as succinic acid, adipic acid and sebacic acid, are used as main components, that is, at least 40% by weight (particularly 50%).
The above), aliphatic polyester homopolymer, aliphatic polyester copolymer, and other components of the aliphatic polyester, for example, aromatic polyester, polyether, polycarbonate, polyamide,
Modified products obtained by copolymerization (block copolymerization and / or random copolymerization) of 60% by weight or less (particularly 50% or less) or / and a mixture of components such as polyurea, polyurethane, and polyorganosiloxane are all included.

The purpose of modifying the aliphatic polyester by copolymerization or mixing is to lower the crystallinity, lower the melting point (lower the polymerization temperature or molding temperature), improve the melt fluidity, toughness, flexibility and elastic recovery. Lowering or increasing adhesiveness, heat resistance and glass transition temperature, improving hydrophilicity and water repellency, improving dyeability, improving or suppressing degradability, and the like.

The characteristic of the aliphatic polyester is that it is decomposed in a natural environment (in soil, freshwater, seawater, compost, etc.) in a relatively short period of time (for example, within 5 years, especially within 3 years). This spontaneous degradability is maintained even in a copolymer or a mixture containing aliphatic polyester as a main component, but various decomposition rates can be obtained by changing components and ratios of the copolymer and the mixture. And an appropriate one can be selected depending on the application. In the present invention, a segment is
Refers to a part of the polymer molecular chain. That is, the segment includes both an oligomer-class polymer in which about 2 to 20 structural (repeating) units are linked and a polymer-grade polymer having a degree of polymerization of 20 or more. However, for the purpose of the present invention, the polymerization degree of the segment is preferably 5 or more, particularly preferably 10 or more, and most preferably 20 or more.

[0009]

1 to 6 show specific examples of the cross section of the self-adhesive fiber of the present invention. In the figure, 1 is a low melting point polymer (A), 2 is a high melting point polymer (B), and both are composited (adhered) to form a single fiber. The low-melting polymer (A) is easily melted by heating, fused to each other or another object, and exhibits self-adhesion. The high melting point polymer (B) is hardly affected by heating for bonding, and retains the shape and strength of the fiber. FIG. 1 shows an example in which a high-melting polymer (B) and a low-melting polymer (A) are composited in a core-sheath type. Occupy. FIG. 2 shows an example of a parallel composite of the two, wherein the adhesive component occupies a part of the fiber surface. FIG. 3 is an example of a five-layer parallel composite in which four layers of the low-melting polymer (A) and one layer of the high-melting polymer (B) are combined, FIG. 4 is an example of a keyhole-type composite, and FIG. 6 shows an example of a parallel type having a non-circular (triangular) cross section, and FIG. 6 shows an example of a radial composite having a non-circular cross section.

In the present invention, in order to maintain self-adhesiveness, the low-melting polymer (A), that is, the adhesive component, must occupy at least a part of the surface of the fiber. However, the composite structure, cross-sectional configuration, polymer, and the like can be freely changed as necessary, and the drawings show only some of the examples. For example, using two kinds of polymers (having different shrinkage properties) as the high melting point polymer (B), it is also possible to produce a ternary composite fiber having both spontaneous crimpability and self-adhesiveness.

[0011] The low-melting polymer (A) (hereinafter sometimes referred to as an adhesive layer) is melted by heating and solidified by cooling to bond fibers and fibrous structures. However, in order to further improve the adhesiveness and realize a higher adhesive strength, the present inventors have intensively studied and completed the present invention. That is, the segments constituting at least a part of the low melting point polymer (A) molecular chain and the segments constituting at least a part of the high melting point polymer (B) molecular chain are at least 3% identical, By employing a polymer (A) having a melting endotherm of 20 J / g or more per gram of polymer, not only high crystallinity and extremely excellent adhesive strength can be obtained, but also rapid adhesiveness is exhibited. Thus, a novel self-adhesive conjugate fiber useful in production and handling has been completed.

Here, the same (common) segment means having the same or substantially the same structural unit.
For example, even if the degree of polymerization is different, if the constituent units are the same, they are regarded as the same (same kind) segment. For example, a polylactic acid segment and a segment obtained by randomly copolymerizing polylactic acid with about 5 mol% or less of polylactic acid are considered to be substantially the same (from the viewpoint of adhesiveness).

[0013] The lower the melting point of the adhesive layer polymer, the easier the bonding step is, which is preferable. However, if the melting point is too low, the adhesive strength will be poor. For this reason, the melting point or softening point of the low melting point polymer (A) needs to be in the range of 50 to 140 ° C., preferably 55 to 135 ° C., and more preferably 60 to 140 ° C.
~ 130 ° C is most preferred. Here, the melting point is a peak value of a melting endothermic peak measured by a scanning differential calorimeter (DSC), and the softening point is a temperature at which the melt viscosity becomes 100,000 poise. The bonding temperature depends on the pressure at the time of bonding.
Degree, especially the melting point is often in the range of about ± 30 ° C.

Examples of such a homopolymer of an aliphatic polyester having a low melting point include polycaprolactone (melting point: about 60 ° C.), polyethylene suberate (64 ° C.), polyethylene sebacate (72 ° C.), polyethylene decamethylate (85 ° C), polybutylene succinate (11
6 ° C.), polybutylene adipate (69 ° C.), polybutylene sebacate (65 ° C.), polyhexamethylene sebacate (75 ° C.) and the like. Many of such homopolymers and copolymers containing the same as a main component (for example, 90% or more) are crystalline, and are therefore of a scanning differential calorimeter (D
SC) shows a clear melting endothermic peak.

A polymer having high crystallinity rapidly solidifies when cooled to a temperature lower than the melting point, so that it is easy to manufacture and handle, and is most preferable as an adhesive layer polymer. The higher the crystallinity, the greater the melting endotherm in DSC analysis. The adhesive layer polymer has a melting endotherm of 20 J / g or more per gram of polymer.

A first group of a particularly preferred embodiment of the present invention is that an aliphatic polyester homopolymer having a melting point of 50 to 140 ° C. is used as the adhesive layer polymer (A), and the homopolyester is incorporated into the molecule as a segment. This is a combination of a group III polyester block copolymer as a high melting point polymer (B). For example, when one of the low melting point homopolymers, polycaprolactone, is used as a low melting point polymer (A), and a polylactic acid / polycaprolactone block copolymer incorporating polycaprolactone as a segment is combined as a high melting point polymer (B). Since both have a common segment (polycaprolactone), particularly excellent adhesive strength can be obtained.

A second group of the preferred embodiments of the present invention is to use a homopolymer of an aliphatic polyester having a melting point of 150 ° C. or higher such as polylactic acid, polyglycolic acid, polyhydroxybutyrate or a copolymer containing these as a main component. A polymer obtained by introducing a segment of the high-melting polymer (B) into a molecule of an aliphatic polyester having a melting point of 50 to 140 ° C. while maintaining its crystallinity is used as a low-melting polymer (B). A). For example, if the high melting point polymer (B) is polylactic acid and the adhesive layer polymer (A) is a polycaprolactone / polylactic acid block copolymer, both have a common polylactic acid segment, so that excellent adhesiveness can be obtained. Can be

A third group of the embodiments of the present invention is that the adhesive layer (A) and / or the high-melting polymer (B) are modified by appropriately copolymerizing or mixing the second component and the third component. Is used. Examples of the purpose of the denaturation are as described above. For example, a polymer obtained by random copolymerization of polylactic acid with its optical isomer or other polyester raw material to lower the melting point or softening point to 140 ° C. or lower is a low melting polymer (A).
It can also be. Generally, in block copolymerization, the melting point tends to decrease gradually, and it is possible to use both random copolymerization for adjusting the melting point and block copolymerization for improving adhesion. In addition, the 1st of the said embodiment-
In the specific examples of the third group, only polylactic acid, polycaprolactone, and a copolymer thereof are shown. However, polyglycolic acid, polyhydroxybutyrate, or the like can be used instead of polylactic acid, and polyethylene can be used instead of polycaprolactone. Sebacate, polybutylene adipate and the like can be used.

The block copolymerization can be carried out in the polymerization step of the polyester, but can also be carried out after the polymerization step. For example, if a polymer or oligomer of a low-melting polyester having a hydroxyl group at one or both molecular terminals is added during the polymerization of lactide or glycolide, a block copolymer of polylactic acid or polyglycolic acid having a low-melting polyester segment can be obtained. . In addition, a mixture of a polymer or oligomer of a low-melting polyester having a hydroxyl group at one or both molecular terminals and a high-melting polyester having a hydroxyl group at one or both molecular terminals is also used as a dicarboxylic acid, a dicarboxylic anhydride, or a dicarboxylic acid. By reacting a polyfunctional compound such as chloride or diisocyanate, a block copolymer having both bonded can be obtained. The bond between the blocks (segments) can be other than an ester bond, for example, a urethane bond, a urea bond, an amide bond, a carbonate bond, an ether bond, and other well-known chemical bonds.

Although the molecular weight of the adhesive layer polymer is not particularly limited, those having a low molecular weight tend to have a high melting rate and therefore tend to have a high bonding speed, and those having a high molecular weight tend to have excellent adhesive strength and durability. You can choose arbitrarily according to. For example, the molecular weight is about 20,000 to 400,000, particularly preferably in the range of 30,000 to 300,000, and the range of 50,000 to 200,000 is most widely used.

The fineness of the fiber of the present invention is not particularly limited, but the fineness of a single fiber is about 0.1 to 1000 denier, and that of a multifilament or staple is 0.1 to 50 single yarn.
About 0 denier, monofilament single yarn 10-10
Those having a denier of about 00 are widely used. The fiber form may be monofilament, multifilament, cut staple, spun yarn or any other.

In the composite fiber of the present invention, the composite ratio of the low-melting polymer (A) and the high-melting polymer (B) is not particularly limited, but generally the cross-sectional area ratio of the low-melting polymer (A) (adhesive layer) Is preferably in the range of about 3 to 70%, especially about 5 to 50%, and the range of about 10 to 30% is most widely used.

The high melting point polymer (B) has a fiber shape, strength,
It is necessary to support heat resistance, etc., and to be hardly affected by the heat of the bonding process. For this reason, its melting point needs to be 30 ° C. or more higher than the melting point or softening point of the low melting polymer (A), particularly preferably 35 ° C. or more, most preferably 40 ° C. or more. Further, the melting point of the high melting point polymer needs to be 150 ° C. or more from the practical viewpoint of withstanding boiling water and disinfection.
It is particularly preferred that the temperature is 60 ° C. or higher. Preferred high melting point polymers include poly-L-lactic acid, poly-D-lactic acid, polyglycolic acid, polyhydroxybutyrate, and various copolymers containing these as main components (50% by weight or more). The high melting point polymer (B) desirably has high strength, and therefore has a molecular weight of 50,000 or more, particularly preferably 80,000 or more, and the range of 100,000 to 300,000 is most widely used.

Another requirement of the high melting point polymer (B) is that it has high adhesiveness to the low melting point polymer (A), so that at least one of the molecular chains of the high melting point polymer (B). The segment occupying the part must be the same as the segment occupying at least a part of the molecular chain of the low melting point polymer (A). By having the same (common) segment in both polymers, the adhesion between them is enhanced and the adhesive strength of the bonded product is significantly improved. It is observed that the larger the amount of the common segment, the higher the adhesive strength. The weight ratio of the segments which the high melting point polymer (B) and the low melting point polymer (A) have in common may be the same or different in both, but the polymer having a low common component ratio ( In A or B), a range of 1% or more, particularly about 2 to 60% is preferable, and a range of about 3 to 40%, particularly 5 to 30% is most widely used.

The composite fiber of the present invention is obtained by subjecting a low-melting polymer (A) and a high-melting polymer (B) to a composite spinning, drawing if necessary.
It can be manufactured by heat treatment. Using a solvent, wet, dry, dry and wet can also be combined spinning method,
Melt composite spinning is most efficient and preferred. That is, both polymers are melted using separate melting devices, for example, a screw extruder, and sent to a composite spinneret according to a composite ratio by a metering pump. The conjugate fiber composited in the spinneret and spun from the spinneret is subjected to drawing, heat treatment, crimping, twining, cutting, or the like, as necessary, to obtain a filament or staple.

Low melting polymer (A) and high melting polymer (B)
The composite ratio with the polymer is arbitrary, but the volume ratio of the low-melting polymer (A) is often about 3 to 90%, particularly about 5 to 60%, and most often about 10 to 50%. .

The speed of melt spinning is optional,
Normal speed of about 2000m / min, 2000-500
A high speed of about 0 m / min and an ultra-high speed of 5000 m / min or more are possible. In ordinary speed spinning, the degree of molecular orientation is low, and drawing is often performed to obtain sufficient strength.
In high-speed spinning, semi-oriented fibers, so-called POY, are obtained, and are often used after being slightly stretched in a later step. Ultrahigh-speed spinning often yields fibers that are almost perfectly oriented, and depending on the conditions, can also yield fibers with very high or very low heat shrinkage. Further, continuous spinning and drawing, that is, a so-called spin draw method can also be applied. The heat treatment after spinning or drawing may be performed as needed, but it is desirable to pay attention to the fact that the melting point of the adhesive layer polymer is low. For the purpose of special effects (such as gluing effect), it is also possible to cause adhesion between filaments by heat treatment.

The conjugate fiber of the present invention can be preferably applied to a so-called spun bond method or a melt blow method in which a nonwoven fabric is formed and adhered simultaneously with melt spinning.

The conjugate fiber of the present invention may contain, if necessary, a coloring agent such as a pigment or a dye, a stabilizer such as an inorganic or organic particle or various fillers, a crystal nucleating agent, an antioxidant, or an ultraviolet absorber; Lubricants, release agents, water repellents, plasticizers, antibacterial agents and other secondary additives can be added.

In the following examples,% and parts are by weight unless otherwise specified. The molecular weight of the aliphatic polyester is a weight average value of the dispersion of the high molecular weight component except for the component having a molecular weight of 500 or less in GPC analysis of a 0.1% chloroform solution of the sample. DSC measurement was performed on a 10 mg sample,
The test was carried out in a nitrogen atmosphere at a heating rate of 10 ° C./min. The adhesive strength of the single fiber was determined by taking two sample single fibers having a length of 10 cm, intersecting them one by one in the direction of 120 °, sandwiching them with a 0.1 mm thick Teflon sheet, and
It was sandwiched between metal heaters of 5 cm × 5 cm, heated at a predetermined temperature of 50 g for 3 seconds, taken out, and taken as a single fiber sample having a length of 6 cm centering on the bonding point.
This is the cutting (peeling) strength when subjected to a tensile test in a room at a temperature of 60 ° C. and a humidity of 60% RH under the conditions of a sample length of 4 cm and a tensile speed of 4 cm / min.

[0031]

[Example 1] One end is a hydroxyl group and has an average molecular weight of 1
80,000 (number average molecular weight 70,000) polycaprolactone 10
Parts, 95 parts of L-lactide having an optical purity of 99.5% or more, 100 ppm of tin octylate as a polymerization catalyst, and Irganox 1010, 0.1 as an antioxidant.
Parts were continuously supplied to a twin-screw kneading extruder at 195 ° C.
After reaction for 18 minutes on average, the mixture was extruded from a die, cooled in water, cut and dried to obtain a chip C1. Further, the chip C1 was heated (solid state polymerization) in a nitrogen stream at 140 ° C. for 4 hours to obtain a polymer P1. The polymer P1 is a poly-L-polycaprolactone having a block copolymer of about 5%.
Lactic acid with a molecular weight of 197000 and a melting point of 169 ° C.
Although the average molecular weight of the polycaprolactone segment in the polymer P1 is not clear, it is estimated to be 20,000 or more because the overall molecular weight is considerably high. The molecular weight may be lower than the raw material polycaprolactone,
This is because there is a possibility of hydrolysis or transesterification by a trace amount of water present in the polymerization system. However, it is certain that the polymer P1 is a copolymer obtained by reacting polylactic acid and polycaprolactone, because its transparency and impact strength are remarkably superior to those of a mixture thereof. That is, the mixture is cloudy and opaque, but the polymer P1 is transparent, and the Izod impact strength of the mixture is about 2 kg · cm.
/ Cm, the polymer P1 is 4 kg · cm / cm or more, and the melting point peak of polycaprolactone disappears in the DSC analysis. It is certain that the polymer P1 is not a random copolymer because the melting point is close to that of polylactic acid.

The poly-L-lactic acid homopolymer obtained in substantially the same manner as the polymer P1 but without copolymerizing polycaprolactone is referred to as P2. Polymer P2 has a molecular weight of 203
000, melting point 172 ° C. Almost the same as the polymer P1, except that 95 parts of polycaprolactone, 5 parts of L-lactide, 20 ppm of tin octylate, 10% of Irganox 1010, and 0.1% are mixed. Polymer P3 has a molecular weight of about 7,500
Was a polycaprolactone in which about 5% of poly L-lactic acid was block-copolymerized, and had a molecular weight of 187000 and a melting point of 58 ° C.

The polymer P1 and polycaprolactone having a molecular weight of 180,000 were melted by separate screw extruders,
Using a spinneret at 20 ° C., a core-in-sheath composite spinning at a composite ratio (volume ratio) of 2/1 with a polymer P1 as a core and a polycaprolactone as a sheath, winding at 1200 m / min, and winding at 50 ° C. It was drawn by a factor of 0.6 to obtain a drawn yarn F1 of 75 denier / 15 filaments. Approximately the same as the drawn yarn F1, except that a core obtained using the polymer P2 and a sheath component using the polymer P3 is referred to as a drawn yarn F2.

For comparison, a drawn yarn F3 was obtained in substantially the same manner as the drawn yarn F1, except that the above-mentioned polycaprolactone was used as the sheath component and the polymer P2 was used as the core component. Similarly, for comparison, a monocomponent fiber obtained from only the polymer P2 in substantially the same manner is referred to as a drawn yarn F4.

The drawn yarns F1 to F4 were heated and bonded to each other, and the adhesive strength of the single fiber was measured. The bonding temperature is 80 ° C. for the drawn yarns F1 to F3 and 168 ° C. for F4. Table 1 shows the adhesive strength of each drawn yarn. As can be seen from the table, it is clear that the fiber of the present invention has excellent adhesive strength and excellent self-adhesiveness as compared with the comparative example.

[0036]

[Table 1] [Example 2] Staples S1 to S4 were produced by converging the fibers F1 to F4 of Example 1 in a tow shape, applying a crimp, and cutting the fibers to a length of 51 mm. Using each staple, a web having a basis weight of 50 g / m ² was prepared by a card method, and pressed using a heated emboss roller at the same temperature and pressure as in Example 1 at a pressure of 10 kg / cm ² to bond (emboss).
The obtained nonwoven fabrics N1 to N4 were obtained. Table 2 shows the results of measuring the tensile strength, elongation, tear strength, and elongation of each nonwoven fabric. It is clear that the nonwoven fabric using the fiber of the present invention has excellent strength.

[0037]

[Table 2]

[0038]

According to the present invention, a novel self-adhesive conjugate fiber which is spontaneously degradable, has excellent adhesiveness, expresses quick adhesiveness, and is useful in production and handling is provided. It is preferably used for applications. That is, the fibers of the present invention are monofilaments, multifilaments, staples, spun yarns, various kinds of yarns, etc., alone or mixed with other fibers or resins, and the like, ropes, strings, knits, woven fabrics,
It is suitably applied to nonwoven fabric, paper, sheet, various molded products, and other structures using various fibers. The fiber of the present invention has the feature of extremely strong adhesive strength, and can exhibit sufficient and quick adhesive strength even with a small amount of use (mixing ratio), and is excellent in production and handling. It is suitable for industrial use where high reliability and workability are required. For example, for a printing screen in which fibers of a woven fabric composed of monofilaments are bonded to each other, the fibers of the present invention having excellent heat resistance and adhesive strength are most suitable. Furthermore, even when discarded, it generates less heat during incineration than conventional synthetic fiber products, and is naturally degraded in soil, freshwater, seawater, compost, etc. Very few, very favorable from the viewpoint of environmental protection. When the fibers of the present invention are used in combination with "other fibers", from the viewpoint of environmental protection, as "other fibers", naturally degradable fibers such as natural fibers and fibers mainly composed of aliphatic polyester are used. It is most desirable to use

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a core-sheath composite fiber showing a specific example of the present invention.

FIG. 2 is a cross-sectional view of a parallel type composite fiber showing a specific example of the present invention.

FIG. 3 is a cross-sectional view of a five-layer parallel conjugate fiber showing a specific example of the present invention.

FIG. 4 is a cross-sectional view of a keyhole-type conjugate fiber showing a specific example of the present invention.

FIG. 5 is a cross-sectional view of a non-circular side-by-side composite fiber showing a specific example of the present invention.

FIG. 6 is a cross-sectional view of a non-circular radial array type composite fiber showing a specific example of the present invention.

[Explanation of symbols]

 1 low melting point polymer (A) 2 high melting point polymer (B)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-310236 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) D01F 8/14

Claims (1)

(57) [Claims] (1) a melting point or a softening point of 50 to 140 ° C.
Low melting polymer mainly comprising an aliphatic polyester and (A), the high-melting polymer comprising an aliphatic polyester (B) and are combined with a 0.99 ° C. or more melting points, (2) The low melting point polymer (A) is polycaprolactone
Polyethylene, polyethylene suberate, polyethylene seba
G, polyethylene decamethylate, polybutylene sacrifice
, Polybutylene adipate, polybutylene sebake
Or polyhexamethylene sebacate
Mopolymer or copolymer based on it
Are al structure, (3) melting point of the high melting polymer (B) is at least 30 ° C. above the melting point or softening point of the low melting polymer (A), (4) high-melting polymer (B) The segment constituting at least a part of the molecular chain is the same as the segment constituting at least a part of the molecular chain of the low melting point polymer (A), and the weight ratio of the common segment is at least 3 in both polymers. (5) The low melting point polymer (A) has a melting endotherm of 20 J / g or more per gram of the polymer, and the low melting point polymer (A) occupies at least a part of the fiber surface. A self-adhesive conjugate fiber characterized by the following.