JP2002227036A - Aliphatic polyester yarn for carpet and carpet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aliphatic polyester yarn providing a carpet which has excellent bulkiness and wear resistance and can be lightened by excellent covering properties and a carpet, especially a carpet having excellent performances for automobiles by using the aliphatic polyester yarn as a face yarn. SOLUTION: This aliphatic polyester yarn for a carpet is characterized in that the fiber is an assembly of hollow sectional single filaments obtained by subjecting an aliphatic polyester having >=145 deg.C melting point to melt spinning and is constituted of aliphatic polyester multifilament having 500-5,000 dtex total fineness and the hollow sectional single filaments have >=3 μm thickness composed of a gap between an outer wheel part and the contour part of the hollow part. This carpet is obtained by using the aliphatic polyester yarn as a face yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aliphatic polyester yarn for carpet and a carpet.

More specifically, it is excellent in bulkiness and durability,
The present invention relates to an aliphatic polyester yarn suitable for a face yarn of a carpet and a carpet using the aliphatic polyester yarn as a face yarn and exhibiting excellent performance particularly for an automobile.

[0003]

2. Description of the Related Art Aliphatic polyester fibers are used for agricultural materials, civil engineering materials and the like by taking advantage of their excellent biodegradability.
No. 4378, for example.

[0004] However, the aliphatic polyester multifilaments described above have a higher specific gravity than other fiber materials such as polyamide filaments and polyolefin filaments, and it is difficult to obtain sufficient bulkiness. It is often insufficient for applications such as carpets for automobiles, which are required and bulky is required.

[0005] Further, if it is simply attempted to hollow the single-filament cross section of the aliphatic polyester filament in order to improve the above-mentioned drawback of the specific gravity, the single-filament breakage is likely to occur in the filament-making process. ,
There is also a major problem that the hollow portion is broken during use as a carpet and fibrillation is likely to occur.

Further, in order to give a bulky crimp suitable for a face yarn of a carpet to an aliphatic polyester multifilament, it is necessary to stretch the aliphatic polyester multifilament at a high stretching ratio immediately before giving a fluid crimp. At this time, there has been a problem that the breaking of the single yarn frequently occurs due to the breakage of the hollow portion, and the yarn breaks in the heated fluid crimping device.

The above-mentioned problem is a phenomenon that occurs particularly remarkably in the case of an aliphatic polyester filament. In order to make up for the above-mentioned drawback of the specific gravity, the drawing process is stabilized when the cross section of a single yarn is hollowed out, and excellent. The fact is that aliphatic polyester yarns for carpets that simultaneously satisfy both wear durability and bulkiness have not been realized.

[0008] Similarly, conventional carpets using aliphatic polyester yarns, especially carpets for automobiles, still have further problems in terms of bulkiness, weight reduction, wear resistance and the like.

[0009]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying to solve the above-mentioned problems in the prior art.

That is, an object of the present invention is to provide an aliphatic polyester yarn which is excellent in bulkiness and durability and which can provide a carpet which can be reduced in weight by good covering properties, and using this aliphatic polyester yarn. Another object of the present invention is to provide a carpet having excellent performance particularly for a carpet or the like.

Still another object of the present invention is to provide a carpet capable of reducing the burden on the natural environment associated with disposal after use required for automobile products.

[0012]

In order to achieve the above-mentioned object, the aliphatic polyester yarn for carpet of the present invention comprises:
An aggregate of hollow cross-section single yarn obtained by melt-spinning an aliphatic polyester having a melting point of 145 ° C. or more, and has a total fineness of 500 to
The hollow cross-section single yarn is composed of an aliphatic polyester multifilament of 5000 decitex, and a thickness defined by a distance between an outer contour and a hollow portion contour is 3 μm or more.

[0013] In the aliphatic polyester yarn for carpet, the polyester hollow cross-section single yarn as a raw material has an outer shape formed by three peaks and three valleys protruding to the outside, and the fiber has a fiber shape. It is desirable to have one to three hollow portions in the axial direction.

Further, in the aliphatic polyester yarn for carpet, the aliphatic polyester multifilament preferably contains 0.1 to 3.0% by weight of a coloring agent, and more preferably, the coloring agent is a carbon black-based coloring agent. It is characterized by being an agent.

The carpet of the present invention has a melting point of 145.
A polyester having a hollow cross-section obtained by melt-spinning an aliphatic polyester at a temperature of at least 0 ° C., comprising an aliphatic polyester multifilament having a total fineness of 500 to 5000 decitex, wherein the hollow cross-section single yarn has an outer contour. Characterized in that an aliphatic polyester yarn for carpet is used as a face yarn, characterized in that the thickness comprising the distance between the hollow portion and the contour of the hollow portion is 3 μ or more, and that it is used particularly as a carpet for automobiles. .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The aliphatic polyester used in the present invention must have a melting point of 145 ° C. or higher. When the melting point is lower than 145 ° C, the quality of the product is remarkably low, such as poor stretchability due to generation of fusion between the single yarns, and melting defects during dyeing, heat setting, and friction heating. Therefore, it is difficult to use for carpet applications. The melting point of the aliphatic polyester used in the present invention is preferably 160 ° C. or higher. Here, the melting point means a peak temperature of a melting peak obtained by DSC measurement.

In the aliphatic polyester used in the present invention, a preferable polymer from the viewpoint of a high melting point is L-
Polylactic acid, which is a polyester containing lactic acid as a main component, and polyglycolic acid, which is a polyester containing glycolic acid as a main component, can be given.

"L-lactic acid as a main component" means that 60% by weight or more of the constituents are composed of L-lactic acid, and a polyester containing D-lactic acid in an amount not exceeding 40% by weight. It may be.

The method for producing polylactic acid includes a two-stage lactide method in which lactide, which is a cyclic dimer, is first produced using lactic acid as a raw material, and then ring-opening polymerization is performed. Is known as a one-step direct polymerization method. The polylactic acid used in the present invention may be obtained by any production method. In the case of the polymer obtained by the lactide method, since the cyclic dimer contained in the polymer is vaporized at the time of melt spinning and causes thread spots, the cyclic dimer contained in the polymer before the melt spinning is obtained. It is desirable that the content of the body be 0.1 wt% or less. In the case of the direct polymerization method, the cyclic 2
Since there is substantially no problem caused by the polymer, it can be said that the polymer is more preferable from the viewpoint of the spinning property.

The higher the average molecular weight of the polylactic acid, the better, usually at least 50,000, preferably at least 10
And more preferably 100,000 to 300,000. When the average molecular weight is lower than 50,000, the strength physical properties of the fiber tend to decrease.

The polylactic acid in the present invention may be a copolymerized polylactic acid obtained by copolymerizing other components having an ester-forming ability in addition to L-lactic acid and D-lactic acid. Other copolymerizable components include hydroxycarboxylic acids such as glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, and 6-hydroxycaproic acid, as well as ethylene glycol, propylene glycol, and butanediol. , Neopentyl glycol, polyethylene glycol, glycerin, pentaerythritol, and other compounds containing a plurality of hydroxyl groups in the molecule or derivatives thereof, adipic acid, sebacic acid, fumaric acid, terephthalic acid, isophthalic acid, 2,6-naphthalene Examples include compounds containing a plurality of carboxylic acid groups in a molecule such as dicarboxylic acid, 5-sodium sulfoisophthalic acid, and 5-tetrabutylphosphonium isophthalic acid, and derivatives thereof.

In order to reduce the melt viscosity, an aliphatic polyester polymer such as polycaprolactone, polybutylene succinate and polyethylene succinate can be used as an internal plasticizer or as an external plasticizer. Further, inorganic fine particles and organic compounds as a matting agent, a deodorant, a flame retardant, a yarn friction reducing agent, an antioxidant, a coloring pigment and the like can be added as required.

Furthermore, the aliphatic polyester yarn of the present invention comprises an aggregate of aliphatic polyester hollow cross-section single yarns, and each aliphatic polyester hollow cross-section yarn has a thickness defined by the distance between the outer contour and the hollow contour. Should be 3 μm or more, preferably 5 μm or more. This spacing is an important requirement to prevent damage due to tearing or crushing of the hollow portion when the aliphatic polyester yarn is used as a face yarn of a carpet, and has a thickness of 3 μm or more, preferably 5 μm or more. This makes it possible to obtain an aliphatic polyester yarn that does not cause damage even when used for a longer period of time.

The thickness defined by the distance between the outer contour of the hollow cross-section single yarn and the contour of the hollow portion is, for example, in the case of a hollow hollow cross-section yarn, the outer thickness of the hollow cross-section single yarn shown in FIG. It means the thickness (a) consisting of the distance between the contour (A) and the hollow part contour (B).

Similarly, in the case of a Y-shaped hollow section yarn, FIG.
Means the thickness (a) consisting of the distance between the outer contour (A) of the hollow section single yarn and the hollow part contour (B).

If the thickness (a) is less than 3 μm, the compression fatigue resistance and the heat and weather resistance of the crimped aliphatic polyester yarn are extremely reduced, and the aliphatic polyester crimped yarn is not suitable for use as a face yarn of a carpet.

In the aliphatic polyester hollow cross section single yarn of the present invention, the area occupancy of the hollow portion in the single yarn cross section is not particularly limited. A range of 20% is preferred.

The multifilament constituting the aliphatic polyester yarn of the present invention has a total fineness of 500 to 5,000 decitex in consideration of handling at the time of high-order processing as a face yarn of a carpet. .

That is, if the total fineness is less than 500 decitex, it is necessary to increase the density of tufts and the like at the time of carpet processing, and the processing cost increases, and conversely, 5000
Exceeding the decitex is not preferable because the handling during tufting becomes complicated and impractical.

In order to further improve the bulkiness of the aliphatic polyester yarn of the present invention, the outer shape of the aliphatic polyester hollow cross-section single yarn is preferably made of three externally projecting convexes. And three valleys, and one to three hollows, and preferably has a single yarn fineness of 8 to 25 dtex.

That is, FIG. 2 shows the above-mentioned outer shape Y
In the figure, an example of a single yarn having a hollow cross section is shown, in which (C) shows a hollow portion, (D) shows three peaks, and (E) shows three valleys.

As described above, by forming the peaks (D) and the valleys (E), the secondary moment of area of the aliphatic polyester hollow cross-section single yarn is increased, and as a result, the bending recovery is improved. In addition, since the area occupied by each single yarn increases, a carpet face yarn having more elasticity and excellent covering properties can be obtained.

The number of the peaks (D) and the valleys (E) is set to three in consideration of the effect thereof and the ease of spinning when the aliphatic polyester is melted to form a deformed cross section. That is, to make the substantially Y-shaped shape shown in FIG.
Most practical.

Next, the aliphatic polyester yarn of the present invention
From the viewpoint of cost reduction in the production process of a carpet using the same, particularly the requirement of no dyeing, or the point of avoiding a change in physical property value due to dyeing, 0.1 to 3.0% by weight, preferably 0.5 to 2% by weight in the yarn. It is desirable to contain 0.0 weight percent of the colorant.

However, when the content of the coloring agent exceeds 3.0% by weight, there is a tendency that problems such as inducing thread breakage in the filament spinning process and lowering the viscosity of the aliphatic polyester are caused. If the amount is less than 0.1% by weight, there may be a problem that the hue uniformity of the filament is deteriorated and the hue becomes too light.

Examples of the coloring agent usable in the present invention include carbon black, anthraquinone coloring agent, dioxazine coloring agent, phthalocyanine coloring agent, and the like.
Examples include perylene colorants, perinone colorants, condensed azo colorants, thioindigo colorants, titanium dioxide, and iron oxide colorants. Considering disposal, it is most preferable to use a carbon black colorant. The blended carbon black is not particularly limited, but has a particle diameter of 3 in the fiber.
Carbon black having a size of 1 μm or less is preferred, and carbon black having a size of 1 μm or less is particularly preferred. When a coloring aid is used, for example, copper phthalocyanine blue or phthalocyanine blue pigment having 1 chlorine atom substitution: Pigment
Blue 15 and the like.

As a method of adding these colorants, a method of blending and spinning at the time of chip drying, a method of directly adding a colorant at the time of spinning, a method of melting a master chip containing a high concentration of a colorant and separately melting a base polymer are used. Addition techniques such as a method of blending and spinning with (melt blending method) and a method of blending a master chip and a base chip containing a high concentration of a colorant and melt-spinning (chip blending method) can be applied. , Quality stability,
In consideration of operation stability and cost, a method using a master chip is particularly effective.

Next, the carpet of the present invention is an aggregate of the above-described aliphatic polyester yarn for carpet, that is, an aggregate of hollow cross-section single yarns obtained by melt-spinning an aliphatic polyester having a melting point of 145 ° C. or more, Total fineness is 500-5
000 decitex aliphatic polyester multifilament, wherein the hollow cross-section single yarn has a thickness of 3 μm or more, which is the distance between the outer contour and the hollow contour, is a carpet aliphatic polyester yarn. It is configured using.

Here, the processing form of the carpet in the present invention is not limited.
Compression of woven carpets such as Wilton, Double Face, Akisminster, embroidery carpets such as tufting and hook drag, bonded carpets such as bonded, electrodeposited, cords, knitted carpets such as knits and Russells, and compression of needle punches A carpet represented by a carpet or a combination thereof can be used,
In order to obtain a carpet rich in volume at a lower cost, it is preferable to use a tufting carpet composed of at least a face yarn that is a pile fiber yarn and a base fabric obtained by tufting the face yarn.

Further, a preferred form of tufting carpet for improving the effect of reducing environmental load can be achieved by forming a part, preferably 50% or more, of the base fabric with aliphatic polyester fibers.

The carpet of the present invention is installed for various purposes and places, for example, a living room, a kitchen, an entrance,
Dust control, residential use such as veranda, office,
For commercial use such as schools, museums, theaters, hotels, restaurants, banks, department stores, retail stores, etc., for transportation of railways, cars, buses, ships, aircraft, etc., athletics stadiums, baseball stadiums, golf courses, tennis courts, fitness clubs , For indoor and outdoor sports such as poolside, but especially for passenger cars,
It can be suitably used as a carpet for automobiles such as commercial vehicles and buses.

The shape of the face yarn of the carpet of the present invention is not particularly limited. For example, cut pile, loop pile or a combination thereof can be used, and a plurality of aliphatic polyester yarns of the present invention are twisted. May be used, and may be used in combination with other fibers or materials as long as the effect of the aliphatic polyester yarn of the present invention is not impaired.

The carpet of the present invention using the above-mentioned aliphatic polyester yarn as a face yarn has excellent bulky properties and abrasion durability, has a function of enabling weight reduction, and has a function of being discarded after its use. The impact on the environment is extremely small.

In general, aliphatic polyester is a material having a very high biodegradability, and is naturally decomposed even when buried in soil, so that the burden on the environment can be reduced.

When the aliphatic polyester yarn of the present invention contains a coloring agent, it is desirable to use a carbon black coloring agent in consideration of environmental load.

Next, an example of the method for producing the aliphatic polyester yarn and the carpet of the present invention will be described.

First, a base chip of an aliphatic polyester is supplied to an extruder to form a molten aliphatic polyester.
Subsequently, melt spinning is performed from a desired hollow section type spinneret.

When a coloring agent is contained in the aliphatic polyester to be used, for example, an aliphatic polyester master chip containing 10% by weight or more, preferably 15% by weight or more, more preferably 20% by weight or more of the coloring agent is used. It is advisable to mix the dye with the aliphatic polyester base chip by weighing so that the concentration of the colorant in the aliphatic polyester spun yarn is in the range of 0.1 to 3.0% by weight.

The spun yarn is cooled and solidified by cold air, and subsequently, after an oil agent is adhered thereto, it is taken up by a take-up roll.

Further, this undrawn filament is then led to a drawing step, and when a proper crimp is to be applied to the carpet, it is subsequently introduced into a heating fluid crimping apparatus.

As the heating fluid in the crimping step,
It is preferable to use heated steam or heated air.

After the multifilament crimped by the heating fluid is cooled, the multifilament is stretched to such an extent that the crimp does not collapse, and finally wound up in a package.

In any part of the above steps, the filament may be wound once, but is preferably continuously wound.

The aliphatic polyester yarn for carpet of the present invention thus obtained is extremely excellent in stretchability, so that the productivity is stable, the bulky property and the wear resistance are excellent, and the hollow cross section has good covering property. Is good, it is possible to provide a tufting carpet that can be reduced in weight.

Further, the carpet of the present invention is obtained by setting the aliphatic polyester yarn obtained by the above method in, for example, a tufting machine, and using the aliphatic polyester crimped yarn as a face yarn to form a primary polyester nonwoven fabric. After tufting on a cloth or the like, it can be obtained by backing.

In this case, if necessary, steaming, brushing, spraying,
Processing such as dyeing, shearing, and polishing can be performed.

The carpet using the aliphatic polyester yarn for carpet of the present invention is excellent in bulkiness and durability, lightweight, and biodegradable. If it is suitable as a carpet but needs its effect and purpose,
It can be used for carpets other than carpets and other uses.

[0058]

The objects and effects of the present invention will be further described below with reference to examples. The physical property values in the examples described above and below are values obtained as follows. (1) Melting point PerkinElmer's differential scanning calorimeter (DSC-7)
Was measured at a heating rate of 15 ° C./min, and the peak temperature of the obtained melting peak was defined as the melting point. (2) Total fineness Measured according to JIS L 1090. (3) Single yarn fineness The total fineness measured as described above was gradually obtained based on the number of single fibers. (4) Crimp elongation The fiber was subjected to boiling water treatment at 98 ° C. for 5 minutes without load, air-dried, and subjected to an initial load (2 mmg / d), and the length (L)
Measure 1). Next, a constant load (100 mmg / d) was applied, the length (L2) was measured, and calculated by the following equation. Crimp elongation rate (%) = 100 × (L2−L1) / (L1) (5) Hollow rate After cutting the cross section of the single yarn, using an optical microscope, the cross-sectional area of the entire single yarn including the hollow portion (D) And the cross-sectional area (E) of the hollow portion were calculated by the following equation. Hollow ratio (%) = 100 × (E) / (D) [Examples 1 to 4] As shown in Table 1, the melting point was 172 ° C.
The poly L-lactic acid chips (L-form ratio 95%, D-form ratio 5%) were dried in a vacuum dryer set at 60 ° C. for 48 hours, and the dried chips were melted by a pressure melter spinning machine. It was introduced into a melt pack and spun from a spinneret having the pores of a hollow cross-section die.

The filament spun from the spinning section is first coated with an oil agent, subsequently taken up by a take-up roll, and drawn by a heating draw roll to obtain a cross-sectional shape of the single yarn, the number of filaments, and the fineness of the single yarn. In addition, four types of multifilaments having hollow ratios as shown in Table 1 were obtained.

Further, each of the multifilaments is continuously supplied to a crimping apparatus described in Japanese Patent Publication No. 58-1214, and subjected to a heating steam treatment condition at 150 ° C. or more to apply a crimp. As shown in Table 1, the total fineness (total fineness) and the crimp elongation ratio differ by stretching the stretched crimp to such an extent that the crimp does not loosen and finally winding it up with a winding tension of about 0.08 g / denier. Into four types of aliphatic polyester yarns.

In Examples 3 and 4, a polylactic acid chip containing 10% by weight of carbon black was weighed and mixed at a weight ratio of 1/40 with respect to the base chip, and then spun by the above method. It was stretched and wound up.

At this time, the stretchability was evaluated, and
As the raw yarn characteristics of the obtained aliphatic polyester multifilament yarn, the results of measuring the crimp elongation, the hollow ratio, and the thickness (a) consisting of the interval between the outer contour of the hollow cross-section single yarn and the contour of the hollow portion described above were measured. Are also shown in Table 1. Here, the evaluation of the stretchability in Table 1 is based on the following criteria.

・ ・ ・: Extremely good ○: Good ×: Poor Further, each aliphatic polyester yarn obtained above was used as a face yarn, and the basis weight of the aliphatic polyester nonwoven fabric was 800 g / m ^2. Was tufted as a cut pile carpet.

As the characteristics of each tufting carpet thus obtained, the bulky property, abrasion resistance and carburizing property of the carpet surface were evaluated according to the following criteria. The results are shown in Table 1. <Evaluation criteria for carpet> ◎ ・ ・ ・ Very good ○ ・ ・ ・ Good △ ・ ・ ・ Somewhat bad × ・ ・ ・ Poor

[0065]

[Table 1]

As is evident from the results in Table 1, the aliphatic polyester yarns of Examples 1 to 4 have extremely excellent drawability, and physical properties such as crimp elongation and bulkiness are different from those of carpet. It was a very good yarn.

Further, the tufting carpet obtained by using each of the above-mentioned aliphatic polyester yarns was excellent in bulk elasticity and covering property and excellent in abrasion durability since it was rich in compression elasticity. .

After the carpet was buried in the soil for 800 days and taken out, the face yarn and the base fabric were deteriorated, and high biodegradability was recognized. [Comparative Examples 1 to 3] Table 2 was prepared in the same manner as in Example 1 using aliphatic polyester base chips having different melting points.
As shown in the above, three kinds of aliphatic polyester yarns having different total fineness (total fineness), the number of filaments, the cross-sectional shape, the hollow ratio, the crimp elongation ratio, and the thickness (a) are manufactured, In addition, three kinds of carpets obtained by tufting a polypropylene woven base fabric using these aliphatic polyester yarns as face yarns were obtained.

Table 2 also shows the results of the same evaluations as in the above examples performed on each aliphatic polyester yarn and carpet.

[0070]

[Table 2]

As is clear from the results in Table 2, Comparative Example 1
Since polybutylene succinate is used as a polymer, the melting point of the aliphatic polyester is as low as 110 ° C., so that the stretchability is extremely poor and the abrasion resistance of the carpet is also poor.

Similarly, in Comparative Example 2, since the thickness (a) defined by the distance between the outer contour of the hollow cross-section single yarn and the outline of the hollow portion was less than 3 μm, not only the drawability of the original yarn was poor, but also the carpet During use, the hollow portion was broken by abrasion, and the fibers were fibrillated, resulting in poor abrasion resistance.

Further, in Comparative Example 3, since the yarn had a round cross-section without a hollow portion, not only the crimp elongation rate of the original yarn was low, but also the bulkiness was poor, and the carpet was poor in bulky property and covering property. Met.

[0074]

As described above, the aliphatic polyester yarn for carpet of the present invention has a stable productivity, bulkiness and abrasion because the melting point, cross-sectional shape and cross-sectional dimensions of the aliphatic polyester are specified. Excellent durability,
In addition, because of good covering properties, a carpet that can be reduced in weight can be provided.

Further, the carpet of the present invention has excellent covering properties, bulkiness and durability, and is lightweight and biodegradable. is there.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an aliphatic polyester yarn (a hollow hollow cross-section yarn) according to the present invention cut in a cross-sectional direction.

FIG. 2 shows an aliphatic polyester yarn (Y) according to the present invention.
FIG. 2 is a cross-sectional view of a hollow cross-sectioned yarn (a cross-section yarn) cut in a cross-sectional direction.

[Explanation of symbols]

(A) Outer contour of hollow section single thread (B) Hollow section contour of hollow section single thread (a) Thickness consisting of the distance between outer contour of hollow section single thread and hollow section contour (C) Hollow section single thread Hollow section (D) Crest section of hollow section single thread (E) Valley section of hollow section single thread

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D01F 6/92 301 D01F 6/92 301M D04H 11/00 D04H 11/00 F-term (Reference) 3B120 AA19 AA42 EA10 EB15 EB16 4L035 BB31 CC20 DD03 DD05 EE01 FF01 JJ03 JJ10 4L047 AA21 AB03 AB09 CB10 CC09 CC10 CC16

Claims (8)

[Claims] A hollow cross-section single yarn aggregate obtained by melt-spinning an aliphatic polyester having a melting point of 145 ° C. or more, comprising an aliphatic polyester multifilament having a total fineness of 500 to 5,000 decitex, wherein said hollow cross-section is An aliphatic polyester yarn for carpets, wherein the single yarn has a thickness defined by a distance between an outer contour and a hollow portion contour of 3 μ or more. 2. The hollow cross-section single yarn has an outer shape formed by three peaks and three valleys protruding to the outside, and has one to three hollows in the axial direction of the fiber. The aliphatic polyester yarn for carpet according to claim 1, characterized in that: 3. The polyester yarn for carpet according to claim 1, wherein the aliphatic polyester multifilament contains 0.1 to 3.0% by weight of a coloring agent. 4. The aliphatic polyester yarn for carpet according to claim 3, wherein the coloring agent is a carbon black coloring agent. 5. The aliphatic polyester yarn for carpet according to claim 1, wherein the area occupancy of the hollow portion in the cross section of the single yarn is in the range of 5 to 20%. 6. The aliphatic polyester yarn for carpet according to claim 1, wherein the fineness of the single yarn is 8 to 25 decitex. 7. A carpet using the aliphatic polyester yarn for carpet according to claim 1 as a face yarn. 8. The carpet according to claim 7, wherein the carpet is used for an automobile carpet.