JP2002302833A - Polyester-based thermoadhesive conjugate fiber and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester-based thermoadhesive conjugate fiber composed of a polyalkylene terephthalate as the fiber-forming component and a noncrystalline polyester as the thermoadhesive component, and capable of giving a high-grade fibrous structure with good dimensional stability hard to cause its deformation even if used in a high-temperature atmosphere, and to provide a method for producing the above conjugate fiber. SOLUTION: This polyester-based thermoadhesive conjugate fiber is composed of a thermoadhesive component consisting of a noncrystalline polyester 50-100 deg.C in glass transition point having no crystal melting point and a fiber-forming component consisting of a polyalkylene terephthalate >=220 deg.C in melting point. This conjugate fiber has the number of crimps of 3-40/25 mm, crimp percent of 3-40%, and web area shrinkage of <=20%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester-based heat-adhesive conjugate fiber suitable for bonding a fibrous structure such as a nonwoven fabric or a wadding and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a polyester-based heat-adhesive conjugate fiber has a polyalkylene terephthalate such as polyethylene terephthalate (PET) as a core component and does not have a crystalline melting point composed of an isophthalic acid component or a terephthalic acid component. Fibers having an amorphous polyester-based polymer as a sheath component are widely used because they can be heat-fixed at a relatively low temperature of 120 to 150 ° C. and can form a fibrous structure without requiring high-temperature heat treatment.

[0003] However, the above-mentioned polyester-based thermo-adhesive conjugate fibers can be formed into a fiber structure at a relatively low temperature as described above, but when the fiber structure is used in a high-temperature atmosphere, the dimensional stability is poor. There is a problem that deformation is large.

The present inventors have attempted to draw or heat-treat at a high temperature in order to improve the dimensional stability of the heat-bondable fiber itself in order to solve such a problem. At a temperature higher than the point transfer, the fibers stuck together, and it became clear that there was a problem that the yarn production became difficult.

[0005] Under these circumstances, a heat-adhesive conjugate fiber having excellent dimensional stability using an amorphous polyester, particularly an amorphous polyester having a glass transition point of 50 to 100 ° C, as a heat-adhesive component has not yet been developed. The fact is that it has not been proposed.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a polyester composite fiber comprising a polyalkylene terephthalate as a fiber-forming component and an amorphous polyester having a glass transition point of 50 to 100 ° C. as a heat bonding component. An object of the present invention is to provide a polyester-based heat-adhesive conjugate fiber which has good dimensional stability, hardly deforms even when used in a high-temperature atmosphere, and can obtain a high-quality fiber structure, and a method for producing the same. I do.

[0007]

According to the study of the present inventors, it has been found that the above-mentioned object can be achieved by the following polyester-based heat-adhesive conjugate fiber and its production method.

That is, according to the present invention, an amorphous polyester having a glass transition point of 50 to 100 ° C. and having no crystalline melting point is used as a heat bonding component, and a polyalkylene terephthalate having a melting point of 220 ° C. or more is used as a fiber forming component. Wherein the number of crimps of the composite fiber is 3 to 40.
The polyester-based heat-adhesive conjugate fiber is characterized in that the polyester-based heat-adhesive conjugate fiber has a ratio of pieces / 25 mm, a crimp rate of 3 to 40%, and a web area shrinkage rate defined below of 20% or less. Consisting <Web area shrinkage percentage> thermally bonding conjugate fibers of 100%, the area is A _0, the basis weight of the carded web nonwoven 30 g / m ^2, for 2 minutes in a hot air dryer maintained at 0.99 ° C., then of measuring the area a ₁ of the nonwoven fabric was determined from the following equation. Web area shrinkage (%) = (A ₀ −A ₁ ) / A ₀ × 100

An amorphous polyester having a glass transition point of 50 to 100 ° C. and having no crystalline melting point;
The above-mentioned polyalkylene terephthalate is compounded and melt-discharged, the discharged yarn is drawn at a speed of 1500 m / min or less to form an undrawn conjugate fiber, and then the polyether polyester copolymer is added to the undrawn conjugate fiber. T ₁ ~ (T ₂ after the application of 0.03 wt% or more based on the fiber weight +30
C) at a temperature of 0.72 to 1.25 times the maximum stretching ratio when cold, and further crimped so that the number of crimps is 3 to 40 pieces / 25 mm and the crimp rate is 3 to 40%. And a method for producing a polyester-based heat-adhesive conjugate fiber, which is provided. Here, T ₁ is the higher of the glass transition point of the amorphous polyester and the glass transition point of the polyalkylene terephthalate, and T ₂ is the glass transition point of the amorphous polyester.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The conjugate fiber of the present invention requires the use of polyalkylene terephthalate having a melting point of 220 ° C. or higher as a fiber-forming component. When the melting point of the polyester as the fiber-forming component is lower than 220 ° C., not only is it difficult to stably produce the conjugate fiber, but also the stability during the heat bonding treatment is reduced. As a specific example of the polyalkylene terephthalate, PET or polybutylene terephthalate (PBT) is preferable, and a small amount of a copolymer component and additives such as a matting agent, a coloring agent, and a lubricant are contained as long as the properties are not impaired. May be. Among them, polyethylene terephthalate is more preferable because it is inexpensive and widely used.

On the other hand, as the amorphous polyester serving as the heat bonding component, a polyester having a glass transition point of 50 to 100 ° C. and having no crystalline melting point is used. When the glass transition point is lower than 50 ° C., the fibers are liable to stick together at the time of stretching even in the production method described later, and it is not possible to obtain a conjugate fiber having an area shrinkage of 20% or less and excellent dimensional stability. . On the other hand, if the glass transition point exceeds 100 ° C., the heat fixation at low temperatures such as 120 to 150 ° C. deteriorates, which is not preferable.

[0012] As such an amorphous polyester,
For example, an acid component such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid, azelaic acid, dodecanoic acid, 1,4-cyclohexanedicarboxylic acid, and ethylene glycol , 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, diethylene glycol,
Examples include random or block copolymers of diol components such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol. Among them, amorphous copolyesters, which are conventionally widely used and are composed of a terephthalic acid component, an isophthalic acid component, an ethylene glycol component and a diethylene glycol component, are preferred in view of cost and handleability.

When a copolyester comprising a terephthalic acid component, an isophthalic acid component, an ethylene glycol component and a diethylene glycol component as described above is used as the heat bonding component, the glass transition point should be within the above range. Although it is necessary to select, the molar ratio of the terephthalic acid component to the isophthalic acid component is 50:50 to 80: 2.
A range of 0 is suitable, while the molar ratio of ethylene glycol to diethylene glycol is from 0: 100 to 100: 0.
Can be selected arbitrarily.

The heat-adhesive conjugate fiber of the present invention has a core as long as the heat-adhesive component occupies all or a part of the surface of the single fiber (preferably 40% or more, particularly 60% or more of the fiber surface area). Any of composite forms such as a sheath type, an eccentric core-sheath type, a side-by-side type, a sea-island type, a split type, and the like may be adopted.
Among them, the core-sheath type, the eccentric core-sheath type, and the side-by-side type are more preferable.

Next, the thermoadhesive conjugate fiber of the present invention needs to have a crimp number of 3 to 40/25 mm and a crimp rate of 3 to 40%. When the number of crimps is less than 3 pieces / 25 mm or the crimp rate is less than 3%, the entanglement between short fibers is insufficient, the card passing property is deteriorated, and a high-quality fiber structure cannot be obtained. Not preferred. On the other hand, the number of crimps is 40/25
If the diameter exceeds 0.1 mm or the crimp ratio exceeds 40%, the entanglement between short fibers becomes too large, so that carding cannot be performed sufficiently with a card, and a high-quality fiber structure cannot be obtained. It is not preferable. More preferably, the number of crimps is 5 to 30 crimps / 25 mm, and the crimp rate is 5
-30%. The form of the crimp may be a mechanical crimp or a three-dimensional crimp, and may be appropriately selected and set according to the use or purpose.

In the heat-adhesive conjugate fiber of the present invention, in addition to the above-mentioned requirements, the web area shrinkage defined below is 2
It is essential that the content is 0% or less, whereby a fiber structure having excellent dimensional stability even under a high-temperature atmosphere can be obtained by mixing the conjugate fiber with 100% or other fibers. If the shrinkage exceeds 20%, a fiber structure excellent in dimensional stability under a high-temperature atmosphere cannot be obtained. A more preferable web area shrinkage rate is 10% or less.

<Web area shrinkage> The above heat-fusible fiber 1
A card web nonwoven having an area of A ₀ and a basis weight of 30 g / m ² was left in a hot air dryer maintained at 150 ° C. for 2 minutes, and the area A ₁ of the nonwoven was measured. I asked more. Web area shrinkage (%) = (A ₀ −A ₁ ) / A ₀ × 100

The above-mentioned polyester-based heat-adhesive conjugate fiber of the present invention can be efficiently produced by, for example, the following method. That is, the above-mentioned amorphous polyester and polyalkylene terephthalate are compounded, preferably compounded into a core-sheath type, an eccentric core-sheath type, and a side-by-side type and melt-discharged, and the discharged yarn is taken at a speed of 1500 m / min or less. undrawn conjugate fibers and without Te, then, T ₁ after a polyether polyester copolymer was applied 0.03 wt% or more based on the fiber weight unstretched composite fibers -
(T ₂ + 30 ° C.) 0.72 of the maximum stretching ratio when cooled at a temperature of
Stretched to 1.25 times, and the number of crimps is 3 to 40/2
It can be manufactured by giving a crimp so as to have a crimp rate of 5 mm and a crimp rate of 3 to 40%. Here, T ₁ is the higher of the glass transition point of the amorphous polyester and the glass transition point of the polyalkylene terephthalate, and T ₂ is the glass transition point of the amorphous polyester.

Here, when the take-off speed exceeds 1500 m / min, the web surface shrinkage cannot be reduced to 20% or less even if the obtained composite unstretched fiber is stretched under the above-mentioned conditions. Absent.

The first point of the production method according to the present invention is to apply a polyether polyester copolymer to the surface of the composite fiber before drawing the undrawn composite fiber. is there. In this way, even if the film is stretched at a temperature higher than or equal to the glass transition point T ₂ of the amorphous polyester (that is, corresponding to the softening point of the amorphous copolymerized polyester), the stretching temperature is not higher than T ₂ + 30 ° C. If so, a polyester-based composite fiber having a web surface shrinkage of 20% or less can be obtained without causing inter-fiber sticking in the drawing step. Moreover, even if the polyether polyester copolymer adheres to the surface of the conjugate fiber, the thermal adhesiveness does not decrease so much, so that a fiber structure having excellent mechanical properties can be obtained.

The simultaneous achievement of the anti-sticking effect and the effect of maintaining the thermal adhesiveness can be achieved by using an anionic surfactant or a polyoxyalkylene adduct thereof, a cationic surfactant generally used as an oil agent for producing short fibers. Surfactants, nonionic surfactants other than polyether polyester copolymers, mineral oils and the like cannot be used, and polysiloxane-based processing agents cannot.

Such a polyether polyester copolymer particularly contains a terephthalic acid component and an isophthalic acid component and / or an alkali metal salt sulfoisophthalic acid component as a dicarboxylic acid component in a molar ratio of 40:60 to 100: 0. A copolymer obtained by copolymerizing 20 to 95% by weight of a polyalkylene glycol having a glycol component of ethylene glycol and a number average molecular weight in the range of 600 to 10000 is used for the stability of the aqueous emulsion and the prevention of sticking during the stretching step. It is preferable from the point of effect. However, adipic acid, sebacic acid, azelaic acid, dodecanoic acid, 1,4
Acid components such as cyclohexanedicarboxylic acid,
-Propanediol, 1,4-butanediol, 1,5
-Pentanediol, 1,6-hexanediol, diethylene glycol, 1,4-cyclohexanediol,
A small amount of a diol component such as 1,4-cyclohexanedimethanol may be copolymerized, and one end group of the polyalkylene glycol may be monomethyl ether, monoethyl ether, monophenyl ether in order to adjust the molecular weight. And it may be blocked by an ether bond. On the other hand, examples of the polyalkylene glycol include polyethylene glycol, ethylene oxide / propylene oxide copolymer, polypropylene glycol, polytetramethylene glycol, and the like. Among them, polyethylene glycol is preferable.

The number average molecular weight of the polyether polyester copolymer is preferably in the range of 3,000 to 20,000 because a higher anti-sticking effect can be obtained.

The amount of the polyether polyester copolymer adhering to the undrawn fibers must be at least 0.03% by weight based on the undrawn fibers.
When the amount is less than% by weight, a sufficient anti-sticking effect cannot be obtained during stretching described below, which is not preferable.

The method for adhering the above-mentioned polyether polyester copolymer to the surface of the undrawn conjugate fiber is not particularly limited, and it can be applied by any method, but is usually applied as an aqueous emulsion solution. At that time, in addition to the emulsifier for stabilizing the emulsion solution, an antistatic agent,
Additives such as a leveling agent, a rust inhibitor, a fungicide, and an antibacterial agent may be included, and the second point in the above production method is the stretching temperature. The stretching temperature is, of course, set to T ₂ (glass transition point of amorphous polyester) or more, but at the same time, in order to heat-fix the polyalkylene terephthalate, which is a fiber-forming component, the polyalkylene terephthalate is used. It is necessary to set the temperature at or above the glass transition point. Even if a polyether polyester copolymer has been previously applied to the undrawn conjugate fiber surface, if the drawing temperature is lower than one of the glass transition points of the amorphous copolymerized polyester and the polyalkylene terephthalate, A heat-adhesive conjugate fiber having excellent dimensional stability, which is the object of the present invention, cannot be obtained. Furthermore, it is important not to set the stretching temperature to a high temperature exceeding T ₂ (glass transition point of amorphous polyester) + 30 ° C. If the stretching temperature exceeds T ₂ + 30 ° C., the sticking of the amorphous polyester cannot be sufficiently prevented, and a fusion fiber bundle is generated or the crimper stability when crimping is applied by a press crimper is insufficient. It is not preferable because it deteriorates.

If the stretching temperature is within the above range, the stretching may be one-stage stretching or two or more stages stretching, but it is necessary that the total stretching ratio be 0.72 to 1.25 times the cold stretching ratio. is there. When the stretching ratio is less than 0.72 times the cold stretching ratio, the dimensional stability of the fiber structure is reduced, while when the stretching ratio exceeds 1.25 times the cold stretching ratio, the stretchability is poor. This is not preferred because it not only deteriorates, but also lowers the thermal adhesion. The cold drawing ratio of the undrawn fiber as referred to herein means that the undrawn conjugate fiber collected within 5 minutes from immediately after spinning is heated at 25 ° C.
The film is stretched in air at a relative humidity of 65% at a speed of 5 cm / sec with a chuck length of 10 cm.
m).

[0027] In the present invention, the above stretching, T ₁ to (either higher temperature among the glass transition point of the glass transition point and a polyalkylene terephthalate amorphous copolymerizable polyester) (T ₁ + 10 ℃) After drawing at a temperature of 0.7 to 1.0 times the cold drawing ratio of the undrawn composite fiber, (T ₁ +
Stretching 1.03 to 1.25 times at a temperature of (10 ° C.) to (T ₂ (glass transition point of amorphous copolymerized polyester) + 30 ° C.) is effective for further improving dimensional stability. This is more effective in preventing sticking. Note that it is particularly effective to use warm water as the stretching heating medium.

The stretched composite fiber has a crimp number of 3 to 40/25 mm and a crimp rate of 3 to 4 by a conventionally known method.
A crimp is applied under the condition of 0%. That is, for example, when the crimping form is mechanical crimping, for example, a press-type crimper may be used, and the conditions of the press-in pressure and temperature may be appropriately controlled. On the other hand, in the case of three-dimensional crimping, a composite structure of the composite fiber may be selected, or cooling conditions during spinning may be selected.

The thus obtained heat-adhesive conjugate fiber of the present invention has good dimensional stability and is suitable for use in fibrous structures such as nonwoven fabric and hard cotton. Such a heat-adhesive conjugate fiber may be used alone as a fiber structure such as a nonwoven fabric, or another fiber may be used as a main fiber and mixed with the heat-adhesive conjugate fiber to form a fiber structure such as a nonwoven fabric.

[0030]

EXAMPLES Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, each evaluation in an Example was performed by the following method. (A) Glass transition point (Tg), melting point (Tm) Measurement was carried out at a heating rate of 20 ° C./min using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer. (B) Intrinsic viscosity ([η]) Measured at a temperature of 35 ° C. using orthochlorophenol as a solvent. (C) Number of crimps and crimp rate Measured according to the method described in JIS L 1015 7.12. (D) Fineness The fineness was measured by the method described in JIS L 1015 7.5.1 A method. (E) Fiber length Measured by the method described in JIS L 1015 7.4.1 C method. (F) Adhesion of oil agent The weight of the residue extracted from the fiber with methanol at 30 ° C for 10 minutes at a bath ratio of 1:20 was measured for the predetermined fiber weight, and the value obtained by dividing by the predetermined fiber weight was used. (G) Shrinkage rate of web area and deformation of fibrous structure, basis weight 30 g / m ² , area A ₀ (25 × 25 cm = 625c)
m ² ) A card web composed of 100% of the heat-adhesive conjugate short fibers is molded and heated at 150 ° C. with a hot air dryer (hot air circulating constant temperature dryer manufactured by Satake Chemical Machinery Co., Ltd .: 4).
1-S4) for 2 minutes in, was determined areal shrinkage by the following formula from the area A ₂ of the heat treatment after the card web. In addition, the thing whose area shrinkage rate is 20% or less was set as the pass. Area shrinkage rate (%) = (625-A ₁ ) / 625 × 100 (h) Glue When agglutination occurs during stretching and production is impossible or when glue binding is confirmed in the card web, it is regarded as bad, otherwise it is good And

Example 1 PET having an intrinsic viscosity of 0.64, Tg of 67 ° C. and Tm of 256 ° C. as a fiber-forming component, a terephthalic acid component: isophthalic acid component = 60: 40 in molar ratio of an acid component as a thermal bonding component, and a diol After using amorphous copolymerized polyester having an intrinsic viscosity of 0.56 and Tg of 64 ° C. in which the components were copolymerized in a molar ratio of ethylene glycol: diethylene glycol = 95: 5, each pellet was dried under reduced pressure, and then dried. The mixture was supplied to a mold composite melt spinning apparatus, and was melt-spun from a spinneret having 450 spinning holes at a spinning temperature of 290 ° C. and a discharge rate of 650 g / min at a composite ratio of 50/50 by volume. The spun yarn is cooled with cold air at 30 ° C., and as a spinning oil, polyethylene having a molar ratio of an terephthalic acid component: isophthalic acid component = 80/20, a glycol component of ethylene glycol, and a number average molecular weight of 3,000 as a molar ratio. The number average molecular weight of copolymerized with 70% by weight of glycol is 1000
An emulsion of the polyether polyester copolymer of No. 0 was applied using an oiling roller so that an oil agent adhesion rate was 0.1% by weight, and the emulsion was taken out at 900 m / min to obtain an undrawn core-sheath type conjugate fiber. The maximum draw ratio of the undrawn fiber at the time of cooling (hereinafter, referred to as CDR) was 4.5 times.

The undrawn fibers are bundled and 110,000 dtex
(100,000 denier), first stretched 3.5 times (0.78 times CDR) in warm water at 72 ° C.
The film is further stretched 1.15 times in warm water at ℃ (total stretching ratio of 4.
0: 0.89 times the CDR) and a spinning oil agent comprising lauryl phosphate potassium salt, and then crimped by a push-in crimper naturally cooled to 35 ° C., and cut into a fiber length of 51 mm. Single yarn fineness 4.4dtex
Was obtained. The number of crimps at this time is 10
Individual pieces / 25 mm, crimp rate was 15%.

[Examples 2 to 10, Comparative Examples 1 to 6] The same conditions as in Example 1 were used except that the heat bonding component, the fiber-forming component, the spinning oil, the stretching ratio and the stretching temperature were changed. .4 dtex, fiber length 51 mm, number of crimps 10/25
mm, a heat-bondable conjugate short fiber having a crimp rate of 15% was obtained.

Table 1 shows the fiber constitutions of these Examples and Comparative Examples, Table 2 shows the spinning oil composition, and Table 3 shows the spinning stretching conditions and the fiber evaluation results.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

According to the heat-adhesive conjugate fiber of the present invention, dimensional stability is good even though it can be formed into a fibrous structure at a relatively low temperature, and the fiber is deformed even when used in a high-temperature atmosphere. It is possible to provide a high-quality fiber structure that is unlikely to occur. Further, according to the production method of the present invention, the above-mentioned heat-adhesive conjugate fiber can be produced stably without causing sticking.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D04H 1/54 D04H 1 / 54H D06M 15/507 D06M 15/507 Z F-term (Reference) 4L033 AA07 AB01 AC11 AC15 CA46 4L036 MA05 MA15 MA33 PA03 PA36 RA04 RA10 4L041 AA07 AA19 AA20 BA02 BA05 BA21 BC04 BD03 BD10 BD11 CA06 CA11 DD01 DD05 DD15 4L047 AA21 AA27 AB02 AB09 BA05 BA09 BB06 CC07

Claims (7)

[Claims] 1. A heat-adhesive composite comprising an amorphous polyester having a glass transition point of 50 to 100 ° C. and having no crystalline melting point as a heat-adhesive component, and a polyalkylene terephthalate having a melting point of 220 ° C. or higher as a fiber-forming component. In the fiber,
Polyester-based thermal adhesiveness, wherein the number of crimps of the conjugate fiber is 3 to 40/25 mm, the crimp rate is 3 to 40%, and the web area shrinkage rate defined below is 20% or less. Composite fiber. Consisting <Web area shrinkage percentage> thermally bonding conjugate fibers of 100%, the area is A _0, the basis weight of the carded web nonwoven 30 g / m ^2, for 2 minutes in a hot air dryer maintained at 0.99 ° C., then of measuring the area a ₁ of the nonwoven fabric was determined from the following equation. Web area shrinkage (%) = (A ₀ −A ₁ ) / A ₀ × 100 2. The polyester thermoadhesive conjugate fiber according to claim 1, wherein the polyether polyester copolymer adheres to the surface of the polyester thermoadhesive conjugate fiber in an amount of 0.005% by weight or more based on the weight of the fiber. . 3. The polyester-based thermal adhesive according to claim 1, wherein the thermal adhesive component is an amorphous copolymer polyester composed of an isophthalic acid component, a terephthalic acid component, an ethylene glycol component, and a diethylene glycol component. Composite fiber. 4. The polyester thermoadhesive conjugate fiber according to claim 1, wherein the fiber-forming component is polyethylene terephthalate. 5. An amorphous polyester having a glass transition point of 50 to 100 ° C. and no crystalline melting point, and a melting point of 220.
C. or higher and a polyalkylene terephthalate is composited and melt-discharged, the discharged yarn is drawn at a speed of 1500 m / min or less to form an undrawn composite fiber, and then a polyether polyester copolymer is added to the undrawn composite fiber. T ₁ ~ (T ₂ +3 after the application 0.03 wt% or more based on the fiber weight
0 ° C.) at a temperature of 0.72 to 1.25 as the maximum draw ratio when cold.
A method for producing a polyester-based heat-adhesive conjugate fiber, characterized in that the fiber is drawn twice, and crimped so that the number of crimps is 3 to 40/25 mm and the crimp ratio is 3 to 40%.
Here, T ₁ is the higher of the glass transition point of the amorphous polyester and the glass transition point of the polyalkylene terephthalate, and T ₂ is the glass transition point of the amorphous polyester. 6. Stretching is carried out at a temperature of T ₁ to (T ₁ + 10 ° C.) to 0.70 to 1.00 times the maximum stretching ratio at cold temperature, and further at (T ₁ + 10 ° C.) to (T ₂ + 30 ° C.). C) at a temperature of 1.0
The method for producing a polyester-based heat-adhesive conjugate fiber according to claim 5, which is a two-stage drawing in which the drawing is performed at a ratio of 3-1.25 times. 7. The method according to claim 5, wherein the heating medium used for drawing is hot water.