KR100510156B1 - Polyester based thermally adhesive composite short fiber and process for producing the same - Google Patents

Abstract

Polyester-based heat-adhesive composite short fibers, which have good dimensional stability and can obtain a high quality fiber structure that does not easily deform even when used in a high-temperature atmosphere, are amorphous having a glass transition point of 50 to 100 ° C. and no crystal melting point. The number of crimps is 3-40 pieces / 25mm, the crimp rate is 3-40%, and the web area shrinkage rate makes polyester as a heat-adhesive component, and makes polyalkylene terephthalate whose melting point is 220 degreeC or more as a fiber formation component. It has a characteristic of 20% or less.

However, the web area shrinkage rate (%) is maintained at 150 ° C. with a card web non-woven fabric having an area of 100% of heat-adhesive composite short fiber A ₀ and a weight of 30 g / m 2 per unit area. allowed to stand 2 minutes in a hot air dryer, and when the area a ₁ of the subsequent non-woven fabric, - is represented by _{(a 0 a 1) / a} 0 × 100.

Description

Polyester-based heat-adhesive composite short fibers and its manufacturing method {POLYESTER BASED THERMALLY ADHESIVE COMPOSITE SHORT FIBER AND PROCESS FOR PRODUCING THE SAME}

The present invention relates to a polyester-based heat-adhesive composite short fiber suitable for bonding a fiber structure such as a nonwoven fabric or a cotton wool, and a method for producing the same. More specifically, the present invention relates to a heat-adhesive composite short fiber which can be heat-bonded at a relatively low temperature and stably obtains a fiber structure having good dimensional stability, and a method for producing the same.

Conventionally, as polyester-based heat-adhesive composite fibers, there is a non-crystalline non-crystalline melting point having polyalkylene terephthalate such as polyethylene terephthalate as a core component and an isophthalic acid component, a terephthalic acid component, or the like as a constituent acid component. It is widely used in the point that the composite fiber which uses a non-polyester as a sheath component can heat-settle at 120-150 degreeC comparatively low temperature, and can shape a fiber structure, without requiring high temperature heat processing.

However, the polyester-based heat-adhesive composite fiber has a problem in that the fiber structure can be molded at a relatively low temperature, while the obtained fiber structure is used under a high temperature atmosphere, resulting in poor dimensional stability and large deformation.

The present inventors attempted to perform stretching or heat treatment at high temperature in order to improve the dimensional stability of the heat-adhesive fiber itself to solve this problem, but at the temperature above the glass transition point of the amorphous polyester, fibers are interlaced and sacrificed. Proved to be a difficult problem.

Under these circumstances, it has not been proposed until now that the thermally stable composite fiber having amorphous polyester having a glass transition point of 50 to 100 ° C. as the heat adhesive component has excellent dimensional stability.

It is an object of the present invention to be heat-sealable at a relatively low temperature without the need for high temperature heat treatment, and to have good dimensional stability even when used in a high temperature atmosphere, so that deformation does not easily occur, and high-quality nonwoven fabrics and filling cotton, etc. It is to provide a polyester-based heat-adhesive composite short fibers capable of obtaining a fiber structure and a method for producing the same.

MEANS TO SOLVE THE PROBLEM In order to achieve the said objective, the present inventors make amorphous polyester which has a glass transition point of 50-100 degreeC as a heat-adhesive component, selects polyalkylene terephthalate as a fiber forming component, and selects the heat-extending conditions. It has been found to be effective to complete the present invention.

That is, the polyester-based heat-adhesive composite short fibers of the present invention, which can achieve the above object, have a non-crystalline polyester having a glass transition point of 50 to 100 ° C and no crystal melting point as a heat-adhesive component, and the melting point A heat-adhesive composite short fiber comprising, as a fiber-forming component, a polyalkylene terephthalate having a temperature of 220 ° C. or higher, wherein the number of crimps is 3-40 pieces / 25 mm, the crimp rate is 3-40%, and the web area shrinkage defined below. It is characterized by being 20% or less.

<Web area shrinkage>

A card web non-woven fabric having an area A ₀ and a weight of 30 g / m 2 per unit area consisting of 100% of heat-adhesive composite short fibers was allowed to stand for 2 minutes in a hot air dryer kept at 150 ° C. The area A ₁ of the nonwoven fabric after that is measured and calculated | required by the following formula.

Web area shrinkage (%) = (A ₀ -A ₁ ) / A ₀ × 100

Moreover, the manufacturing method of the polyester type heat-adhesive composite short fiber which is another objective of this invention is a non-crystalline polyester which has a glass transition point of 50-100 degreeC, and does not have a crystalline melting point, and the polyalkylene terephthalate whose melting point is 220 degreeC or more. After melt-and-composite discharge and cooling and solidifying this composite discharge yarn, it pulls out at the speed of 1500 m / min or less, and makes it an unstretched composite fiber, Then, the polyether polyester block copolymer is mentioned to this unstretched composite fiber. after granted higher than 0.03% by weight based on the fiber weight T ₁ ~ number _{(T 2 + 30 ℃) 0.72} ~ 1.25 times the stretch, and up to the draw ratio during the cooling at a temperature of 3-40 crimps / 25㎜, the crimp ratio is 3 Crimping is provided so that it may become-40%.

Herein, T ₁ is the temperature of either the glass transition point of the amorphous polyester or the glass transition point of the polyalkylene terephthalate, and T ₂ is the glass transition point of the amorphous polyester.

Best Mode for Carrying Out the Invention

As the fiber-forming component of the polyester-based heat-adhesive composite short fibers of the present invention, a polyalkylene terephthalate having a melting point of 220 ° C. or more is used. When melting | fusing point of polyester which is a fiber formation component becomes less than 220 degreeC, not only it becomes difficult to stably produce a composite fiber, but also the stability at the time of a heat bonding process falls. As a specific example of polyalkylene terephthalate, polyethylene terephthalate or polybutylene terephthalate is preferable, and if it is a range which does not impair these characteristics, it may contain a small amount of additives, such as a copolymerization component, a gloss remover, a coloring agent, a lubricating agent. . Among them, polyethylene terephthalate is more preferable because it is inexpensive and general purpose.

On the other hand, as amorphous polyester which becomes a heat-adhesive component, polyester which has a glass transition point of 50-100 degreeC and does not have a crystalline melting point is used. When the glass transition point of this polyester is less than 50 degreeC, it is unpreferable since the fiber tends to interlock at the time of extending | stretching the below-mentioned manufacturing method, and the composite fiber excellent in the dimensional stability whose area shrinkage is 20% or less cannot be obtained. On the other hand, when a glass transition point exceeds 100 degreeC, since the heat setability in the low temperature of 120-150 degreeC will worsen, it is unpreferable.

Such amorphous polyesters include, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, 1, Acid components such as 4-cyclohexanedicarboxylic acid, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, 1, Random or block copolymers of diol components, such as 4-cyclohexanediol and 1, 4- cyclohexane dimethanol, are mentioned. Especially, amorphous co-polyester comprised from a terephthalic acid component, an isophthalic acid component, an ethylene glycol component, and a diethylene glycol component is preferable from a cost point or a handleability viewpoint.

As a heat-adhesive component, when using the copolyester which consists of the said terephthalic acid component, the isophthalic acid component, the ethylene glycol component, and the diethylene glycol component, it is necessary to set a copolymerization ratio so that a glass transition point may exist in the said range, but a terephthalic acid component The molar ratio of the isophthalic acid component is in the range of 50:50 to 80:20, while the molar ratio of ethylene glycol and diethylene glycol can be arbitrarily selected in the range of 0: 100 to 100: 0.

In the polyester-based heat-adhesive short fibers of the present invention, if the heat-adhesive component occupies all or part of the fiber surface (preferably 40% or more, particularly 60% or more of the fiber surface area), the core sheath type The eccentric core sheath type, the side by side type, the island-in-the-sea type, and the split-shape type may be taken in any one composite form. Especially, a core sheath type, an eccentric core sheath type, and a side by side type are more preferable.

Next, the heat-adhesive composite short fiber of this invention needs to be 3-40 pieces / 25 mm of crimp numbers, and 3 to 40% of a crimp rate. If the number of crimps is less than 3/25 mm, or the crimp rate is less than 3%, the entanglement between the short fibers is insufficient and the curd permeability deteriorates, which is not preferable because a high quality fiber structure cannot be obtained. On the other hand, when the number of crimps exceeds 40/25 mm or the crimp rate exceeds 40%, the entanglement between the short fibers becomes excessively large, so that sufficient carding cannot be achieved in the curd, and a high quality fiber structure cannot be obtained. I can't. As a more preferable range of crimp, the crimp number is in the range of 5 to 30 pieces / 25 mm, and the crimp rate is in the range of 5 to 30%. The crimp may be a mechanical crimp or a three-dimensional crimp, and may be appropriately selected and set in accordance with the intended use or purpose.

And fiber length and single yarn fineness do not need to specifically limit, What is necessary is just to set suitably according to a use and a purpose.

In the heat-adhesive composite short fibers of the present invention, in addition to the above requirements, it is important that the web area shrinkage defined below is 20% or less. Thereby, the composite fiber can be blended with 100% or other fibers to obtain a fiber structure excellent in dimensional stability even in a high temperature atmosphere. When this shrinkage rate exceeds 20%, the fiber structure excellent in dimensional stability in a high temperature atmosphere cannot be obtained. More preferred web area shrinkage is 10% or less.

<Web area shrinkage>

A curd web nonwoven fabric consisting of 100% of heat-sealable short fibers and having an area of A ₀ and a weight of 30 g / m 2 per unit area was left to stand for 2 minutes during hot air drying at 150 ° C., and the area A ₁ of the subsequent nonwoven fabric was measured. To obtain the following formula.

Web area shrinkage (%) = (A ₀ -A ₁ ) / A ₀ × 100

The polyester-based heat-adhesive composite short fibers of the present invention described above can be produced efficiently by, for example, the following method. That is, the above-mentioned amorphous polyester and polyalkylene terephthalate are compounded, preferably a core sheath, an eccentric core sheath, or a side by side type, which are melt-discharged, and the discharge thread is discharged at a speed of 1500 m / min or less. It is taken out to give an unoriented composite fiber. Then, the polyether polyester block copolymer was added 0.03% by weight or more to the weight of the fiber, and then 0.72 to 1.25 times the maximum draw ratio upon cooling at a temperature of T ₁ to (T ₂ + 30 ° C). It extends | stretches, and can further manufacture by crimping | crimping so that crimp number may be 3-40 pieces / 25 mm, and a crimp rate may be 3-40%, and it cuts to a desired length. Where T ₁ is the amorphous polyester and the glass transition point of the polyalkylene terephthalate, the glass transition temperature of any one of high-side of the, T ₂ refers to the glass transition point of the amorphous polyester.

In the case where the take-off speed exceeds 1500 m / min, even if the unstretched composite fiber obtained is stretched under the above conditions, the web surface shrinkage cannot be made 20% or less, which is not preferable.

The 1st point in the said manufacturing method is to give a polyether polyester block copolymer to the surface of this composite fiber in the step before extending | stretching the drawn unstretched composite fiber. By doing this, the non-crystalline glass transition point of the polyester; if also stretched at temperatures higher than (T ₂ that is, non-crystalline copolymer corresponding to the softening point of the polyester), the stretching temperature T a temperature not higher than the ₂ + 30 ℃ in the drawing process It is possible to obtain a polyester-based heat-adhesive composite short fiber having a web surface shrinkage of 20% or less without causing interfiber interlocking. Moreover, even if the said polyether polyester block copolymer adheres to the surface of a composite fiber, heat adhesiveness does not fall so much, and the fiber structure excellent in mechanical property can be obtained.

Simultaneous achievement of the anti-adhesion effect and the heat-adhesive retention effect is achieved by anionic surfactants or polyoxyalkylene adducts thereof, cationic surfactants, nonionic surfactants, mineral oils and the like which are commonly used as oils for producing short fibers. It cannot be used, nor can it be used as a polysiloxane treatment agent.

As the polyether polyester block copolymer to be preferably used, in particular, the dicarboxylic acid component is composed of a terephthalic acid component, an isophthalic acid component and / or an alkali metal salt sulfoisophthalic acid component, and the molar ratio thereof is 40:60 to 100: 0. And copolymerization of 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. Particularly, the effect of preventing the occurrence of deadlock in the aqueous emulsion stability and the stretching process is mentioned. It is preferable at the point of view. However, acid components such as adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-propanediol, 1,4-butanediol, 1,5 A small amount of diol components such as -pentanediol, 1,6-hexanediol, diethylene glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol may be copolymerized, and polyalkyl is used to adjust the molecular weight. One end group of len glycol may be blocked by ether bonds, such as monomethyl ether, monoethyl ether, and monophenyl ether. And as polyalkylene glycol, polyethyleneglycol, an ethylene oxide propylene oxide copolymer, polypropylene glycol, polytetramethylene glycol etc. are mentioned, for example, polyethyleneglycol is especially preferable.

Since the number average molecular weight of a polyether polyester block copolymer can obtain the higher anti-adhesion effect of the range of 3000-20000, it is preferable.

The amount of adhesion of the polyether polyester block copolymer to the unstretched fiber needs to be 0.03 wt% or more with respect to the unstretched fiber, and if it is less than 0.03 wt%, sufficient anti-sticking effect is not obtained at the time of stretching described later. Not desirable On the other hand, even if the adhesion amount is increased, the anti-deadlock effect reaches the limit and does not increase, so it is appropriate to be 0.5% by weight or less. Especially the range of 0.05 to 0.3 weight% is suitable.

The method for attaching the polyether polyester block copolymer to the surface of the unstretched composite fiber is not particularly limited, and can be given by any conventionally known method, but is usually given as an aqueous emulsion solution. At this time, in addition to the emulsifier for stabilizing this emulsion solution, it may contain additives such as an antistatic agent, a leveling agent, a rust inhibitor, an antifungal agent, and an antibacterial agent.

Next, the 2nd point in the said manufacturing method is extending | stretching temperature. The stretching temperature is, of course, set to T ₂ (glass transition point of amorphous polyester) or higher, but at the same time, the temperature above the glass transition point of polyalkylene terephthalate in order to heat-set the polyalkylene terephthalate which is a fiber forming component. You need to set it to. Even if the said polyether polyester block copolymer is previously given to the unstretched composite fiber surface, when extending | stretching temperature is less than either of the glass transition point of an amorphous copolyester and a polyalkylene terephthalate, this invention aims at The heat-adhesive composite short fibers excellent in dimensional stability can not be obtained. And it is also important not to the stretching temperature to a high temperature exceeding T ₂ (the glass transition point of the amorphous polyester) + 30 ℃. If the stretching temperature exceeds T ₂ + 30 ° C., it is not preferable because the interlocking of the amorphous polyester cannot be sufficiently prevented and the fusion fiber bundle is generated or the crimp stability when imparting crimp by the indentation crimp is deteriorated. Can not do it.

When extending | stretching temperature exists in the said temperature range, although the said extending | stretching may be single stage extending | stretching or multistage stretching of 2 or more stages, it is necessary to make total draw ratio 0.72-1.25 times the cold draw ratio. When the draw ratio is less than 0.72 times the cold draw ratio, the dimensional stability of the fiber structure is lowered. On the other hand, when the draw ratio is more than 1.25 times the draw ratio, the drawability is not only deteriorated but also the thermal adhesiveness is not preferable. Can not do it. In addition, the cold drawing ratio of the unstretched fiber referred to herein means that the unstretched composite fiber collected within 5 minutes immediately after spinning is stretched at a speed of 5 cm / sec with a chuck length of 10 cm in air at 25 ° C. and 65% relative humidity. It is obtained by dividing the chuck length spacing (cm) by the point which no longer extends by the initial chuck length (10 cm).

In the present invention, the stretching is performed by T ₁ (the temperature of either the glass transition point of the amorphous copolyester and the glass transition point of the polyalkylene terephthalate) ~ (T ₁ + 10 ℃) After the non-stretched composite fiber Cold new scale 0.7 ~ 1.0-fold stretching in at a temperature _{of, (T 1 + 10 ℃)} ~ (T 2 ( the glass transition of the amorphous copolymerizable polyester advantage) Stretching at 1.03 to 1.25 times at a temperature of + 30 ° C) is more effective in terms of improving dimensional stability and is more effective in preventing deadlocks.

And it is especially effective to use hot water as an extended heating medium.

The stretched composite fiber is cut to a desired length after crimping is applied under conditions in which the number of crimps is 3-40 pieces / 25 mm and the crimp rate is 3-40% according to a conventionally known method. In other words, when the crimped form is a mechanical crimp, the press-fit pressure and temperature conditions may be appropriately controlled using, for example, a press-fit crimp. On the other hand, in the case of three-dimensional crimping, the composite structure of the composite fiber may be selected or the cooling conditions during spinning may be appropriately selected.

The polyester-based heat-adhesive composite short fibers of the present invention thus obtained have good dimensional stability and are suitable for use in fiber structures such as nonwoven fabrics and mirror surfaces. The heat-adhesive composite short fibers may be used alone as a fiber structure such as a nonwoven fabric, or may be mixed with the heat-adhesive composite fiber as another main fiber to form a fiber structure such as a nonwoven fabric.

Hereinafter, an Example is given and this invention is demonstrated further more concretely. And each evaluation item in the Example followed the following method.

(a) Glass transition point (Tg), melting point (Tm)

It measured at the temperature increase rate of 20 degree-C / min using the differential scanning calorimeter DSC-7 type | mold by the Perkin Elmer company.

(b) intrinsic viscosity ([η])

It measured at 35 degreeC with orthochlorophenol as a solvent.

(c) crimp number, crimp rate

It measured according to the method described in JIS L 1015 7.12.

(d) fine island

It measured according to the method described in JIS L 1015 7.5.1 A method.

(e) fiber length

It measured according to the method described in JIS L 1015 7.4.1 C method.

(f) emulsion adhesion rate

The weight of the residue extracted for 10 minutes at a bath ratio of 1:20 with 30 ° C methanol from the fiber was measured and the value divided by the predetermined fiber weight was used.

(g) web area shrinkage and deformation of the fiber structure

Hot air dryer (Sadake Chemical Machinery) which formed a curd web composed of 100% of heat-adhesive composite short fibers having a weight of 30 g / m 2 and an area A ₀ (25 cm × 25 cm = 625 cm 2) per unit area, and maintained at 150 ° C. industries, producing hot air circulating constant-temperature drier: allowed to stand 2 minutes in a 41-S4), and the area shrinkage percentage was determined by the following formula from the area a ₁ of the web after the heat treatment the curd. And it was set as the thing whose area shrinkage rate is 20% or less.

Area shrinkage (%) = (625-A ₁ ) / 625 × 100

(h) deadlock

The case where the deadlock occurred at the time of extending | stretching and the deadlock was confirmed in the incapacity or the curd web was made into defect, and the other was made favorable.

Example 1

Polyethylene terephthalate having an intrinsic viscosity of 0.64, Tg 67 ° C, and Tm 256 ° C as a fiber-forming component, and an acid component as a molar ratio as an acid component as a heat-adhesive component: terephthalic acid component: isophthalic acid component = 60: 40, and a diol component in a molar ratio of ethylene glycol: Each pellet was dried under reduced pressure using amorphous copolymer polyester having an intrinsic viscosity of 0.56 and Tg 64 ° C., copolymerized at a ratio of diethylene glycol = 95: 5, and then supplied to a core sheath type composite melt spinning apparatus, Melt-release was carried out from the spinneret having a spin hole number of 450 at a complex ratio of volume ratio 50/50, spinning temperature of 290 ° C., and discharge amount of 650 g / min. The release sand was cooled by cold air at 30 ° C., and the acid component was copolymerized with 70% by weight of polyethylene glycol having a terephthalic acid component: isophthalic acid component = 80/20 and a glycol component of ethylene glycol and a number average molecular weight of 3000. A treatment agent consisting of an emulsion of a polyether polyester block copolymer having an average molecular weight of 10000 was given using an oiling roller so that the net amount of adhesion to the fiber weight was 0.1% by weight, and the phosphorus at 900 m / min. To obtain an unstretched core sheath composite fiber. And the maximum draw ratio (hereinafter referred to as CDR) at the time of cooling this unstretched fiber was 4.5 times.

The unstretched composite fiber was concentrated, stretched to 3.5 times (0.78 times CDR) in hot water at 72 ° C. with 110,000 dtex (100,000 denier) tow, and then stretched to 1.15 times in hot water at 80 ° C. (4.0 times the total draw ratio: 0.89 times the CDR), after impregnating a spinning emulsion consisting of lauryl phosphate potassium salt, crimped with a press-fit crimp that was naturally cooled to 35 ° C, and cut into a fiber length of 51 mm. The heat-adhesive composite short fiber of 4.4 dtex of single yarn fineness, 10 crimp numbers / 25 mm, and a crimp rate of 15% was obtained.

[Examples 2 to 10 and Comparative Examples 1 to 6]

Except for changing the heat-adhesive component, the fiber-forming component, the treatment agent, the draw ratio, and the draw temperature, under the same conditions as in Example 1, single yarn fineness 4.4 dtex, fiber length 51 mm, number of crimps 10/25 mm, crimp A heat-adhesive composite short fiber having a rate of 15% was obtained.

Table 1 shows the fiber configuration of these examples and comparative examples, Table 2 shows the treatment agent types, Table 3 shows the spinning and stretching conditions, and Table 4 shows the results of the fiber evaluation.

Compound level F1 F2 F3 F4 F5 F6 Thermal Adhesive Ingredients Acid TA 60 60 55 70 75 60 IA 40 40 40 30 25 40 SA - - 5 - - - Glycol Ingredients EG 95 100 100 62 44 95 DEG 5 - - 8 6 5 HMG - - - 30 50 - Tg ℃ 64 69 59 55 40 64 Tm ℃ - - - - - - [η] 0.56 0.57 0.55 0.56 0.56 0.56 Fiber Forming Ingredients Kinds PET PET PET PET PET PBT Tg ℃ 67 67 67 67 67 25 Tm ℃ 256 256 256 256 256 228 [η] 0.64 0.64 0.64 0.64 0.64 0.87  TA: terephthalic acid IA: isophthalic acid SA: sebacic acid EG: ethylene glycol DEG: diethylene glycol HMG: hexamethylene glycol PET: polyethylene terephthalate PBT: polybutylene terephthalate

 Processor level O1 O2 O3 O4 O5 Polyether Polyester Block Copolymer Component - - Acid TA 80 90 72 IA 20 10 18 SIA - - 10 Glycol Ingredients EG 100 100 100 Polyalkylene glycol Kinds PEG3000 M-PEG3000 PEG4000 Copolymerization% 70 80 70 Number average molecular weight 10000 9000 11000 Other ingredients - - - Phosphate 1 Phosphate 2  TA: terephthalic acid IA: isophthalic acid SIA: 5-sodium sulfoisophthalic acid PEG3000: polyethylene glycol with an average molecular weight of 3000 PEG4000: polyethylene glycol with an average molecular weight of 4000 M-PEG3000: polyethylene glycol monophenyl ether phosphate with an average molecular weight of 3000 1: lauryl Phosphate Potassium Salt Phosphate 2: Partial Phosphate Potassium Phosphate Salt of Lauryl Alcohol with an average number of 5 moles of ethylene oxide

radiation Stretch Compound level Treatment level CDR First stage 2nd stage Total draw ratio Temperature Magnification / CDR Temperature Magnification / CDR Magnification (CDR) Example 1 F1 O1 4.5 72 0.78 72 1.15 4.00 (0.89) Comparative Example 1 F1 O1 4.5 65 0.78 60 1.15 4.00 (0.89) Comparative Example 2 F1 O4 4.5 65 0.78 60 1.15 4.00 (0.89) Comparative Example 3 F1 O4 4.5 72 0.78 72 1.15 4.00 (0.89) Comparative Example 4 F1 O5 4.5 72 0.78 72 1.15 4.00 (0.89) Example 2 F1 O1 4.5 72 0.78 80 1.15 4.00 (0.89) Example 3 F1 O1 4.5 72 0.78 85 1.15 4.00 (0.89) Example 4 F1 O1 4.5 72 0.96 80 1.05 4.54 (1.01) Comparative Example 5 F1 O1 4.5 72 0.60 72 1.15 3.10 (0.69) Example 5 F1 O2 4.5 72 0.78 72 1.15 4.00 (0.89) Example 6 F1 O3 4.5 72 0.78 72 1.15 4.00 (0.89) Example 7 F2 O1 4.5 72 0.78 72 1.15 4.00 (0.89) Example 8 F3 O1 4.5 72 0.78 72 1.15 4.00 (0.89) Example 9 F4 O1 4.5 72 0.78 72 1.15 4.00 (0.89) Comparative Example 6 F5 O1 4.5 72 0.78 72 1.15 4.00 (0.89) Example 10 F6 O1 3.8 72 0.78 72 1.15 3.38 (0.89)

Fiber evaluation Deadlock Web area shrinkage (%) Web quality after shrinkage Example 1 Good 18.5 Good Comparative Example 1 Good 73.9 Bad Comparative Example 2 Good 55.3 Bad Comparative Example 3 Bad Inability to stretch - Comparative Example 4 Bad Inability to stretch - Example 2 Good 8.1 Good Example 3 Good 5.1 Good Example 4 Good 6.8 Good Comparative Example 5 Bad Inability to stretch - Example 5 Good 17.5 Good Example 6 Good 18.1 Good Example 7 Good 18.3 Good Example 8 Good 16.3 Good Example 9 Good 16.1 Good Comparative Example 6 Bad Inability to stretch - Example 10 Good 14.8 Good

Although the polyester-based heat-adhesive composite short fibers of the present invention can be formed into a fiber structure at a relatively low temperature, it is possible to provide a high-quality fiber structure having good dimensional stability and hardly being deformed even when used in a high temperature atmosphere. have. In addition, according to the production method of the present invention, it is possible to produce the heat-adhesive composite short fibers very stably and easily without causing the deadlock.

Claims (8)

As heat-adhesive composite short fibers having a non-crystalline polyester having a glass transition point of 50 to 100 ° C and no crystal 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. The polyester type heat-adhesive composite short fiber characterized by the crimp number being 3-40 pieces / 25mm, the crimp rate being 3-40%, and the web area shrinkage rate defined below. <Web area shrinkage> A curd web nonwoven fabric consisting of 100% of heat-adhesive composite short fibers and having an area of A ₀ and a weight of 30 g / m 2 per unit area was left to stand in a hot air dryer maintained at 150 ° C. for 2 minutes, and then the area A ₁ of the nonwoven fabric thereafter. Measured and obtained by the following formula. Web area shrinkage (%) = (A ₀ -A ₁ ) / A ₀ × 100 The polyester-based heat-adhesive composite short fiber according to claim 1, wherein 0.03 to 0.5% by weight of a polyether polyester block copolymer is attached to the fiber surface with respect to the fiber weight. The polyester-based heat adhesive according to claim 1 or 2, wherein the heat adhesive component is an amorphous copolyester composed of an isophthalic acid component, terephthalic acid component, ethylene glycol component, and diethylene glycol component. Composite short fibers. The polyester type heat-adhesive composite short fiber according to claim 1 or 2, wherein the fiber-forming component is polyethylene terephthalate. After melting and compounding the amorphous polyester having a glass transition point of 50 to 100 ° C. and no melting point and a polyalkylene terephthalate having a melting point of 220 ° C. or higher, the composite discharge yarn was cooled and solidified, and then the speed was 1500 m / min. Taken below, it is taken as an unstretched composite fiber, and then, after imparting 0.03 to 0.5% by weight of the polyether polyester block copolymer to the fiber weight, the temperature of T ₁ to (T ₂ + 30 ° C.) is given. At the time of cooling at 0.72 to 1.25 times the maximum draw ratio, and further crimped to give a crimp so that the crimp number is 3-40 pieces / 25mm, and the crimp rate is 3-40%. Method of making fibers. Herein, T ₁ is the temperature of either the glass transition point of the amorphous polyester or the glass transition point of the polyalkylene terephthalate, and T ₂ is the glass transition point of the amorphous polyester. The stretching according to claim 5, wherein the stretching is performed at a temperature of T ₁ to (T ₁ + 10 ° C) at a temperature of 0.70 to 1.00 times the maximum draw ratio at the time of cooling, and further, (T ₁ + 10 ° C) to (T ₂ + 30 ° C. The manufacturing method of the polyester type heat-adhesive composite short fiber which is the two stage extending | stretching extended | stretched 1.03 to 1.25 times at the temperature of (). The manufacturing method of the polyester type heat-adhesive composite short fiber of Claim 5 or 6 whose heating medium used for extending | stretching is hot water. The polyether polyester block copolymer according to claim 5 or 6, wherein the acid component is a terephthalic acid component, an isophthalic acid component, an alkali metal salt sulfoisophthalic acid component, or an isophthalic acid component and an alkali metal salt sulfoisophthalic acid component. Polyester-based thermal adhesiveness obtained by copolymerizing 20 to 95% by weight of a polyalkylene glycol having a molar ratio of 40:60 to 100: 0, a glycol component of ethylene glycol, and a number average molecular weight of 600 to 10000. Method for producing composite short fibers.