JP2003027339A - Polyester-based conjugate fiber and fiber structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conjugate fiber for fiber structures comprising a polyester-based conjugate short fiber to which latent crimpability is imparted, scarcely causing loss of bulkiness due to heat, excellent in bulkiness and usable for padding of bedding, sofa, cushion and automobile interior material. SOLUTION: This polyester-based conjugate fiber is obtained by conjugating copolyesters which are mutually different in viscosity in eccentric form or side by side form. In the polyester-based conjugate fiber, the difference of intrinsic viscosity of these copolyesters is 0.05-0.15 and these copolyesters are polyalkylene terephthalate-based copolyesters in which 8-30 mol% 2,6-naphthalene dicarboxylic acid component is copolymerized and have >=80 deg.C glass transition point. This fiber structure comprises the conjugate fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be used as an automobile seat cushion material, ceiling material, floor material, sound absorbing material or trunk room interior material, and is bulky for a long period of time and with little sagging even in a high temperature atmosphere. The present invention relates to a composite fiber and a fiber structure having excellent properties.

[0002]

2. Description of the Related Art Conventionally, polyurethane foam has been mainly used as a cushioning material for furniture, such as backrests and cushions of sofas and chairs, beds, automobile seats and the like. However, it has been pointed out that polyurethane foam has a problem of gas generation during incineration, a problem of CFC gas during production, and a problem of recyclability.
As a method for solving the problem, as a substitute material for polyurethane foam, solid cotton obtained by mixing polyester short fibers and heat-adhesive fibers has been proposed and often used.

For example, JP-A-58-31150,
JP-A-2-154050, JP-A-3-22035
There are methods proposed in Japanese Patent Laid-Open No. 4 and Japanese Patent Laid-Open No. 3-249213. Then, in these methods, polyethylene terephthalate fibers and binder fibers made of an amorphous polymer are used as fibers constituting the fiber structure.

However, when such a fibrous structure is used as a vehicle seat, it is in a high temperature atmosphere (in an atmosphere of about 70 ° C.) in a vehicle on a summer day or a sunny day, and therefore polyethylene, which is a main fiber, is used. The terephthalate fiber and the binder fiber are thermally deformed and sag (so-called thermal sag occurs), resulting in poor cushioning properties.

On the other hand, as a method for improving the thermal fatigue of the heat-adhesive fiber, Japanese Patent Application Laid-Open No. 4-240219 proposes a solid cotton using elastic heat-adhesive fiber. However, even with cotton using elastic heat-bondable fibers, the main fiber is polyethylene terephthalate fiber, so 70
In a ℃ atmosphere, it is susceptible to thermal deformation, causing the cushion to experience heat settling. In addition, the proposed elastic heat-adhesive fiber is subjected to composite spinning at a high spinning temperature in the manufacturing method, so that the low-melting point polyester elastomer, which is a heat-adhesive component, is significantly deteriorated by heat, resulting in a low molecular weight and recovery of the elastomer. There is a problem that the sex is lowered.

A technique using polyethylene naphthalate fiber has been proposed in Japanese Patent Laid-Open No. 165884/1994 for the purpose of improving the heat resistance of the main fiber. The cushion using polyethylene naphthalate fiber as the main fiber has a good heat-resistant settling property in an atmosphere of 70 ° C, but has a low heat-resistant crimp ratio (that is, the heat of the heat-bonding treatment causes the crimp of the main fiber to be crimped). However, the crimping rate decreases, and since the cushion is made of cotton with webs laminated, the compressive stress is low at 25%, and the volume decreases when it is repeatedly used, and it becomes paper-like, which is not preferable. Further, polyethylene naphthalate fibers have problems in that they are economically unfavorable due to poor operability during production and high price.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a polyester-based conjugate fiber and a fiber structure having a low bulkiness in a 70 ° C. atmosphere and excellent bulkiness. It is what

[0008]

Means for Solving the Problems The present inventors have arrived at the present invention as a result of extensive studies to develop such a novel fiber structure.

That is, the present invention is a conjugate fiber in which copolyesters having different viscosities are joined in an eccentric type or a side-by-side type, and the intrinsic viscosity difference of the copolyester is 0.05 to 0.15. And the copolymerized polyester is a polyalkylene terephthalate-based copolymerized polyester obtained by copolymerizing a 2,6-naphthalenedicarboxylic acid component in the range of 8 mol% to 30 mol%,
The gist is a polyester-based composite fiber having a glass transition point of 80 ° C. or higher.

In the present invention, the polyester-based conjugate fiber is contained in an amount of 80 to 50% by mass and a crystalline binder component having a melting point lower than that of the polyester-based conjugate fiber by 40 ° C. or more on at least a part of the surface of the fiber. The binder fiber is composed of 20 to 50% by weight, the polyester-based composite fiber has a three-dimensional crimp, and the constituent fibers are
A gist of the fiber structure is characterized in that the crystalline binder component is melted or softened to be adhered.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The conjugate fiber of the present invention is a conjugate fiber in which copolyesters having different viscosities are joined in an eccentric type or a side-by-side type.

In the present invention, the copolyester constituting the conjugate fiber is a polyalkylene terephthalate-based copolyester obtained by copolymerizing 2,6-naphthalenedicarboxylic acid as an acid component in the range of 8 to 30 mol%.
It is abbreviated as copolymerized polyester A. ).

By using the copolyester A as the polymer constituting the conjugate fiber, the copolyester A is used at 70 ° C.
It is possible to obtain a composite fiber that is free from heat settling in an atmosphere and can maintain bulkiness even in a high temperature atmosphere. Further, it is possible to obtain a bulky composite fiber having a large number of crimps and a large number of crimps, rather than fine crimps.

In the copolyester A, 2,6-
The copolymerization amount of the naphthalenedicarboxylic acid component (hereinafter abbreviated as NDCM) is 8 to 30 mol%, preferably 10 to 20 mol%.

When the copolymerization amount of NDCM is less than 8 mol%,
The glass transition point (hereinafter abbreviated as Tg) is less than 80 ° C., the molecular structure becomes unstable due to micro Brownian motion of an amorphous portion in an atmosphere of 70 ° C., and the molecular structure is easily deformed when a load is applied. The target composite fiber cannot be obtained. A fiber structure composed of such composite fibers,
It is not preferable because it is easily deformed by heat.

On the other hand, when the copolymerization amount of NDCM exceeds 30 mol%, the polymer becomes amorphous and the operability at the time of production is lowered, and the strength of the obtained conjugate fiber is lowered, which is not preferable. .

T of the copolyester A in the present invention
g needs to be 80 ° C. or higher. When the Tg is less than 80 ° C., for the same reason as in the case where the copolymerization amount of NDCM is less than 8 mol%, the composite fiber is easily deformed when subjected to a load in an atmosphere of 70 ° C. The resulting fibrous structure is also not preferable because it is easily thermally deformed. The higher the Tg, the better the sag resistance in an atmosphere of 70 ° C, but in consideration of the operability and cost during manufacturing,
Tg is preferably 80 to 90 ° C.

The copolymerized polyesters A constituting the conjugate fiber of the present invention have mutually different viscosities, and the difference in their intrinsic viscosities (hereinafter abbreviated as [η]) is 0.05 to.
It is 0.15. If the [η] difference is less than 0.05, sufficient three-dimensional crimps cannot be expressed in the relaxation heat treatment, and the fiber structure made of such composite fibers is unfavorable because the bulkiness decreases. On the other hand, if the [η] difference exceeds 0.15, the yarn bending angle just below the nozzle becomes large, and the operability deteriorates, which is not preferable.

The main component constituting the copolyester A is alkylene terephthalate. The alkylene terephthalate preferably has a melting point (hereinafter abbreviated as Tm) of 220 ° C. or higher, and for example,
Examples thereof include ethylene terephthalate and butylene terephthalate. Among them, ethylene terephthalate is preferably used from the viewpoint of productivity, mechanical properties and the like. Further, ethylene terephthalate contains a small amount of a copolymerization component, a matting agent, a pigment,
You may contain additives, such as a lubricant.

The cross-sectional shape of the conjugate fiber of the present invention is not limited to a circular shape, but may be a flat type, a trilobal type, a hexalobal type, or a W type.
It may be a modified cross section such as a mold or an H shape, or a hollow cross section having a hollow portion. In the case of a hollow cross section, in order to improve the bulkiness and sag resistance of the fiber structure made of the composite fiber, it is preferable that the hollow cross section has a hollow ratio of 10 to 30%.

The composite fiber of the present invention develops a three-dimensional crimp by heat treatment in a relaxed state. The three-dimensional crimp is a coil-shaped spiral crimp. In the present invention, the composite fiber is 5 to 20 by dry heat treatment at 170 ° C.
It is preferable to develop a three-dimensional crimp of 25 mm
More preferably, it is 7 to 15 pieces / 25 mm. When the number of three-dimensional crimps developed by the heat treatment is less than 5/25 mm, the fiber becomes bulky, but a large coil-shaped spiral crimp, that is, the diameter of the spiral crimp is large (internal space). Therefore, it is easy to get tired when a force is applied. On the other hand, 20
When the number exceeds 25 mm, the spiral crimp becomes a small coil shape, and the bulkiness of the fiber tends to be poor.

The conjugate fiber of the present invention can be obtained by the following method. That is, two kinds of copolyester A having different viscosities are melted by using a commonly used two-component type composite spinning device, and a side-by-side type or eccentric core-sheath type spinneret is used. Melt spinning. The spun yarn is cooled by blowing air using a conventionally known cooling device such as a horizontal blowing device or an annular blowing device, and then an oil agent is applied to the spun yarn and the wound yarn is taken up by a take-up roller. Considering the spinnability, the speed of the take-up roller is 5
It is preferably from 00 m / min to 2000 m / min.

A plurality of the obtained undrawn yarns are drawn and aligned, and drawn and heat-treated by a conventionally known drawing machine between roller groups having different peripheral speeds. Then, a relaxation heat treatment is performed to develop a three-dimensional crimp, and then the fiber is cut into a desired fiber length to obtain the conjugate fiber of the present invention.

Next, the fiber structure of the present invention will be described. The fibrous structure of the present invention comprises the above-mentioned composite fiber and binder fiber, and the constituent fibers are bonded to each other by melting or softening the binder component of the binder fiber.

As the binder fiber, a polyester-based binder fiber having a crystalline binder component having a melting point of 40 ° C. or more lower than the melting point of the copolyester A constituting the composite fiber is used on at least a part of the surface of the fiber.

When the difference between the melting point of the copolyester A and the melting point of the crystalline binder component is less than 40 ° C., the copolyester A is likely to be thermally decomposed by the heat treatment for forming the fiber structure, and the fiber structure is obtained. It is not preferable because the mechanical performance and the like of the above deteriorate.

The form of the polyester binder fiber is a single-phase form composed of the binder component alone, and the binder component is arranged in the sheath portion, and the binder component has a melting point (softening point if there is no melting point). 40
A core-sheath type composite form in which a polyester polymer having a temperature of ℃ or higher is arranged in the core portion, and a polyester system having a temperature of 40 ℃ or higher higher than the melting point (softening point for a material having no melting point) of the binder component. Examples thereof include a side-by-side composite form in which the polymer and the polymer are arranged in parallel, and the core-sheath composite form described above can be preferably used in the present invention.

Examples of such a core-sheath type composite binder fiber include a core-sheath composite fiber in which polyethylene terephthalate is arranged as a core portion and a low melting point crystalline copolyester is arranged as a sheath portion.

As the crystalline binder component used in the present invention, those having crystallinity and having ethylene terephthalate as a main repeating unit are preferable, and particularly, a terephthalic acid component, an aliphatic lactone component, an ethylene glycol component and 1, A substance composed of a 4-butanediol component can be preferably used.

The mixing ratio of the polyester-based conjugate fiber of the present invention and the binder fiber is as follows.
It is set to 0 to 50% by mass / binder fiber 20 to 50% by mass. When the blending ratio of the polyester-based composite fiber exceeds 80% by mass, the amount of the binder fiber for adhering the fibers to each other to maintain the shape is relatively small, and thus the shape retention of the obtained fiber assembly is poor, Molding processability is reduced,
It becomes easily deformed when compressed. On the other hand, when the blending ratio of the polyester-based composite fiber is less than 50% by mass,
Since the ratio of the binder fibers becomes too large, the obtained fiber structure becomes hard, and the bulkiness and the compressive residual strain at the time of heating at 70 ° C. increase, which is not preferable.

Next, a preferred method for producing the fiber structure of the present invention will be described. The composite fiber of the present invention in which the three-dimensional crimp is developed and the polyester-based binder fiber are mixed, and a web is formed by a card machine or the like. As the blending ratio, composite fiber / polyester binder fiber = 8
0 to 50/20 to 50 (mass%), and more preferably composite fiber / polyester binder fiber = 80 to
70/20 to 30 (mass%).

The obtained web is heat-treated by passing through a heat treatment apparatus to melt or soften the binder component, and the constituent fibers are bonded and integrated at their intersections to obtain a fibrous structure. As the heat treatment apparatus, a hot air circulating dryer, a hot air once-through dryer, a suction drum dryer, a Yankee drum dryer, or the like is used.

The obtained fibrous structure can be molded according to the application. That is, the obtained fibrous structure is preheated and hot-pressed or cold-pressed into a predetermined shape to be molded. As the molding form, a form suitable for a desired application may be used.

[0035]

EXAMPLES Next, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these. The evaluation methods for various physical properties described in the examples are as follows.

(1) Tg (° C.), Tm (° C.) A differential scanning calorimeter DSC-7 type manufactured by Perkin Elmer Co. was used and measured at a temperature rising rate of 20 ° C./min.

(2) Intrinsic viscosity ([η]) Using an equal weight mixture of phenol and ethane tetrachloride as a solvent,
It was measured at a temperature of 20 ° C.

(3) Compressive Residual Strain Rate (%) (Heat-resistant Settling Property) As a test piece, a 10 cm × 10 cm square fiber structure was prepared, and the method of JISK-6401-5-5 (70
(° C × 22 hours). A 70 ° C. compressive residual strain rate of 25% or less was defined as good heat resistance.

(4) 25% compressive stress (N) (bulkness) JIS K-6401-5-6 Measurement of hardness According to the method described in Method A, the compressive force at 25% compression with respect to the initial bulk. Was measured. A 25% compressive stress of 150 N or more was considered as good bulkiness.

(5) Evaluation of operability ◯: There is no problem in spinning and drawing. X: The yarn was frequently broken during spinning, and the yarn was frequently wound around the roller, which was regarded as poor operability.

(6) Evaluation of texture of fiber structure ◯: The bulkiness and repulsion of the fiber structure are good. X: The fiber structure becomes paper-like and hard.

Example 1 As the copolyester A, one component was an ethylene terephthalate type copolyester (extremely polymerized by a conventional method, which was obtained by copolymerizing 15 mol% of 2,6-naphthalenedicarboxylic acid as an acid component). Viscosity 0.65, Tg8
4 ° C., Tm 240 ° C .; hereinafter, copolyester (X)
Is abbreviated. ) Was used. The other component is an ethylene terephthalate-based copolyester obtained by copolymerizing 15 mol% of 2,6-naphthalenedicarboxylic acid as an acid component polymerized by a conventional method (intrinsic viscosity 0.57, T
g 84 ° C., Tm 240 ° C .; hereinafter abbreviated as copolyester (Y). ) Was used.

The above-mentioned two kinds of copolyesters were spun at a spinning temperature of 280 ° C. and a composite ratio (X / Y) = 5 in a side-by-side type hollow round section spinner using a composite melt spinning apparatus.
0/50, winding speed 1100 m / min, discharge amount 350 g /
Melt spun in minutes. The unstretched yarn obtained by melt spinning was bundled into a bundle of 11 Ktex, stretched at a stretching temperature of 80 ° C. and a stretching ratio of 4.5, and heat-treated at a relaxation heat treatment temperature of 170 ° C. × 5 minutes. After tow cooling, apply oil to finish and cut into 51 mm length, single yarn fineness 6.6 dte
x, number of three-dimensional crimps 8.0 / 25 mm, crimp rate 20%,
A polyester-based composite fiber having a hollow ratio of 15% was obtained.

Next, as a binder fiber, Tm was added to the core.
256 ° C polyethylene terephthalate, Tg3 on sheath
A crystalline copolyester having a temperature of 2 ° C. and a Tm of 160 ° C. is arranged and spun using a composite melt spinning device, and a core-sheath spinneret has a spinning temperature of 270 ° C. and a core-sheath ratio (core / sheath) = 50/5.
The melt spinning was performed at 0, a winding speed of 700 m / min, and a discharge rate of 642 g / min. The undrawn yarn obtained by melt spinning is 11 Kt
2. Bundled into a bundle of ex, stretching temperature 60 ° C., stretching ratio 3.
After stretching at 8 times, mechanical crimping was applied by a press type crimping machine. Apply a finishing oil to the crimped tow and cut it to a length of 51 mm to obtain a single yarn fineness of 4.4 dtex.
Binder fiber of was obtained.

The obtained polyester-based composite fiber (main fiber) and binder fiber were mixed at a mass ratio of 70:30 to prepare a web with a card machine, and then a plurality of webs were laminated to give a basis weight. A laminated web of 1500 g / m ² was obtained. After heat-bonding the laminated web at 180 ° C. for 20 minutes, the laminated web is regulated to have a thickness of 35 mm at 60 ° C.
A crystallization heat treatment was performed at 110 ° C. for 20 minutes to obtain a fiber structure.

Example 2 In the polyester-based conjugate fiber (main fiber), the polyester-based conjugate fiber and the polyester-based conjugate fiber were prepared in the same manner as in Example 1 except that the intrinsic viscosity of the copolyester (Y) was changed as shown in Table 1. A fibrous structure was obtained.

Example 3 The procedure of Example 1 was repeated except that the copolymerization amount, intrinsic viscosity, and Tg of the copolymerized polyester (X) of the polyester-based conjugate fiber (main fiber) were changed as shown in Table 1. A polyester composite fiber and a fiber structure were obtained.

Examples 4 and 5 Example 1 except that the mixing ratio of polyester-based composite fiber (main fiber) and binder fiber was changed as shown in Table 1.
A fiber structure was obtained in the same manner as in.

Comparative Examples 1 and 2 In the same manner as in Example 1 except that the intrinsic viscosity of the copolyester (Y) of the polyester conjugate fiber (main fiber) was changed as shown in Table 1, the polyester conjugate fiber was used. And a fibrous structure was obtained.

Comparative Example 3 Polyethylene terephthalate (intrinsic viscosity 0.61, Tm 256 ° C.) was used in place of the copolyester (X) of the polyester-based composite fiber (main fiber), and the copolyester (Y) copolymerization amount was used. A polyester-based conjugate fiber and a fiber structure were obtained in the same manner as in Example 1 except that the intrinsic viscosity and Tg were changed as shown in Table 1.

Comparative Examples 4 and 5 Copolymerization amount of polyester-based composite fiber (main fiber) The copolymerization amount of polyesters (X) and (Y), intrinsic viscosity and Tg are shown in Table 1.
Except that the change is made as shown in
A polyester composite fiber and a fiber structure were obtained.

Comparative Examples 6 and 7 Example 1 except that the mixing ratio of the polyester-based composite fiber (main fiber) and the binder fiber was changed as shown in Table 1.
A fiber structure was obtained in the same manner as in.

Comparative Example 8 Copolymerization amount of polyester-based composite fiber (main fiber) Polyesters (X) and (Y), intrinsic viscosity and Tg are shown in Table 1.
Except that the change is made as shown in
A polyester composite fiber and a fiber structure were obtained.

Table 1 shows the results of measurement of various physical properties of the polyester-based composite fibers (main fibers) and the fiber structures obtained in Examples 1 to 5 and Comparative Examples 1 to 8.

[0055]

[Table 1]

The fibrous structures using the polyester-based conjugate fibers (main fibers) obtained in Examples 1 to 5 have good operability and texture at the time of production, 25% compressive stress, 70 ° C.
The compressive residual strain rate in the atmosphere was excellent.

In Comparative Example 1, since the difference in intrinsic viscosity was small, sufficient crimp could not be expressed in the relaxation heat treatment, and the 25% compressive stress (bulkness) of the fiber structure was insufficient.

In Comparative Example 2, since the difference in intrinsic viscosity was large, the yarn bending angle immediately below the spinning nozzle was large, the operability was poor, and composite fibers could not be obtained.

In Comparative Example 3, since PET was used as one of the components constituting the composite short fiber (main fiber), the compressive residual strain rate of the fiber structure in the 70 ° C. atmosphere was insufficient.

Comparative Example 4 is an ND copolymerized with the copolymerized polyester constituting the composite short fiber (main fiber).
Since the amount of CM copolymer was small, Tg was 80 ° C. or less, and the compressive residual strain rate of the fiber structure in the 70 ° C. atmosphere was insufficient.

Comparative Example 5 is an ND copolymerized with the copolyester constituting the composite short fiber (main fiber).
Since the amount of CM copolymerization is large, the polymer becomes amorphous, adhesion occurs during spinning, yarn breakage easily occurs, and the operability during manufacturing is reduced.

In Comparative Example 6, when the fibrous structure was obtained, the mixing ratio of the binder fibers was small, so that the adhesiveness was poor and the fibers were separated from each other, and the 70 ° C. compression residual strain rate of the fibrous structure was large. It was easily deformed during compression. In addition, the moldability of the fiber structure was poor.

In Comparative Example 7, when the fiber structure was obtained, the blending ratio of the binder fibers was too large (the amount was more than 50% by mass), so that the texture of the fiber structure was hard and the temperature was 70 ° C.
The compression set was inferior.

In Comparative Example 8, in one of the copolyesters constituting the composite staple fiber (main fiber), the amount of the copolymerized NDCM was small, so that Tg was 80 ° C. or lower, and the fiber structure was 70 ° C. The compressive residual strain rate in the atmosphere was insufficient.

[0065]

Industrial Applicability The polyester-based conjugate fiber of the present invention is a copolyester having a specific viscosity difference between the two polymers constituting the conjugate fiber, and is ND.
Since a copolyester A having a Tg of 80 ° C. or higher, which is obtained by copolymerizing CM in a specific amount, is arranged in an eccentric type or a side-by-side type, it exhibits a coiled three-dimensional crimp and has excellent bulk performance. In addition, it is less likely to cause fatigue even in a high temperature atmosphere.

Furthermore, the polyester-based conjugate fiber and the polyester-based binder fiber having the crystalline binder component on at least a part of the surface of the fiber are mixed in a specific ratio, and the constituent fibers are mixed with each other in the crystalline binder component. Since the fibrous structure adhered by melting or softening uses a crystalline thermo-adhesive component in the thermo-adhesive fiber, it is particularly excellent in bulk performance and high temperature atmosphere when molded into cotton or the like. There is no heat settling in.

Such a fibrous structure of the present invention requires heat resistance (about 70 ° C.) for automobile seat cushions, automobile ceiling materials, floor materials, luggage compartments, automobile interior materials such as sound absorbing materials, etc. It can be preferably used in the cushion field.

Further, the conjugate fiber and the fiber structure of the present invention are not limited to the above-mentioned applications, but are also applicable to sofas and chair backs,
It can also be suitably used as a padding for furniture such as cushions and beds.

Continued front page    F-term (reference) 4L041 AA07 AA20 AA25 BA02 BA05                       BA09 BA22 BA42 BA49 BA59                       BA60 BD03 BD09 BD11 BD20                       CA06 CA10 DD04                 4L047 AA21 AA27 AB10 BA09 BB06                       CB02 CB03 CC09 CC10

Claims (2)

[Claims] 1. A co-polyester having different viscosities, which is an eccentric type or a side-by-side type conjugated fiber, wherein the co-polyester has an intrinsic viscosity difference of 0.05 to 0.15. Polymerized polyester contains 2,6-naphthalenedicarboxylic acid as an acid component of 8
Polyester terephthalate-based copolyester copolymerized in the range of 30 mol% to 30 mol% and having a glass transition point of 80 ° C. or higher. 2. A polyester binder having 80 to 50% by mass of the polyester conjugate fiber according to claim 1 and a crystalline binder component having a melting point lower than that of the polyester conjugate fiber by 40 ° C. or more on at least a part of the surface of the fiber. The polyester-based composite fiber has three-dimensional crimp, and the constituent fibers are adhered to each other by melting or softening the crystalline binder component. A fibrous structure.