JP2001207360A - Ball-like wadding and fiber structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ball-like wadding which comprises mechanically crimped polyester-based staple fibers and heat-adhesive fibers and is suitable as a cushion material for bedding, sofas, cold-proof clothing, automotive interiors or the like which are mainly produced by a blowing method. SOLUTION: This ball-like wadding having an average diameter of 3 to 25 mm and comprising 20 to 50 wt.% of crystalline polyester-based heat-adhesive fibers and 80 to 50 wt.% of polyester-based staple fibers, characterized in that the polyester-based staple fibers comprise a polyester having a glass transition point of >=80 deg.C, a crimp percent retention of >=85% before and after a thermal treatment at 210 deg.C, a single fiber fineness of 2 to 30 denier and a fiber length of 10 to 60 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball-shaped cotton in which polyester-based short fibers and heat-adhesive fibers are entangled with each other. More particularly, the present invention relates to a ball-shaped cotton and a fiber structure capable of obtaining a fiber structure suitable for a cushion material of an automobile interior material.

[0002]

2. Description of the Related Art Conventionally, furniture stuffing such as sofas and chair backrests, cushions and the like, beds and car seat cushioning materials, or car ceiling materials, flooring materials, sound absorbing materials,
Polyurethane foam has been mainly used for interior materials of trunk rooms and the like. However, polyurethane foam has problems from the standpoint of safety, recyclability, and environmental protection, such as the generation of nitrogen-containing toxic gas during combustion, or the destruction of the ozone layer in the upper atmosphere by Freon gas used during production. Has been pointed out.

[0003] As an alternative material of polyurethane foam,
JP-A-58-31150, JP-A-2-15405
0, JP-A-3-220354, JP-A-3-220354
JP-A-249213 and JP-A-4-240219 propose a solid cotton obtained by blending a short fiber made of polyethylene terephthalate (hereinafter abbreviated as PET) and a polyester-based heat-adhesive fiber. In addition, Japanese Unexamined Patent Publication
For the purpose of improving heat resistance, Japanese Patent Application Laid-Open No. 165884 proposes a solid cotton using polyethylene naphthalate (hereinafter abbreviated as PEN) as a main fiber.

[0004] However, since these solid cottons are in the form of a cushion in which fibers are laminated, they have a low repulsive force against compression and are liable to compression. In order to solve this problem, it is disclosed in Japanese Patent Publication No. 57-48 and Japanese Patent Publication No. Hei 8-48 to improve the sag resistance by forming a fibrous structure in which beads made of beads are laminated to form a fiber structure.
26505, JP-A-9-228218, JP-A-9-228215, and the like.

[0005] In general, as a cushion material for automobiles, it is required that the interior of the car in summer is assumed and that it does not damp even in a high temperature atmosphere of 70 ° C. Since the glass transition temperature (hereinafter abbreviated as Tg) of the fiber is about 70 ° C., the fiber structure made of the ball-shaped cotton is extremely susceptible to compression in a high-temperature atmosphere of 70 ° C. or more. Met. further,
Since the adhesive component of the heat-adhesive fiber for bonding the main fiber is amorphous polyester, the adhesive strength in a high-temperature atmosphere of about 70 ° C. is inferior, and the fiber structure made of the ball-shaped cotton is also in a high-temperature atmosphere of about 70 ° C. It was easy to settle down below.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and provides a beaded cotton which is hard to set even in a high-temperature atmosphere of about 70 ° C. and can obtain a fiber structure excellent in bulkiness. An object of the present invention is to provide a fiber structure.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop a fiber structure made of ball-shaped cotton which is resistant to sagging even in a high-temperature atmosphere. The inventors have found that the object can be achieved by setting the physical properties and fiber physical properties within a specific range, and using a crystalline polymer as an adhesive component of the heat-adhesive fiber, and have reached the present invention.

That is, the present invention provides the following (1) and (2)
It is the gist. (1) a ball-shaped cotton having an average diameter of 3 to 25 mm, comprising 20 to 50% by weight of a crystalline polyester-based thermo-adhesive fiber and 80 to 50% by weight of a polyester-based short fiber;
The polyester-based short fiber is made of polyester having a glass transition temperature of 80 ° C. or more, has a retention rate of a crimp rate of 85% or more before and after heat treatment at 210 ° C., and has a single fiber fineness of 2 to 30 denier. A ball-shaped cotton having a fiber length of 10 to 60 mm. (2) A fiber structure comprising the ball-shaped cotton according to (1).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, it is necessary that the polyester short fiber constituting the ball-shaped cotton of the present invention is made of polyester having a Tg of 80 ° C. or higher. As a result, the fibrous structure made of beaded cotton containing the polyester staple fiber of the present invention as a constituent fiber has a Tg (about 70 ° C.) higher than that of the conventional PET and is 70 ° C.
Under such an atmosphere, the molecular structure is stable, it is difficult to permanently deform even under load, and hard to thermally deform.

When the Tg of the polyester short fiber is less than 80 ° C., the molecular structure becomes unstable due to micro-Brownian motion of the amorphous portion in an atmosphere of about 70 ° C. The fiber structure is easily deformed when subjected to a load, and the resulting fiber structure is also easily deformed by heat and easily sagged.

The Tg used for the polyester short fiber is 80
Polyester above 2.6 ° C is polyethylene-2,6.
-Naphthalate, polyethylene-2,7-naphthalate, poly-1,4-cyclohexylene dimethylene terephthalate and the like. If necessary, terephthalic acid, isophthalic acid, cyclohexanedicarboxylic acid may be used as long as the object of the present invention is not impaired. Acid, adipic acid, sebacic acid,
Bisphenol S or bisphenol A ethylene oxide adduct, cyclohexanedimethanol, 1,4-
Other auxiliary materials such as butanediol, 1,6-hexanediol, diethylene glycol, and polyethylene glycol may be copolymerized, and various additives and the like may be contained.

However, when these copolymer components are contained, the amorphousness increases as the copolymerization amount increases, and T
Since m decreases, heat resistance deteriorates, and the cushioning performance of the fibrous structure obtained by molding the ball-shaped cotton is reduced, the upper limit of the copolymerization amount is preferably about 30 mol%.

The intrinsic viscosity of these polyesters used for polyester short fibers is preferably 0.40 to 0.64, more preferably 0.45 to 0.60.

In the fibrous structure formed by using the ball-shaped cotton of the present invention, the polyester staple fiber constituting the ball-shaped cotton and the thermo-adhesive fiber are thermally bonded, and the ball-shaped cotton is bonded to each other. Thus, a fiber structure is formed. The heat treatment temperature for producing this fiber structure is usually at a temperature not lower than Tm of the adhesive component of the heat-adhesive fiber, and at the highest temperature 50 ° C. higher than the Tm of the adhesive component of the heat-adhesive fiber. Done in Therefore, in the short fiber constituting the ball-shaped cotton of the present invention, it is necessary that the retention rate of the crimp rate before and after the heat treatment at 210 ° C. is 85% or more.

By setting the retention rate of the crimp rate of the polyester short fiber to 85% or more, the crimped form becomes a two-dimensional or three-dimensional structure, and the obtained ball-shaped cotton or fiber structure has a bulky property. It is excellent and hard to be thermally deformed.

When the retention of the crimp rate of the polyester short fiber before and after the heat treatment at 210 ° C. is less than 85%,
After the heat treatment, the crimped form is lost, the fiber becomes linear, and the obtained ball-shaped cotton or fiber structure tends to be one-dimensional, and the bulk is reduced. Further, when the fiber structure is used in a high-temperature atmosphere, the fiber structure is easily deformed by heat.

The number of crimps and the rate of crimp of the polyester short fiber are preferably 5 to 20 crimps / 25 mm and 10 to 30%.

Here, the polyester short fiber is heated at 210 ° C.
In order to make the retention of the crimp rate before and after the heat treatment at 85% or more, it is preferable to manufacture by the following method.
First, melt-spun polyester having a Tg of 80 ° C. or higher,
After this was stretched 3.0 to 5.0 times, the temperature was 100 to 1
A tension heat treatment is performed at 50 ° C., a crimp is applied by a press-in type crimping machine, and then a relaxation heat treatment is performed at 160 to 240 ° C. It is not clear why the retention rate of the crimp rate is increased by this method, but the relaxation heat treatment performed after performing the tension heat treatment and applying the crimp is performed at a temperature higher than the tension heat treatment temperature, thereby maintaining the crimped form. It is presumed that crystallization proceeds in a state of being crimped, and a strong crimp is provided.

The stretching, strain heat treatment, crimping and relaxation heat treatment steps may be performed continuously or in separate steps, and cut into short fibers.

The single fiber fineness of the polyester short fibers is 2
It is necessary to have a denier of 30 to 30 deniers, more preferably 4 to 20 deniers. When the single fiber fineness is less than 2 denier, the diameter of the obtained ball-shaped cotton becomes small, the repulsive force against compression is small, and the residual compression ratio of the obtained fiber structure becomes poor. If the single fiber fineness is greater than 30 denier, it is difficult to bead at the stage of producing the cotton ball.

The fiber length needs to be 10 to 60 mm, and more preferably 20 to 51 mm.
If the fiber length is less than 10 mm, the short fibers are not easily entangled in the production stage of the ball-shaped cotton, so that the fiber length does not become ball-shaped and the fiber length is 6 mm.
If it is larger than 0 mm, it is not a ball but an elongated string.

The cross-sectional shape of the polyester staple fiber in the present invention may have a round cross-section, a triangular cross-section, a flat cross-section, a W cross-section, an H cross-section, a well-shaped cross-section, or a hollow cross-section. Good.

The form of the fiber is not particularly limited as long as the object of the present invention is not impaired. The fiber may be a fiber consisting of polyester alone, or a copolymer of polyester and another component. It may be a side-by-side type.

Next, the crystalline polyester-based heat-adhesive fiber constituting the ball-shaped cotton of the present invention will be described. As the heat bonding component of the heat bonding fiber, Tg is 20 to 80 ° C,
A crystalline copolyester having a Tm of 130 to 180 ° C is preferred. Tm is 2 as a total fusion type fiber composed of only the heat-adhesive component or as a core component.
A core-sheath type conjugate fiber in which a polyalkylene terephthalate having a temperature of 20 ° C. or higher is disposed and the above-mentioned copolymerized polyester is disposed as a sheath component, or a side-by-side type conjugate fiber composed of the above two components may be used. As a specific example, a core-sheath type composite fiber in which PET is disposed as a core component and the above-mentioned copolymerized polyester is disposed as a sheath component is exemplified.

If the copolyester is amorphous, if the ambient temperature exceeds the Tg of the copolyester, the molecular structure becomes unstable, so that the bonded portion does not become strong and the resulting fiber structure Is easily used in a short time or in a high-temperature atmosphere, and does not function as a cushion material. Therefore, it is necessary to use a copolyester having crystallinity for the adhesive component.

If the crystalline copolymerized polyester has a Tg of less than 20 ° C., the yarn-forming properties are poor, such as the occurrence of single yarn adhesion during melt spinning.
It is not preferable because it becomes easy to set under an atmosphere of about 70 ° C. On the other hand, if the Tg exceeds 80 ° C., although it is effective for sag resistance of the fibrous structure, it is necessary to perform stretching at a high temperature in the yarn-making process, and the plastic crystallization due to stretching and partial crystallization occur simultaneously. Starts, and the stretchability decreases, such as the occurrence of yarn breakage, which is not preferable.

If the Tm is less than 130 ° C., there is no heat resistance, so that when the fiber structure is formed, the fiber structure is easily depressed in a high-temperature atmosphere. On the other hand, when the temperature exceeds 180 ° C., a fusion heat treatment at a high temperature is required, and the polymer is likely to be decomposed by the high temperature heat treatment.

Examples of such a copolymerized polyester include:
A terephthalic acid component, an aliphatic lactone component, an ethylene glycol component and a 1,4-butanediol component are used. Aliphatic lactones have 4 to 1 carbon atoms.
One lactone is preferred, and as a preferred lactone, ε-
Caprolactone and δ-valerolactone.

The composition of the copolymerized polyester is selected so as to have the above-mentioned melting point. When an aliphatic lactone is used, its proportion is 10 to 20 mol% of the acid component (total of the terephthalic acid component and the lactone component). It is preferable that

[0030] The fineness and fiber length of the polyester-based thermoadhesive fibers are not limited, but are preferably 2 to 30 denier and 20 to 51 mm in consideration of cushioning properties and entanglement.

The ball-shaped cotton of the present invention is polyester short fiber 8
0 to 50% by weight of crystalline polyester-based heat-bondable fiber 2
0 to 50% by weight.
It is preferable that the polyester-based short fiber is 80 to 70% by weight and the crystalline polyester-based heat-adhesive fiber is 20 to 30% by weight.

If the heat-adhesive fiber content is less than 20% by weight, the number of bonding points between the fibers is small, the fibers are separated, and the compression set of the obtained fiber structure is reduced. On the other hand, if the heat-adhesive fiber content is more than 50% by weight, the ball-shaped cotton becomes too hard,
It is easy to settle for compression.

The size of the ball-shaped cotton of the present invention has an average diameter of 3
It needs to be 25 mm. Average diameter is 3mm
If less than the above, it becomes a nep shape, the bulk performance is inferior, and the compressive stress is poor. On the other hand, if the average diameter exceeds 25 mm, the residual compression ratio of the fibrous structure is inferior, and the uniformity of the ball-shaped cotton deteriorates.

The ball-shaped cotton of the present invention can be obtained by mixing polyester short fibers and crystalline polyester heat-adhesive fibers in an appropriate ratio and stirring the mixture under a high-speed air stream. The size of the ball-shaped cotton can be changed depending on the fineness and the fiber length, but can also be adjusted by adjusting the strength of the airflow and the processing time, and is 2 to 20 m under a high speed airflow of 10 to 50 m / min. By stirring for about a minute, the one having the above size can be obtained.

Next, the fiber structure of the present invention is
Heat-treating the cotton wool and melting the heat-adhesive fibers
It is obtained by bonding. Among them,
Consider cushioning and weight reduction in vehicle seat applications
And a density of 20 to 40 kg / m ^ThreeIt is preferable that

Further, the density of the fiber structure is 20 to 40 k
The 25% compressive stress at g / m3 is preferably 8 kgf or more. If the 25% compressive stress is less than 8 kgf, a feeling of bottom contact occurs, the sitting comfort is poor, and a long-term use causes fatigue of the waist and pain in the buttocks, impairing the comfort and reducing the fibrous structure. It is not preferable because it becomes easy to slip.

It is preferable that the compression set of the fibrous structure at 70 ° C. is 20% or less. 20%
If the temperature exceeds 70 ° C., use of the film in an atmosphere of about 70 ° C. causes a large set, which gives a feeling of bottoming out, which is unfavorable because of poor sitting comfort.

Here, the method for producing the fibrous structure of the present invention will be described by way of an example. The ball-shaped cotton obtained by mixing the polyester-based short fiber of the present invention and the crystalline polyester-based heat-adhesive fiber in an appropriate ratio is uniformly placed in a punching plate form, and the thickness and the packing density are adjusted for the purpose. After the heat treatment, a heat treatment is performed, and the heat-bonding component of the crystalline polyester-based heat-bondable fiber is heat-sealed to produce the fiber.

[0039]

Next, the present invention will be described specifically with reference to examples. The determination of various physical properties in the examples was performed as follows. (1) Tg and Tm Measurement was performed at a heating rate of 20 ° C./min using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer. (2) Fineness Measured according to the method of JIS L-1015-7-5-1A. (3) Fiber length Measured according to the method of JIS L-1015-7-4-1C. (4) Crimp ratio Measured according to the method of JIS L-1015-7-12-2. (5) Retention rate of crimp rate After leaving the obtained short fibers in a hot air drier at a temperature of 210 ° C for 20 minutes, the crimp rate after heat treatment was measured by the method of JISL-1015-7-12-12. did. At this time, the crimp rate after the heat treatment and the crimp rate before the heat treatment were determined by the method (4), and the retention of the crimp rate was determined using the following equation. Retention of crimp rate (%) = (B / A) × 100 A: Crimp rate before heat treatment (%) B: Crimp rate after heat treatment (%) (6) Diameter of ball-shaped cotton The diameter of 50 pieces of ball-shaped cotton was measured with a caliper and determined as the average diameter of 50 pieces. (7) 25% compressive stress A fibrous structure having a density of 25 kg / m ³ and a thickness of 35 mm was prepared as a test piece, and was subjected to the method of JIS K-6401.
The compression force at the time of 25% compression with respect to the initial bulk was measured. (8) Residual compression ratio A square fiber structure having a thickness of 20 mm and a size of 10 cm × 10 cm was prepared as a test piece, and measured by a method of JIS K-6401 (70 ° C. × 22 hours).

Example 1 Polyethylene naphthalate (PEN) having a Tg of 120 ° C. was dried under reduced pressure by a conventional method, and then was spun from a spinneret (number of holes: 120H) at a spinning temperature of 300 ° C. using a spinning apparatus.
The spinning was performed under the conditions of a take-up speed of 500 m / min and a discharge rate of 200 g / min. The obtained unstretched yarn is bundled into a bundle, 100,000-denier tow is stretched at a stretching temperature of 95 ° C., a tension heat treatment temperature of 110 ° C., a stretching ratio of 4.5, and crimped by a push-in crimper. Was given. After that, a finishing oil is applied, a relaxation heat treatment is performed at a dryer temperature of 170 ° C. × 5 minutes, and after cooling, it is cut into a length of 38 mm, and a P denier of 10 denier is formed.
EN short fibers were obtained. Next, as a heat-adhesive fiber, PET having a core component of Tm of 256 ° C., a sheath component of Tg of 32 ° C., and a Tm of 1 were used.
Using a crystalline copolyester at 60 ° C., each was dried under reduced pressure by a conventional method, and then a spinning temperature of 270 ° C. and a take-up speed of 700 m were obtained from a spinneret (number of holes: 639H) using an ordinary two-component composite melt spinning apparatus. / Min, discharge rate 642
Spinning was performed under the conditions of g / min and a composite ratio of 1: 1 (volume ratio during melting) to obtain a core-sheath type composite undrawn yarn. The undrawn yarn is bundled and made into a 100,000 denier tow, and the drawing ratio is 3.8 times.
Stretching was performed at a stretching temperature of 45 ° C. Thereafter, crimping was performed by a press-in type crimping machine and cut to 38 mm to obtain a crystalline polyester-based heat-adhesive fiber having a fineness of 4 denier. The above-mentioned 140 g of the PEN short fiber and 60 g of the crystalline polyester-based heat-adhesive fiber (mixing ratio = 70/30) were weighed and mixed, opened, put into a cotton processing machine, and air-pressured 250 mma
q, stirring was performed for 5 minutes in an air stream at a stirring speed of 30 m / sec to obtain a ball-shaped cotton having a diameter of 5.5 mm. The obtained ball-shaped cotton is uniformly placed in a punched plate form (10 cm × 10 cm) so as to have a thickness of 3.5 cm and a packing density of 25 kg / m ^3, and heat-treated at 210 ° C. for 20 minutes to obtain a fiber structure. I got a body.

Examples 2 to 11 and Comparative Examples 1 to 12 Tg of PEN polymer, fineness, fiber length, adhesive component of heat-adhesive fiber (only Comparative Example 6 was changed), heat treatment temperature in drawing step, heat bonding with PEN fiber Example 1 except that the mixing ratio with the conductive fiber and the diameter of the ball-shaped cotton were changed as shown in Table 1.
In the same manner as in the above method, a PEN short fiber, a ball-shaped cotton and a fiber structure were obtained.

Physical properties of the obtained PEN short fiber and ball-shaped cotton,
Table 1 shows the results of measuring various physical property values of the fiber structure.

[0043]

[Table 1]

As is clear from Table 1, Examples 1 to 11
The fiber structure made of the ball-shaped cotton obtained in the above was excellent in the compressive stress and the compressive residual strain rate, and hardly set even in a high-temperature atmosphere. On the other hand, in Comparative Example 1, since the Tg of the PEN polymer was low, the compressive residual strain rate in an atmosphere at 70 ° C. was high, and it was easy to set. In Comparative Example 2, since the single fiber fineness of the PEN short fiber was small, the diameter of the ball-shaped cotton was also small, the repulsion force against compression was small, and it was easy to set. In Comparative Example 3, since the single fiber fineness of the PEN short fiber was large, the fiber did not bead at the stage of producing the cotton ball, and the cotton ball could not be obtained.
In Comparative Example 4, since the fiber length was short, the fibers did not bead at the stage of manufacturing the ball-shaped cotton, and the ball-shaped cotton could not be obtained. In Comparative Example 5, since the fiber length was long, the fibers were not in a ball shape but in a string shape in the production stage of the ball-shaped cotton, and the ball-shaped cotton could not be obtained. In Comparative Example 6, since the amorphous polyester obtained by copolymerizing 40 mol of isophthalic acid with PET was used as the adhesive component of the heat-adhesive short fiber, the compression set was high and easily set. In Comparative Example 7, the mixing ratio of the PEN staple fiber was large, and the mixing ratio of the heat bonding fiber was too small, so that the adhesiveness was poor.
Peeling between the fibers occurred, resulting in poor compressive stress.
In Comparative Example 8, since the mixing ratio of the PEN short fiber was small and the mixing ratio of the heat bonding fiber was too large, the ball-shaped cotton was hard, and the fiber structure was easy to set. In Comparative Example 9, the compression stress was poor due to the small diameter of the ball-shaped cotton. In Comparative Example 10, the compression stress was small because the diameter of the ball-shaped cotton was large. In Comparative Examples 11 and 12,
Since the crimp retention of the PEN short fibers was low, the fiber structure molded using the ball-shaped cotton was easy to set.

[0045]

EFFECTS OF THE INVENTION The ball-shaped cotton of the present invention has a high Tg and a high shortage of a crimping rate with respect to a high temperature.
Since it is composed of a heat-adhesive fiber having a crystalline heat-adhesive component, the fiber structure made of this ball-shaped cotton is hardly thermally deformed even when used in an atmosphere at a high temperature of about 70 ° C. And a fiber structure having excellent cushioning properties, and is particularly suitable for automobile seat cushions and the like.

Claims (3)

[Claims] 1. A crystalline polyester-based thermoadhesive fiber 20.
50 to 50% by weight and 80 to 50% by weight of polyester staple fiber, and is a ball-shaped cotton having an average diameter of 3 to 25 mm. The polyester staple fiber has a glass transition point temperature of 80 ° C. or more. The retention rate of the crimp rate before and after the heat treatment at 210 ° C. is 85% or more,
Single fiber fineness is 2 to 30 denier, fiber length is 10 to 60 m
m. 2. A fibrous structure comprising the ball-shaped cotton according to claim 1. 3. The fibrous structure according to claim 2, wherein a 25% compressive stress at a density of 20 to 40 kg / m ³ is 8 kgf or more, and a compressive residual strain at 70 ° C. is 20% or less.