JPH06294015A - Polyester binder fiber - Google Patents

Abstract

PURPOSE:To provide a binder fiber easily producible in the form of fiber and giving a polyester fiber cushioning material having soft feeling and high compression set resistance. CONSTITUTION:This binder fiber is a three-layered sheath-core conjugate fiber having the innermost layer composed of a high-melting polyester having a melting point of >=220 deg.C, an intermediate layer composed of an elastic polyether ester copolymer having a melting point of 130-180 deg.C and the surface layer composed of a polyester having a low softening point, i.e., a softening point higher than 100 deg.C and lower than the melting point of the elastic copolymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester-based binder fiber suitable for a fibrous cushion material which has a soft texture and is hard to be tired even when used for a long period of time.

[0002]

2. Description of the Related Art Conventionally, polyurethane foam has been mainly used as a cushion material for furniture such as sofas, chairs and beds, and a cushion material for automobile seats.
However, polyurethane foam is problematic in terms of safety and global environment, such as generation of nitrogen-containing toxic gas during combustion, and CFC used during manufacturing destroys the ozone layer. Further, the cushioning material has poor breathability and is comfortable, and the polyurethane foam has poor breathability as a cushioning material, which is problematic in terms of comfort.

Therefore, in recent years, a fibrous cushion material mainly composed of polyester fibers has been proposed as a material replacing polyurethane foam. For example, a polyester fiber that is needling in a web form or a binder fiber is used in combination with a fusion process (Japanese Patent Laid-Open No. 35047/1982).
No.) There is also a polyester fiber bonded with a polyurethane resin.

However, among the polyester fiber type cushioning materials, those obtained by needling the polyester fibers in the form of a web were liable to have some of the fibers falling off and scattering, and the bulkiness was insufficient. The fusion-bonded material using binder fibers together does not have such a defect, but has a defect that the texture is hard. In addition, both are easy to get tired against repeated compression and compression in high temperature atmosphere,
There is a drawback that the cushioning property is deteriorated by use. Furthermore, in the case of a cushion material made by bonding polyester fibers with a polyurethane resin, it is necessary to considerably increase the ratio of the polyurethane resin, and as with conventional polyurethane foam, the problem of generation of toxic gas during combustion and poor air permeability. Had the problem of.

Further, as a binder fiber capable of imparting excellent elastic properties and shape retention to the cushion material made of polyester fiber, a polyester-based composite fiber containing a specific polyether ester-based elastic copolymer as an adhesive component. Has been proposed (Japanese Patent Laid-Open No. 4-240219). However, when trying to fiberize such a low-melting-point polyether ester-based elastic copolymer, the problem of adhesion of fibers due to the difficulty of cooling in melt spinning and the surface-friction force in the spinning process are large. There were problems such as scratch damage.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to provide a polyester binder fiber which provides a polyester cushion material having a soft texture and sag resistance.

[0007]

Means for Solving the Problems The present invention is intended to solve the above problems, and its gist is a three-layer core-sheath composite fiber, the innermost layer of which is a high melting point polyester having a melting point of 220 ° C. or higher, and an intermediate layer. Is a polyester ester elastic copolymer having a melting point of 130 to 180 ° C., and the surface layer is composed of a polyester having a softening point of 100 ° C. or more and a low softening point of not more than the melting point of the elastic copolymer, and a polyester binder fiber. It is in.

The present invention will be described in detail below. The high melting point polyester constituting the innermost layer in the present invention,
It is the central component of the binder fiber, and from the viewpoint of stabilizing the spinnability and stability during fusion heat treatment.
It is necessary to have a melting point of not less than ° C. Specific examples of such polyesters include polyethylene terephthalate and polyalkylene terephthalates such as polybutylene terephthalate, and other components may be copolymerized in a small amount within a range not impairing the effects of the present invention,
It may contain additives such as matting agents and lubricants.

The polyether ester elastic copolymer constituting the intermediate layer is a block copolymer of a hard segment made of crystalline polyester and a soft segment made of polyalkylene ether, and has a melting point of 130 to 180 ° C. It needs to be one. If the melting point of the elastic copolymer is less than 130 ° C, even if it is made into fibers, it tends to be tired when used in a high-temperature atmosphere, while if it exceeds 180 ° C, it is necessary to perform the fusion heat treatment at a high temperature. In addition to being unfavorable, heat treatment tends to cause decomposition of the polymer.

The melting point of the elastic copolymer is adjusted by appropriately selecting the kind and copolymerization composition of the polyester forming the hard segment, the average molecular weight of the polyalkylene glycol of the soft segment, and the ratio of the hard segment and the soft segment. can do.

As the hard segment, a polyalkylene terephthalate such as polyethylene terephthalate or polybutylene terephthalate, or a copolymer or mixture thereof is preferably used.

As the soft segment, polyalkylene glycol having an average molecular weight of 500 to 5000, preferably 1000 to 3000 is used. If the molecular weight of the polyalkylene glycol is less than 500, sufficient elastic properties cannot be obtained, and if it exceeds 5,000, the compatibility with the hard segment deteriorates, a uniform polymer cannot be obtained, and the elastic properties also deteriorate. To do. Specific examples of the polyalkylene glycol include polyethylene glycol and polytetramethylene glycol.

The ratio of the hard segment to the soft segment is preferably in the range of 20/80 to 60/40 by weight in order to obtain excellent elastic properties and suitable melting point.

The elastic copolymer has an elongation of 100 to 800%, an elastic recovery rate of 50% elongation of 90% or more, and an elastic recovery rate of 200% elongation of 75 when it is used alone as a drawn yarn. Those having elastic properties of not less than% are preferable.

The low softening point polyester constituting the surface layer has the function of improving the spinnability at the time of spinning and needs to be melted faster than the elastic copolymer of the intermediate layer which is the main fusion component during the fusion heat treatment. And has a softening point of 100 ° C. or higher and the melting point of the elastic copolymer or lower. If the softening point of the low softening point polyester is less than 100 ° C., it becomes difficult to form a yarn and the heat resistance of the final product is lowered, which is not preferable.

The low softening point polyester can be obtained by copolymerizing polyethylene terephthalate or polybutylene terephthalate with another dicarboxylic acid or another glycol. Specific examples of such dicarboxylic acids and glycols include isophthalic acid, phthalic acid, adipic acid, sebacic acid, ethylene glycol, 1,4-butanediol, diethylene glycol and triethylene glycol.

In the three-component core-sheath type composite fiber of the present invention,
The composite ratio may be selected so that the three components exhibit their respective functions, but usually, the innermost layer component is 20 to 50% by volume, the intermediate layer component is 30 to 60% by volume, and the surface layer component is 13 to 25% by volume. %.

In the binder fiber of the present invention, the above-mentioned three components are melt-spun using a conventional three-component core-sheath type composite fiber spinning device, and the obtained unstretched fiber is stretched and subjected to tension heat treatment, It can be manufactured by applying crimps as necessary.

The binder fiber of the present invention, as a short fiber, is mixed with normal polyester fiber, natural fiber such as cotton, wool, palm fiber, etc. to form a web with a card or the like, and heat treated to produce a low softening point polyester and an elastic material. A cushion body is formed by melting the copolymer and spot-bonding the constituent fibers. In this case, needling may be performed before the heat treatment.

Further, a web may be formed by a method in which ordinary long fibers or tows such as polyester are mixed with the long fiber binder fibers of the present invention and the fibers are opened.

As the heat treatment apparatus, a hot air circulation dryer, a hot air once-through dryer, a suction dryer, etc. are used, and the heat treatment is performed by selecting the treatment temperature and the treatment time according to the melting points of the low softening point polyester and the elastic copolymer. Just go.

[0022]

[Effects] Polyetherester-based elastic copolymers have poor cooling properties during melt spinning, fibers may stick to each other, and the large surface friction force causes friction damage on guides, rolls, etc. Wake up. In the present invention, such a problem is solved because the surface of the elastic copolymer is coated with the low softening point polyester. Further, since the binder fiber of the present invention has the high melting point polyester disposed in the innermost layer, the fiber has high strength and good spinnability. Furthermore, since the binder fiber of the present invention has an appropriate melting point and elasticity, a fiber cushion body using this as a binder fiber has a soft texture and is resistant to repeated compression and compression in a high temperature atmosphere. It becomes difficult to get tired.

[0023]

EXAMPLES Next, the present invention will be specifically described with reference to examples. The methods for measuring and evaluating various properties are as follows. (1) Relative viscosity Using an equal weight mixed solvent of phenol and ethane tetrachloride,
It was measured at a concentration of 0.5 g / dl and a temperature of 20 ° C. (2) Melting point Using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elmer, the melting point was measured at a temperature rising rate of 20 ° C / min. (3) Softening point Using a hot stage manufactured by METTLER CO., LTD., The temperature was raised at a heating rate of 2 ° C./minute, and the softening start temperature was measured by observing with a microscope. (4) Settling resistance during repeated compression (according to JIS K 6382 5.6.3) After measuring the thickness t ₀ of the test piece, it is sandwiched between parallel compression plates on both sides, and the speed is 60 times per minute at room temperature. To 50% of the thickness of the test piece
After repeatedly compressing 80,000 times, the test piece was taken out and allowed to stand at room temperature for 30 minutes, the thickness t ₁ thereof was measured, and the cyclic compression residual strain rate C (%) was calculated by the following formula and evaluated. (Represented by the average value of three test pieces.) C = [(t ₀ −t ₁ ) / t ₀ ] × 100 (5) Settling resistance under high temperature atmosphere (according to JIS K 6382 5.5.2). After measuring the thickness t ₀ of the test piece, it is sandwiched between compression plates parallel to both sides, compressed and fixed at 50% of the thickness of the test piece, and the temperature is 70 ± 1 ° C.
Of removed after heating continuously for 22 hours in a constant temperature bath, remove the test pieces from the compression plate, allowed to stand at room temperature for 30 minutes, the thickness t ₂
Was measured, and the compressive residual strain rate CT (%) was calculated by the following formula and evaluated. CT = [(t ₀ −t ₂ ) / t ₀ ] × 100 (6) Feeling A sensory test by 10 panelists evaluated the following three grades. (Shown as an average value.) 1: Soft, 2: Normal, 3: Hard

Examples 1 to 4 and Comparative Example 1 The following three component pellets were each dried under reduced pressure to form a yarn. Innermost layer: polyethylene terephthalate (relative viscosity 1.38,
Melting point 256 ° C) Intermediate layer: Block copolymer of polybutylene terephthalate and polytetramethylene glycol having a molecular weight of 1000 with a weight ratio of 40/60 (relative viscosity 2.02, melting point 162 ° C) Surface layer: 33 mol% of isophthalic acid Polyethylene terephthalate copolymer (relative viscosity 1.35, softening point 131
℃) Using a concentric three-component composite melt spinning device, at the composite ratio (volume ratio) shown in Table 1, spinning temperature 270 ° C., discharge rate 206 g / min, spinning hole number 225, spinning speed 700 m / min. , 18 ° C
Cold wind was blown to cool and take it off to obtain an undrawn yarn. The obtained undrawn yarn was bundled into a tow of 100,000 d, drawn at a draw ratio of 3.2 times, drawn at a drawing temperature of 65 ° C, subjected to a tension heat treatment at a temperature of 120 ° C, and then crimped with a push-in type crimper. Then, it was cut into a length of 51 mm to obtain a binder fiber having a fineness of 4d. Table 1 shows the situation in which the fibers of the undrawn yarn are closely attached to each other, the weight loss rate during spinning (the rate of weight loss due to rubbing until the spun yarn is made into the binder fiber), and the strength of the binder fiber. In Comparative Example 1 (two-component composite fiber), the undrawn yarns were often brought into close contact with each other, and the weight reduction rate at the time of yarn making was large, so that satisfactory fibers could not be obtained.

[0025]

[Table 1]

Examples 5 to 10 and Comparative Examples 2 to 4 Binder fibers composed of three-layer composite fibers with a composite ratio (volume ratio) of 40/45/15 in the same manner as in Example 1 using the following three components. Got Innermost layer: polyethylene terephthalate (relative viscosity 1.38,
Melting point 256 ° C.) Intermediate layer: elastic copolymer having composition and characteristic values shown in Table 2 Surface layer: low softening point polyester (polyethylene terephthalate copolymer copolymerized with isophthalic acid having composition and characteristic values shown in Table 2) )

[0027]

[Table 2]

Reference Example 70:30 of 14 kinds of binder fibers obtained in the above Examples and Comparative Examples and ordinary polyethylene terephthalate composite fiber for wadding (fineness 13d, fiber length 51 mm, hollowness 15%)
After blending in the weight ratio of, and making it into a web with a carding machine, it was laminated with a cross layer to obtain a laminated web with a basis weight of 1.25 kg / m ^2. This web was regulated to a thickness of 5 cm, and a hot air circulation dryer was used. At 180 ° C. for 15 minutes, a fibrous cushion body having a thickness of 5 cm was obtained. Table 3 shows the sag resistance (C) during repeated compression, the sag resistance (CT) in a high temperature atmosphere, and the texture of the obtained cushion body. Since the cushion body using the binder fiber of Comparative Example 2 had poor adhesion, when the heat treatment temperature was raised to 195 ° C., the heat deterioration was remarkable and it could not be put to practical use.

[0029]

[Table 3]

[0030]

Industrial Applicability According to the present invention, there is provided a binder fiber which provides a polyester fiber type cushioning material which is easy to be fiberized and has a soft texture and sag resistance.

Claims (1)

[Claims] 1. A three-layer core-sheath composite fiber, wherein the innermost layer is a high melting point polyester having a melting point of 220 ° C. or higher, and the intermediate layer is a melting point of 130.
A polyester-based binder fiber characterized by comprising a polyetherester-based elastic copolymer having a softening point of up to 180 ° C. and a surface layer made of a low-softening point polyester having a softening point of 100 ° C. or higher and a melting point of the elastic copolymer or lower.