JP2001073229A - Polyester-based heat bonding conjugate staple fiber and nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both a polyester-based heat bonding conjugate staple fiber suitable for obtaining a nonwoven fabric having pliability and stretchability and the nonwoven fabric. SOLUTION: This polyester-based heat bonding conjugate staple fiber is a core-sheath type conjugate staple fiber composed of a polyester in which a core part is a polyester comprising a main recurring unit composed of trimethylene terephthalate and a sheath part is a polyetherester comprising a hard segment composed of a polybutylene terephthalate and a soft segment composed of a linear polyalkylene glycol and having <=160 Pa.s melt viscosity at 250 deg.C and 1,000/s shear rate and 160-195 deg.C melting point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polyester-based heat-bondable conjugate short fibers which can impart good flexibility and elastic recovery when used for non-woven fabrics such as dry non-woven fabrics and wet non-woven fabrics. And a non-woven fabric obtained from the short fibers.

[0002]

2. Description of the Related Art Polyurethane foam has been mainly used as a cushioning material for furniture such as sofas, chairs, beds and the like and automobile seats.

However, polyurethane foam has good durability as a cushion, but has a large feeling of flooring.
Poor moisture permeability and easy to stuffy because of heat storage. further,
The amount of heat generated during combustion is large, and it is necessary to add a halide in order to impart flame retardancy, which causes a poisoning problem due to the generation of toxic gas at the time of fire. Polyurethane foam is incinerated because it is difficult to recycle, but there are problems that the incinerator is seriously damaged and it takes a lot of time to remove toxic gas. Further, although the processability is excellent, there is a problem of pollution of chemicals used during the production.

Therefore, in recent years, a fibrous cushion material mainly composed of polyester has been proposed as a material replacing the polyurethane foam. For example, a polyester fiber needling in a web form, a binder,
What has been fused together using fibers (Japanese Patent Laid-Open No. 57-350)
No. 47 publication). There are also polyester fibers bonded with a polyurethane resin.

[0005] However, among the polyester fiber-based cushioning materials, those obtained by needling polyester fibers in a web form have a tendency that some of the fibers fall off and fly, and the bulkiness is insufficient. In order to solve these drawbacks, there is also one that is subjected to fusion processing using a binder-fiber together, but has a drawback that the texture is hard. In addition, both have the drawback that they are susceptible to repeated compression or compression in a high-temperature atmosphere, and the cushioning properties are reduced by use.

[0006] Next, in the case where a cushion material is formed by bonding polyester fibers with a polyurethane resin, it is necessary to considerably increase the ratio of the polyurethane resin, and as with the conventional polyurethane foam, there is a problem of generation of toxic gas during combustion. And poor air permeability.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional heat-bondable short fibers and the nonwoven fabric containing the same, and provides polyester-based heat-bondable short fibers having excellent flexibility and elastic recovery. And to provide a nonwoven fabric thereof.

[0008]

Means for Solving the Problems The present inventors have focused on the constituent polymer of the heat-adhesive conjugate short fiber in order to solve the above-mentioned problems, and have conducted intensive studies. As a result, by using a specific polymer, The inventors have found that the object has been achieved, and have reached the present invention.

That is, the present invention has the following constitutions (1) and (2). (1) A core-sheath type composite short fiber made of polyester, wherein the core is a polyester whose main repeating unit is trimethylene terephthalate, the sheath is a polybutylene terephthalate (PBT) having a hard segment and a soft segment. Consisting of linear polyalkylene glycol,
16 ° C, melt viscosity at a shear rate of 1000 / s is 16
A polyester-based heat-adhesive conjugate short fiber, which is a polyetherester having a melting point of 160 to 195 ° C., which is 0 Pa · s or less. (2) A nonwoven fabric comprising the polyester-based heat-adhesive conjugate short fibers described in (1) above, wherein the nonwoven fabric has an elastic recovery rate of 70% or more at 20% elongation and a softness of 60 cN or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

As the core component of the heat-adhesive conjugate short fiber of the present invention, it is necessary to use a polyester whose main repeating unit is trimethylene terephthalate. Polyester whose main repeating unit is ethylene terephthalate is not preferred because the resulting fiber has a large Young's modulus and poor flexibility.

As long as the effects of the present invention are not impaired, diol components such as 1,4-butanediol and 1,6-hexanediol, aromatic diol components such as an ethylene oxide adduct of bisphenol A, adipic acid Or a copolymer of an aliphatic dicarboxylic acid component such as sebacic acid, an aromatic dicarboxylic acid component such as isophthalic acid, or a stabilizer, a fluorescent agent, a pigment, an antibacterial agent, a deodorant, a reinforcing agent, etc. It may be added.

On the other hand, the sheath component of the heat-adhesive conjugate short fiber of the present invention must be a polyetherester in which the hard segment is composed of PBT and the soft segment is composed of linear polyalkylene glycol. Elastic yarn can be obtained even if the hard segment is made of another polyester, for example, polyethylene terephthalate (PET).
Poor elastic recovery performance, inferior to polyurethane.

The soft segments include polyethylene glycol and polytetramethylene glycol (PT
MG) or the like, and when elastic recovery performance and weather (light) resistance are taken into consideration, PT
MG is preferably used. It is not preferable to use a branched polyalkylene glycol such as polypropylene glycol because the strength is lowered and the elastic recovery performance is deteriorated.

The melting point of the polyetherester used for the sheath must be 160 to 195 ° C. 160
When a material having a temperature of lower than ° C is used, the yarn-forming property becomes poor due to adhesion of the yarn during melt spinning. When the temperature exceeds 195 ° C,
It is necessary to increase the heat treatment temperature during the production of the nonwoven fabric, which is not preferable because the core component is thermally decomposed and causes a decrease in fiber strength.

The melt viscosity of the polymer used for the sheath part is 1 at 250 ° C. and a shear rate of 1000 / s.
It is necessary to be 60 Pa · s or less. It is not preferable to use a material having a viscosity of more than 160 Pa · s measured at 250 ° C. because the elastic recovery performance becomes poor and the elastic properties of the obtained nonwoven fabric become poor. However, if the melt viscosity is too low, yarn breakage tends to occur during melt spinning, so that the pressure is preferably 120 Pa · s or more.

The fineness of the heat-adhesive conjugate short fibers of the present invention is not particularly limited, but is generally 1.5 to 10 d.
Those in the range of tex are preferred. The ratio of the core component to the sheath component is preferably in the range of core / sheath = 20/80 to 95/5.

The heat-adhesive conjugate short fibers of the present invention include, for example,
It can be manufactured as follows. The above core component and sheath component are melt-spun with a commonly used core-sheath type composite spinning device to obtain a core-sheath type heat-adhesive composite undrawn yarn.
Next, after the undrawn yarn is bundled, it is drawn by a conventional method, and if necessary, mechanical crimping is performed by a press-type crimper, and after finishing oil is applied, 3 to 150 depending on the use.
It is obtained by cutting into mm.

Next, the nonwoven fabric of the present invention will be described.
The nonwoven fabric of the present invention needs to include the polyester-based heat-adhesive conjugate short fibers of the present invention. Conventionally, a commonly used core component is PET, and a sheath component is isophthalic acid (I
PA) In the core-sheath type composite short fiber in which a copolymer is disposed,
The elastic properties of the sheath component polymer that bonds the fibers to each other are poor, and the core component is also poor in elastic properties, so the resulting nonwoven fabric has poor elastic recovery,
Not preferred.

Further, the nonwoven fabric of the present invention is composed of the heat-adhesive conjugate fiber of the present invention alone or the main fiber and the heat-adhesive conjugate fiber. It is preferred that the main fiber is 0 to 80% by weight and the polyester-based heat-adhesive conjugate short fiber is 100 to 20% by weight. When the polyester-based heat-adhesive conjugate short fibers are less than 20% by weight, the resulting nonwoven fabric has low tensile strength and low elastic recovery.

The nonwoven fabric of the present invention needs to have an elastic recovery at 70% elongation of 20% or more. If the elastic recovery at 20% elongation is less than 70%, the elastic properties are poor and the effects of the present invention cannot be achieved. Further, the nonwoven fabric of the present invention needs to have a stiffness of 60 cN or less. If the degree of rigidity exceeds 60 cN, the texture of the nonwoven fabric becomes hard, and the effects of the present invention cannot be achieved.

The main fibers are not particularly limited, but polyester short fibers are preferred, and polytrimethylene terephthalate (PTT) short fibers are particularly preferred in view of recyclability and flexibility of the nonwoven fabric.

The nonwoven fabric of the present invention may be either a dry nonwoven fabric or a wet nonwoven fabric. The dry nonwoven fabric can be manufactured, for example, as follows. Main fiber 0-80% by weight
And the polyester-based heat-adhesive conjugate short fiber 100 of the present invention
２０20% by weight, mixed with a carding machine, made into a web, and then subjected to continuous heat treatment at a temperature equal to or higher than the melting start temperature of the sheath component of the polyester-based heat-adhesive conjugate staple fiber +
It can be obtained by performing a heat treatment at a temperature of 30 ° C. or lower.

[0024]

When the main repeating unit of the polyester used for the core of the polyester-based heat-adhesive conjugate short fiber is trimethylene terephthalate, the rigidity becomes smaller than that of PET. The nonwoven fabric obtained is excellent in flexibility and also excellent in flexibility. In addition, when the sheath component is composed of polyetherester, the bonding points between the fibers have elasticity, and the resulting nonwoven fabric has excellent elastic properties.

[0025]

Next, the present invention will be described in detail with reference to examples. The performance evaluation in the examples was measured according to the following method. (1) Single yarn fineness Measured according to the method of JIS L-1015. (2) Weight of nonwoven fabric Measured according to the method of JIS P-8142. (3) Strong nonwoven fabric The nonwoven fabric was cut into a strip having a width of 25 mm and a length of 150 mm to prepare a sample. This sample was made by Orientec U
Using a TM-4 type Tensilon, pulling speed 100 mm
The sample was subjected to elongation cleavage under the condition of / min and the maximum strength was read. In addition, the nonwoven fabric strength passed 650 cN or more. (4) Melting point The melting point was measured at a heating rate of 20 ° C./min using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer. (5) Elastic recovery rate The nonwoven fabric was cut into a strip having a width of 25 mm and a length of 150 mm to prepare a sample. The sample was 100 m long using Orientec Tensilon UTM-4-100.
m, after elongating 20% at a tensile speed of 100 mm / min, returning to the original length at the same speed, and when elongating again, the elongation (E) at which stress appears was determined, and the elastic recovery rate was calculated by the following equation. Elastic recovery (%) = [(20−E) / 20] × 100 (6) Bending resistance (cN) JIS L-1096 sample width 100 mm, sample length 10
Three 0 mm sample pieces were prepared, and DAIEI KEIKI
It was measured with a hand feeling meter (MODELFM-2). 1
A sample piece is placed on a 5 mm wide slit, and when the arm pushes the sample between the slits, the maximum required cN force is measured on the front and back of the sample at four locations in the vertical and horizontal directions, and the total value is calculated. I asked. The average value of three sample pieces was expressed as the softness of the nonwoven fabric, and a softness of 60 cN or less was regarded as acceptable.

EXAMPLE 1 PT having a melting point of 230 ° C. was used as a polymer constituting the core component.
T, as a polymer constituting the sheath component, a weight ratio of 50 /
Consisting of 50 PBT and PTMG having an average molecular weight of 2000, the melting point is 180 ° C, and the melt viscosity at 250 ° C is 130P.
a. s, using a composite spinneret having a core-in-sheath fiber cross-sectional shape, at a melt volume ratio of the core component and the sheath component of 50:50, and a spinning temperature of 270 ° C. It was melt-spun at a discharge rate of 259 g / min, a number of spinning holes of 225 and a spinning speed of 900 m / min, and was cooled at 20 ° C. and 29 Pa of cooling air to obtain an undrawn yarn.

The undrawn yarn is converged, drawn into a tow of 110,000 dtex, drawn at a draw ratio of 2.55 times, at a drawing temperature of 60 ° C., crimped by a push-in type crimper, and cut to obtain a single yarn. A core-sheath type heat-adhesive conjugate short fiber having a fineness of 4.4 dtex and a fiber length of 51 mm was obtained. 30% by weight of this core-sheath type heat-adhesive conjugate short fiber, a fineness of 4.4 dtex, and a fiber length of 51
After mixing 70% by weight of PTT short fibers of 70 mm in weight and making a web with a carding machine, it was subjected to a heat treatment at 130 ° C. for 1 minute by a continuous heat treatment machine to obtain a nonwoven fabric with a basis weight of 50 g / m ² .

Example 2 The mixing ratio of the main fiber and the core-sheath type heat-adhesive conjugate short fiber was 80/2.
Except having changed to 0, it carried out similarly to Example 1, and obtained the nonwoven fabric.

Example 3 The sheath component of the core-sheath type heat-adhesive conjugate short fiber had a melting point of 190.
° C, the melt viscosity is 140 Pa. A core / sheath type heat-adhesive conjugate short fiber and a nonwoven fabric were obtained in the same manner as in Example 1 except that the polyetherester of s was used.

Example 4 The mixing ratio of the main fiber and the core-sheath type heat-adhesive conjugate short fiber was 80/2.
Except having changed to 0, it carried out similarly to Example 3, and obtained the nonwoven fabric.

Comparative Example 1 A heat-bondable conjugate short fiber and a nonwoven fabric were obtained in the same manner as in Example 1 except that the core component of the heat-bondable conjugate short fiber was changed to PET.

Comparative Example 2 A heat-adhesive composite short fiber was prepared in the same manner as in Example 1 except that a polyetherester having a melting point of 202 ° C. and a melt viscosity of 155 Pa · s was used as a sheath component of the core-sheath type heat-adhesive composite short fiber. Fiber and non-woven fabric were obtained.

Comparative Example 3 A heat-adhesive composite short fiber was prepared in the same manner as in Example 1 except that a polyetherester having a melting point of 150 ° C. and a melt viscosity of 120 Pa · s was used as a sheath component of the core-sheath type heat-adhesive composite short fiber. Fiber and non-woven fabric were obtained.

Comparative Example 4 A heat-adhesive composite short fiber was prepared in the same manner as in Example 1 except that a polyetherester having a melting point of 178 ° C. and a melt viscosity of 180 Pa · s was used as the sheath component of the core-sheath type heat-adhesive composite short fiber. Fiber and non-woven fabric were obtained.

Comparative Example 5 A nonwoven fabric was obtained in the same manner as in Example 1 except that the main fiber was PET. Table 1 shows the evaluation results of the nonwoven fabrics obtained in Examples 1 to 4 and Comparative Examples 1 to 5.

[0036]

[Table 1]

As is clear from Table 1, in Examples 1 to 4, nonwoven fabrics having excellent elastic recovery, softness and softness were obtained from the heat-adhesive conjugate short fibers of the present invention.

On the other hand, in Comparative Example 1, since the core component of the heat-adhesive conjugate short fibers was PET, the obtained nonwoven fabric had a low elastic recovery and was inferior in flexibility. Comparative Example 2
The sheath component of the heat-adhesive conjugate short fiber had a high melting point, did not fuse even after heat treatment, and had a low nonwoven fabric strength. Although the heat treatment temperature was further increased, the core component was melted and thermally decomposed, and the nonwoven fabric strength was also low. Comparative Example 3
However, since the melting point of the sheath component of the heat-adhesive conjugate short fiber was low, there were many cohesive yarns at the time of melt spinning, and the yarn-forming property was poor.
Next, in Comparative Example 4, since the melt viscosity of the sheath component was high, the obtained nonwoven fabric was inferior in elastic recovery performance. Furthermore, in Comparative Example 5, since the main fiber was PET, the elastic recovery rate of the nonwoven fabric was low, and the flexibility was poor.

[0039]

As described above, the heat-adhesive conjugate staple fiber of the present invention uses polyester whose main repeating unit is trimethylene terephthalate as the core component, so that the conjugate fiber and the nonwoven fabric obtained therefrom have excellent flexibility. Become. Further, since a polyetherester comprising PBT-PTMG is used as the sheath component, the obtained nonwoven fabric has an excellent elastic recovery rate and can be used as a stretchable nonwoven fabric.

Claims (2)

[Claims] A core-sheath type composite short fiber made of polyester, wherein the core is a polyester whose main repeating unit is trimethylene terephthalate, the sheath is a polybutylene terephthalate having a hard segment and a straight segment having a soft segment. 250 g of chain polyalkylene glycol
16 ° C, melt viscosity at a shear rate of 1000 / s is 16
A polyester-based heat-adhesive conjugate short fiber, which is a polyetherester having a melting point of 160 to 195 ° C., which is 0 Pa · s or less. 2. The polyester thermoadhesive conjugate short fiber according to claim 1, which has an elastic recovery of 70% at 20% elongation.
As described above, the nonwoven fabric has a softness of 60 cN or less.