JP2007162186A - Filament nonwoven fabric and tape of holding and winding electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively obtain a polyester filament nonwoven fabric having excellent tensile strength in the length direction. <P>SOLUTION: In the filament nonwoven fabric, the cross section of a filament constituting the filament nonwoven fabric is an approximately circular cross section, the intrinsic viscosity of the filament is ≥0.61, the nonwoven fabric is a "no-binder" type nonwoven fabric, the warp/weft ratio in the fiber direction is ≥4.0 and the tensile strength per weight in the length direction is >5.0[(N/5cm)/(g/m<SP>2</SP>)]. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a long-fiber nonwoven fabric excellent in tensile strength in the longitudinal direction, and more particularly to a long-fiber nonwoven fabric particularly suitable for use in the field of wire holding tape.

Conventionally, long-fiber non-woven fabrics have been widely used in industry due to an excellent balance of flexibility, strength, price, and the like. The properties required for such long-fiber nonwoven fabrics vary depending on the application. For example, in wire holding tape applications, the process tension during spiral wrap processing is high, and it is particularly resistant to unidirectional deformation applied in the processing process. The tensile strength to be obtained is an important characteristic. Therefore, as a method for producing a polyester long fiber nonwoven fabric having excellent tensile strength in the longitudinal direction, a method in which the strength is improved by performing binder processing is known (for example, see Patent Document 1). However, in these methods, there is a problem that the tape is cut at a weak portion after being cut into a tape shape due to deterioration in uniformity in the width direction due to coating unevenness during binder processing. Further, it is economically disadvantageous and has a problem in wide use in industry.
JP-A-57-56564

  An object of the present invention is to provide a polyester long fiber nonwoven fabric having excellent tensile strength in the longitudinal direction at a low cost.

As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention. That is, in the present invention, (1) the cross-section of the fibers constituting the long-fiber non-woven fabric is a round cross-section, the intrinsic viscosity is 0.61 or more, a non-binder type non-woven fabric, and the aspect ratio in the fiber direction is 4.0. A long-fiber nonwoven fabric characterized by having a tensile strength per unit weight of more than 5.0 [(N / 5 cm) / (g / m ² )]. (2) The long fiber non-woven fabric according to (1) above, wherein the long-fiber non-woven fabric according to (1) or (2) is used, wherein the intrinsic viscosity of the long fiber constituting is 0.80 or more. It was a wire presser winding tape.

  The long-fiber non-woven fabric according to the present invention has the advantage that it has excellent tensile strength in the longitudinal direction without using a special binder, and can be manufactured at low cost by using a general-purpose spinneret using round cross-section fibers.

Hereinafter, the present invention will be described in detail.
It is preferable that the cross section of the fiber constituting the long fiber nonwoven fabric of the present invention is a round cross section. When using a modified cross-section yarn, it is difficult to obtain a nonwoven fabric with excellent tensile strength in the desired longitudinal direction due to excessive pressure bonding and fiber cutting during thermal bonding, and it is difficult to obtain a nonwoven fabric with a general round cross section. This is because it is necessary to change the spinneret and it is economically disadvantageous.

The intrinsic viscosity of the polyester resin constituting the long fiber nonwoven fabric of the present invention is preferably 0.61 or more. More preferably, it is 0.80 or more. If it is less than 0.61, the molecular chain is likely to be broken due to thermal deterioration or the like, and the single yarn strength becomes low, and the resulting nonwoven fabric is difficult to use for the wire holding tape.

It is preferable that the aspect ratio of the strength of the long-fiber nonwoven fabric according to the present invention is 4.0 or more. More preferably, it is 4.5 or more. The strength of the nonwoven fabric is strongly influenced by the number of fibers arranged in that direction. And in normal applications, it is desirable to have a good balance of longitudinal and transverse strength, so that the strength aspect ratio is 1.0 to 3.5, whereas in the case of a wire retainer tape, the strength in one direction is particularly high. Especially required. Therefore, since the number of fibers is limited under the constant basis weight condition of the present invention, it is preferable to arrange more fibers in the longitudinal direction where strength is required. The means for setting the aspect ratio of the strength of the long-fiber nonwoven fabric to 4.0 or more is not particularly limited, but it can be controlled within the target range by controlling the take-up conditions of the nonwoven fabric. In the present invention, when producing a long-fiber non-woven fabric by spinning and stretching polyethylene terephthalate resin from a spinning nozzle, and continuously collecting, depositing and thermally bonding filament groups on a movable collection surface, It is a particularly preferable production method to control the fiber arrangement by adjusting the suction air flow rate to 360 m / min or less.

Although the upper limit of the aspect ratio of the strength of the long-fiber nonwoven fabric is not particularly limited, practical use becomes difficult when it is 10 or more.

The long-fiber nonwoven fabric of the present invention preferably has a tensile strength per unit weight of 5.0 [(N / 5 cm) / (g / m ² )] or more. In particular, in the wire holding tape application, it is used by being wound around a cable or the like. Preferably, it is 5.5 [(N / 5 cm) / (g / m ² )], particularly preferably 6.0 [(N / 5 cm) / (g / m ² )] or more. Strength can be greatly improved by embossed calendering. The pressing area of the embossing calendar is preferably 5% or more, more preferably 8% or more, and particularly preferably 20% or more. Further, it is also preferable to perform smoothing using a plain calendar or the like.

When used as a wire holding tape, the nonwoven fabric is cut into a width of about 5 to 10 cm. Therefore, if the fabric weight distribution of the nonwoven fabric is large, there is a risk of breakage, which is a problem. The CV% of the basis weight distribution when cut across the entire width of 5 cm in width and 20 cm in length at intervals of 5 cm in the width direction is preferably 6% or less, particularly preferably 4% or less. If the basis weight CV% is large, it is necessary to set the basis weight of the nonwoven fabric higher than necessary, which causes problems such as bulkiness.

 EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. The measurement methods used in the examples are as follows.

<Weight per unit (mass per unit area)>
Measured according to JIS-L1906 (2000).

<Tensile strength>
Measured according to JIS-L1906 (2000).

<Aspect ratio>
A value obtained by dividing the tensile strength in the longitudinal direction measured in accordance with JIS-L1906 by the tensile strength in the width direction.

<Tensile strength per unit weight in the longitudinal direction>
A value obtained by dividing the tensile strength in the longitudinal direction measured according to JIS-L1906 by the basis weight.

<Intrinsic viscosity>
Intrinsic viscosity [η] (dl / g) is a value determined based on the definition of the following formula (1).

Ηr in the definition is a value obtained by dividing the viscosity of a diluted solution of polytrimethylene terephthalate yarn or polyethylene terephthalate yarn dissolved in a chlorophenol solvent having a purity of 98% or more by the viscosity of the solvent measured at the same temperature. And is defined as relative viscosity. C is the polymer concentration expressed in g / 100 ml.

Example 1
Polyethylene terephthalate resin (hereinafter abbreviated as PET) having an intrinsic viscosity of 0.80 is spun at a spinning temperature of 290 ° C. with a single-hole discharge rate of 0.7 g / min, and a filament group that is jet-drawn with high-pressure air is mainly composed of polyester. The component is deposited on a resin net moving at a speed of 35 m / min. The collection wind speed at that time was 360 m / min. Thereafter, pressure bonding was performed at 250 ° C. and 50 kN / m with an embossing roller to obtain a spunbonded nonwoven fabric.

(Example 2)
A filament group in which PET having an intrinsic viscosity of 0.63 is spun at a spinning temperature of 285 ° C. with a single hole discharge rate of 0.7 g / min and jet-stretched with high-pressure air is composed mainly of polyester at a speed of 35 m / min. Deposit on the moving resin net. The collection wind speed at that time was 330 m / min. Thereafter, pressure bonding was performed at 250 ° C. and 50 kN / m with an embossing roller to obtain a spunbonded nonwoven fabric.

(Comparative Example 1)
A filament group obtained by spinning PET with an intrinsic viscosity of 0.80 at a spinning temperature of 290 ° C. with a single-hole discharge rate of 0.7 g / min and jet-drawing with high-pressure air at a speed of 35 m / min with polyester as the main component. Deposit on the moving resin net. The collecting wind speed at that time was 600 m / min. Thereafter, pressure bonding was performed at 250 ° C. and 50 kN / m with an embossing roller to obtain a spunbonded nonwoven fabric.

(Comparative Example 2)
A filament group in which PET having an intrinsic viscosity of 0.59 is spun at a spinning temperature of 285 ° C. with a single hole discharge rate of 0.7 g / min and jet-stretched with high-pressure air is a polyester as a main component at a speed of 35 m / min. Deposit on the moving resin net. The collecting wind speed at that time was 600 m / min. Thereafter, pressure bonding was performed at 250 ° C. and 50 kN / m with an embossing roller to obtain a spunbonded nonwoven fabric.

  As is clear from Examples 1 and 2 and Comparative Examples 1 and 2, according to the present invention, a long-fiber nonwoven fabric that is excellent in tensile strength in the longitudinal direction and particularly suitable for specific applications such as a wire holding tape is obtained. I understand that.

  The long fiber nonwoven fabric of the present invention is excellent in tensile strength in the longitudinal direction, and can be provided at low cost using a no-binder type round cross-section yarn. Furthermore, it can be used for printing substrates, separators, especially electric wire press tape application fields, and contributes greatly to the industry.

Claims (3)

The cross-section of the fibers constituting the long-fiber non-woven fabric is a substantially round cross-section, the intrinsic viscosity is 0.61 or more, a non-binder-type non-woven fabric, and the aspect ratio in the fiber direction is 4.0 or more. The long-fiber nonwoven fabric characterized by having a tensile strength per unit weight of more than 5.0 [(N / 5 cm) / (g / m ² )]. The long-fiber nonwoven fabric according to claim 1, wherein the long fiber constituting the fiber has an intrinsic viscosity of 0.80 or more. An electric wire press winding tape using the long fiber nonwoven fabric according to claim 1.