JP3333635B2 - Method for producing ultrafine long-fiber nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a nonwoven fabric made of ultrafine fibers. For more information,
The present invention provides a novel bicomponent bicomponent composite fiber having a cross-sectional shape in which each component is divided into a plurality of segments by the other component. The present invention relates to a method for producing an ultrafine long-fiber nonwoven fabric.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a method of obtaining various types of bicomponent conjugate fibers on a net and then treating the collected bicomponent conjugate fibers to obtain ultrafine long fibers. For example, Japanese Patent Publication No. Hei.
Japanese Patent No. 3555 discloses a method of obtaining a nonwoven fabric made of ultrafine fibers by applying mechanical stress to a collected aggregate of split type composite fibers to split the composite fibers. Further, Japanese Patent Publication No. 41316/1987 discloses a method of obtaining a nonwoven fabric made of ultrafine fibers by dissolving and removing only the sea component by treating the collected sea-island type composite fiber aggregate with a solvent. However, in the former method, since the proportion of the portion that is not split in the fiber length direction and the cross-sectional direction is relatively large, the obtained nonwoven fabric has a rough feeling and has a problem in terms of feeling, and at the same time, the production process is difficult. Has the disadvantage of being complex. On the other hand, in the latter method, since one component of the conjugate fiber is dissolved and removed with a solvent or the like, there is a disadvantage that a manufacturing process including a step of recovering the solvent or the like is complicated and a manufacturing cost is increased.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel production method which solves the above-mentioned problems of the prior art and which can easily and stably obtain a fine nonwoven fabric of high quality. With the goal.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a split mold 2 composed of a fiber-forming polyester and a fiber-forming polyamide.
The component-based composite undrawn yarn can be split in the composite fiber mainly by the second-stage drawing process by performing the two-stage drawing under specific conditions, and this is opened and deposited on the collecting surface. The present inventors have found that an ultrafine long-fiber nonwoven fabric having no coarse and hard feeling can be stably obtained only by performing the above method, and the present invention has been reached.

That is, the method for producing a nonwoven fabric according to the present invention comprises:
Melt-fibre spinning the fiber-forming polyester (A) and the fiber-forming polyamide (B) into splittable bicomponent conjugate fibers having a fiber cross-sectional shape in which each component is divided into a plurality of other components; After the obtained unstretched yarn is first-stretched to 1.0 to 1.2 times its natural draw ratio (NDR),
It is made into split filaments by performing second-stage stretching so that the total draw ratio is 1.3 to 1.6 times the natural stretch ratio, and then the split filaments are placed on the collecting surface by air sucker. This is a method for producing an ultrafine long-fiber nonwoven fabric, which is characterized by spreading and depositing.

Examples of the fiber-forming polyester used in the present invention include polyesters such as polyethylene terephthalate, polybutylene terephthalate and copolymer polyesters containing these as a main component.
On the other hand, examples of the fiber-forming polyamide include polyamides such as nylon 6, nylon 46, nylon 66, nylon 610, and copolymer nylon containing these as a main component. In addition, these polyesters or polyamides, respectively, a normal matting agent, heat stabilizer,
An additive such as a pigment may be added.

In the present invention, the above-mentioned fiber-forming polyester (A) and fiber-forming polyamide (B) are melt-conjugated and spun to form an undrawn split-type bicomponent composite fiber. Here, the cross-sectional shape of the conjugate fiber is arbitrary as long as the component A and the component B are each divided into a plurality of components by other components. In particular, as shown in FIG. 1, the component B exhibits a petal shape. In addition, a form in which each petal is exposed on the surface of the composite fiber is preferable, and the total number of divided A and B components is preferably in the range of 8 to 32. When the number of segments is less than 8, it is difficult to reduce the single yarn fineness after splitting, while when it exceeds 32, the process stability tends to decrease. In addition, as shown in FIG.
Even if one component is divided into a plurality by the other component,
In the case of a form completely covered with the other component, or in a form in which one component is joined and integrated as shown in FIG. 3, splitting becomes difficult to progress and the obtained nonwoven fabric Also tends to decrease. For this reason,
The composite ratio of the component A and the component B is 40:60 to 60:40.
(Weight ratio).

The fineness of the composite fiber is such that the fineness of the split long fiber obtained by the stretching treatment described below is 0.8 denier or less.
Preferably 0.5 denier or less, more preferably 0.3 denier
It is desirable that the denier is not more than denier, and if the fineness of the split filaments exceeds 0.8 denier, the hand of the obtained nonwoven fabric tends to decrease. In addition, if the single fiber fineness of the composite fiber is less than 1 denier after drawing assuming that splitting is not performed, it becomes difficult to stably perform composite spinning.

The conjugate fiber having the cross-sectional shape may be melt-spun using a conventionally known melt-spun apparatus. For example, four or more molten polyamides (B) may be guided into the introduction holes of the molten polyester (A), and composite spinning may be performed using a composite spinneret having a structure that is discharged from a nozzle hole together with the polyester (A).

In the present invention, the unstretched yarn obtained by the composite spinning is liable to be broken when the drawing temperature is too low, whereas the mechanical properties of the obtained fiber tend to decrease when the drawing temperature is too high. The stage stretching temperature is 50 to 80 ° C, preferably 7
The second-stage stretching is performed at 0 to 80 ° C and the second-stage stretching temperature is 90 to 110 ° C, preferably 90 to 100 ° C. that time,
The first stage stretching ratio is 1.0 of the natural stretching ratio (NDR).
To 1.2 times, preferably 1.1 to 1.2 times, and the total stretching ratio is 1.3 to 1.6 times the natural stretching ratio.
It is important that it is preferably in the range of 1.4 to 1.6 times.

When the draw ratio of the first stage is less than NDR, the composite fiber is not split sufficiently even if the draw ratio of the subsequent second stage is increased. It becomes unsatisfactory in appearance. Conversely, NDR 1.
If it exceeds twice, problems such as thread breakage and winding around a draw roll occur, and the uniformity of the obtained nonwoven fabric decreases. On the other hand, when the total draw ratio is less than 1.3 times the NDR, the ratio of split fibers becomes insufficient, so that the obtained nonwoven fabric has a rough and hard feeling, and conversely, the NDR is less than 1.3. When the ratio exceeds 6 times, the splitting ratio of the conjugate fiber is sufficient, but the yarn breakage occurs frequently, and it is difficult to obtain a stable and uniform quality nonwoven fabric.

In the present invention, the first-stage stretching may be further divided into a plurality of stages of two or more stages and may be performed in multiple stages. In the case where the film is divided into a plurality of portions, the final stage stretching is performed). When the second-stage drawing is performed by dividing into two or more stages, the split ultrafine fibers tend to be easily wound around a drawing roller or the like.

In the second-stage drawing, as shown in FIG. 4, for example, the second-stage drawing while squeezing the fiber between the first drawing roller and the second drawing roller is performed according to the splitting ratio of the composite fiber. It is preferable in improving the value. Here, stiffening the fiber can be achieved by rubbing the fiber with a pair of guides,
These guides may be made of ceramic or metal, and may be rotatable.

Next, the split ultrafine long fibers made of polyester (A) and ultrafine long fibers made of polyamide (B) are collected by air soccer, and then electrostatically or aerodynamically separated as required. The web is spread and collected as a random and uniform web (nonwoven fabric) on a collection surface such as a web conveyor.

The collected ultrafine long-fiber non-woven fabric may be partially heat-sealed between fibers by a heating roll using a fiber made of a polymer having a lower melting point. May be entangled,
Further, the adhesive treatment may be performed by impregnating with an adhesive liquid. Further, various treatments for improving flexibility, water repellency and the like of the nonwoven fabric may be performed.

[0016]

According to the production method of the present invention, the splittable bicomponent composite fiber in which the polyester and the polyamide are composited is drawn in two steps under specific conditions, so that the draw ratio is large. In the first-stage stretching, the fiber can be stretched without causing much splitting, while in the second-stage stretching, a sufficient peeling stress acts on the joint surface between the polyester and the polyamide, and the splitting can be performed. In addition, since split filaments are spread and deposited on the collecting surface after being taken up by air soccer, split filaments are unlikely to be broken even though they are ultrafine fibers. It is possible to easily obtain a stable and uniform ultrafine long-fiber nonwoven fabric.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. In addition, the measuring method in an Example followed the following method. Intrinsic viscosity: The intrinsic viscosity of polyester was measured at a temperature of 35 ° C. using orthochlorophenol as a solvent. The intrinsic viscosity of polyamide is determined by using m-cresol as a solvent at a temperature of 35.
Measured in ° C.

Splitting ratio: Ten cross-sectional photographs of the web accumulated on the net were taken, the number of segments in which the composite fiber was separated and separated was counted, and expressed as a ratio (%) to the total number of segments.

NDR (natural stretch ratio): The undrawn yarn is allowed to stand in an atmosphere maintained at a temperature of 20 to 30 ° C. and a relative humidity of 50 to 70% for 24 hours, and then at 20 ° C. using an Instron tensile tester. It was measured at a pulling rate of 1000% / min under 65%.

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.64 was melted at 290 ° C., and nylon 6 having an intrinsic viscosity of 1.1 was melted at 250 ° C. to obtain a composite fiber having a sectional shape shown in FIG. The resulting composite spinning hole is 270
Using a spinneret having holes, melt-spinning was performed at a discharge rate of 150 g / min so that the composite ratio was 1: 1.
After the spun yarn is cooled and solidified by cooling air,
It was taken off at a speed of 1100 m / min with a take-off roll heated to 0 ° C to obtain an undrawn yarn.

The drawn undrawn yarn is drawn in the first stage at a magnification shown in Table 1 between a first drawing roll heated to 90 ° C. without being wound once and then continuously. ,
Subsequently, the second drawing was performed between the first drawing roll and the second drawing roll heated to 120 ° C. so that the total drawing ratio was as shown in Table 1, to obtain split filaments.

The split filaments were sucked by air soccer, collided with the dispersion plate and charged at the same time to open the fibers, and deposited on the moving web conveyor surface to obtain a long-fiber nonwoven fabric (web). The results are shown in Table 1. In addition, 1100
The undrawn yarn taken at a speed of m / min was sampled, and the natural draw ratio was measured to be 2.52.

[0023]

[Table 1]

Example 2 Using a spinneret having 360 composite spinning holes, a discharge rate of 420 g / min and a take-off speed of 1
A long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that 200 m / min, the composite ratio of polyethylene terephthalate and nylon 6, and the stretching ratio were changed as shown in Table 2. Note that the experiment No. In No. 15, stretching was carried out in the apparatus shown in FIG. The results are shown in Table 2.

[0025]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a splittable bicomponent conjugate fiber according to the present invention.

FIG. 2 is a cross-sectional view showing an example of a bicomponent conjugate fiber outside the present invention.

FIG. 3 is a cross-sectional view showing another example of a bicomponent conjugate fiber outside the present invention.

FIG. 4 is a schematic diagram illustrating an example of the production method of the present invention.

[Description of Signs] 1 supply roller 2 first stretching roller 3, 3 'guide 4 second stretching roller 5 air sucker A fiber-forming polyester B fiber-forming polyamide Y composite fiber

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-213555 (JP, A) JP-A-3-76818 (JP, A) JP-A-5-25762 (JP, A) JP-A-7- 126922 (JP, A) JP-A-4-300351 (JP, A) JP-A-5-186946 (JP, A) JP-A-5-140849 (JP, A) JP-A-3-69612 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) D04H 1/00-18/00 D01F 8/14

Claims (3)

(57) [Claims] 1. A split mold 2 comprising a fiber-forming polyester (A) and a fiber-forming polyamide (B) each having a fiber cross-sectional shape in which each component is divided into a plurality of other components.
The composite yarn is melt-spun into a multicomponent fiber, and the obtained undrawn yarn is first stretched to 1.0 to 1.2 times its natural draw ratio (NDR).
After step stretching, the total stretching ratio is 1.3 to the natural stretching ratio.
Extra-fine long-fiber nonwoven fabric characterized in that split second fibers are formed by drawing in the second step so as to be 1.6 times, and then the split long fibers are spread and deposited on a collecting surface by air soccer. Manufacturing method. 2. The splittable bicomponent conjugate fiber has a fiber cross-sectional shape in which a fiber-forming polyester (A) and a fiber-forming polyamide (B) are alternately arranged radially around a fiber axis. A method for producing the ultrafine long-fiber nonwoven fabric according to claim 1. 3. The method for producing an ultrafine long-fiber nonwoven fabric according to claim 1 or 2, wherein the fibers are drawn in the second step while being squeezed to form split long fibers.