JP3391934B2 - Splittable fiber and fiber sheet using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a splittable fiber and a fiber sheet material using the splittable fiber.

[0002]

2. Description of the Related Art When ultrafine fibers having a fineness of 0.5 denier or less are used as the constituent fibers of a fibrous sheet, the feeling, the filtration performance, the liquid retention, the heat retention, etc. can be improved. Ultrafine fibers are preferably used because various properties are improved. As one of the methods for obtaining this ultrafine fiber, there is a method of dividing a splittable fiber which has a fineness of 1 denier or more and can be split into ultrafine fibers by a mechanical external force. Since it was composed of different series of resin components with low compatibility, when divided,
It is a mixture of ultrafine fibers composed of resin components of different series, and a fiber sheet-like article composed only of ultrafine fibers composed of resin components of the same series is not suitable for suitable use.

Therefore, a splittable fiber in which a polyolefin component having a specified Rockwell hardness is combined (Japanese Patent Publication No.
-63129) or a splittable fiber composed of a polypropylene component and a component obtained by mixing high-density polyethylene in the polypropylene component (JP-A-5-321018).
Is proposed. However, all the splittable fibers had insufficient splittability.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a splittable fiber composed of a resin component of the same series, which is easy to split, and uses the splittable fiber. The purpose of the present invention is to provide a fibrous sheet-shaped product.

[0005]

The splittable fiber of the present invention comprises:
It consists of a split resin component in which a highly elastic resin with a flexural modulus of 1.8 × 10 ⁴ kg / cm ² or more is mixed, and a split resin component that is roughly split into two or more by this split resin component, and The resin component and the resin component to be divided are polyolefin resin components. The fiber sheet material of the present invention contains ultrafine fibers obtained by dividing the splittable fiber.

[0006]

In the splittable fiber of the present invention, a highly elastic resin having a flexural modulus of 1.8 × 10 ⁴ kg / cm ² or more is mixed in the split resin component, and moreover, the split resin component is used to separate the split resin component. Two
Since it is roughly divided into three or more parts, when a mechanical external force is applied, a distortion occurs between the divided resin component and the resin component to be divided, and it is easy to divide.

The splittable fiber of the present invention is composed of the same type of resin component, and when the splittable fiber is split, only ultrafine fibers of the same series of resin component are obtained. It can also be used for applications that were not applicable in the past. For example, polypropylene and polyethylene, polymethylpentene and polypropylene, polymethylpentene and polyethylene and other polyolefin resins, and 6 nylon and 66 nylon and other polyamide resins , Polyester-based resins such as polyethylene terephthalate and polybutylene terephthalate. Among them, a fiber sheet material containing ultrafine fibers obtained by dividing the splittable fibers composed of polyolefin-based resins is excellent in electrolytic solution resistance, and is used as a separator for batteries, or because it is easily electretized and is used as a filter cloth. Can be suitably used.

In the splittable fiber of the present invention, the resin component to be split is roughly split into two or more by the split resin component. The split state by this split resin component extends radially from the fiber axis,
A description will be given with reference to FIG. 1 showing a sectional shape divided by a divided resin component having a fan shape. For example, a resin of a type different from the resin component (b) and the resin component (p) in which the resin component (a) is adjacent (A) resin component and (c) resin component (a) and (c) resin component different from the adjacent (b) resin component and (d) resin component.
The resin component is in a state of being divided into two resin components to be divided, and the resin component (a) and the resin component (c) can be considered as divided resin components. Further, in this case, the resin component (b) and the resin components (d) to (p) can be considered as the divided resin components. This splittable fiber is divided into (a)
An ultrafine fiber made of a resin component, (b) an ultrafine fiber made of a resin component, and (c) an ultrafine fiber made of a resin component,
It is possible to obtain ultrafine fibers composed of the resin components (d) to (p). Therefore, when the divided resin component is adjacent to the non-divided resin component and the non-divided resin component is adjacent to the divided resin component, finer ultrafine fibers can be obtained, which is a preferable arrangement state of the divided resin component. In addition, it is not necessary that the resin constituting the divided resin component or the divided resin component is of one type. Hereinafter, description will be made also with reference to FIG. 2 showing a cross-sectional shape composed of two kinds of resin components, that is, a divided resin component 1 and a divided resin component 2.

The split resin component 1 or the split resin component 2 is
As shown in FIGS. 1 and 2A to 2C, when radially extending from the vicinity of the fiber axis, a mechanical external force uniformly acts on both of the divided resin component 1 and the divided resin component 2. It is suitable because it can be easily divided. Further, as shown in FIG. 2D, a large number of divided resin components 1 and divided resin components 2 may be laminated, or the divided resin component 1 may be H-shaped, K-shaped, A-shaped or E-shaped in the alphabet. , F shape, L shape, M shape, N shape, T
The shape may be a V shape, a W shape, a Z shape, or the like. The divided resin component 1 may divide the resin component 2 to be divided into any number, but the fineness of the ultrafine fibers obtained by dividing the splittable fibers is more preferably 7 × 10 ^{−5 to} 0.5 denier. Is 2 × 1
It is preferable to divide it so as to have a denier of 0 ^{−4 to} 0.3.

Further, as shown in FIGS. 1 and 2 (b),
The divided resin component 1 or the divided resin component 2 may have a fan-shaped cross section, or may have a uniform thickness and extend from the vicinity of the fiber axis. The divided resin component 1 or the divided resin component 2 does not have to extend linearly, and may extend in a curved shape, but it is preferable that the divided resin component 1 or the divided resin component 2 extends linearly from the viewpoint of dividing property.

The division of the resin component 2 to be divided by the resin component 1 does not need to be completely divided, but is divided to such an extent that it can be divided by a mechanical external force, that is, a distance of 2 from the fiber axis to the fiber surface. It suffices if the split resin component 1 is present at a position closer to the fiber surface than one-third, more preferably at a position closer to the surface than two-thirds, and most preferably at the fiber surface. Existing.

As the cross-sectional shape of the fiber, a circular cross-section is illustrated in FIGS. 1 and 2, but it need not be circular, but may be polygonal such as triangle or quadrangle, ellipse, oval, gourd. A modified cross-sectional shape such as This cross-sectional shape can be easily changed depending on the shape of the spinning orifice when spinning the fiber.

Although the conventional splittable fiber composed of the same type of resin component is difficult to split, the splittable fiber of the present invention has a flexural modulus of 1.8 × 10 ⁴ kg / cm ^{2 in the} split resin component. Since the above high-elasticity resins are mixed, excellent splittability is obtained, and ultrafine fibers can be easily obtained. If the flexural modulus of this high-elasticity resin is less than 1.8 × 10 ⁴ kg / cm ^2, it is difficult to divide, and more preferably, the flexural modulus is 2.0 × 10 ⁴
Highly elastic resin of not less than kg / cm ² and most preferably not less than 2.3 × 10 ⁴ kg / cm ² is mixed.

As the highly elastic resin, for example, polystyrene type or polycarbonate type resin can be used. This high-elasticity resin is mixed in the split resin component, but when this split resin component is the lowest resin component among the resin components constituting the splittable fiber, when this split resin component is fused, In addition, the fusion temperature range is widened, and uniform fusion is possible. Further, when the resin component of the same system is composed of a polyolefin resin component, the polystyrene resin is a polyolefin resin and there is no problem even if it is exposed on the surface of the ultrafine fibers, so that it can be suitably used. The polystyrene-based resin having a syndiotactic structure has a fiber-forming ability, and has a feature that the fiber strength is not lowered even if it is mixed in the divided resin components.

The amount of this highly elastic resin mixed is 0.5 to 49.5.
It is preferably% by volume. If it is less than 0.5% by volume, it is difficult to divide, and if it exceeds 49.5% by volume, the spinnability is deteriorated. Therefore, it is more preferably 4 to 40% by volume.

Although one or more kinds of high-elasticity resins can be used, the linear expansion coefficient of the resin component having the smallest linear expansion coefficient among the resin components to be divided and the high-elasticity resin having the largest linear expansion coefficient is The absolute value of the difference is 2 × 10 ^-5 cm / cm ・
The absolute value of the difference in linear expansion coefficient between the resin component having the largest linear expansion coefficient and the high elastic resin having the smallest linear expansion coefficient is 2 × 1 or more.
When the temperature is 0 ⁻⁵ cm / cm · ° C. or higher, the heat treatment causes distortion due to the difference in thermal expansion between the split resin component containing the high-elasticity resin and the split resin component, which makes it easier to split, and thus a suitable resin is obtained. It is a combination. Examples of the combination of the resins include polystyrene resin as the high elasticity resin, polypropylene as the divided resin component, polycarbonate resin as the high elasticity resin, and polypropylene as the divided resin component.

The splittable fiber of the present invention can be obtained by a conventional composite spinning method. For example, when two kinds of similar resin components are used, it can be obtained by extruding a molten resin obtained by mixing one resin component and a highly elastic resin and the other molten resin, and then compounding them.

The fibrous sheet material of the present invention contains ultrafine fibers obtained by dividing the above-mentioned splittable fibers. The fibrous sheet material may be, for example, a woven fabric, a knitted fabric, a non-woven fabric, or the like, but a non-woven fabric is more suitable because it can impart various characteristics and can be applied to various uses.
The nonwoven fabric will be described below.

First, a fibrous web containing the splittable fiber is formed. The splittable fiber is used in the fiber web in an amount of 5% by weight or more, preferably 30% by weight or more. As a fiber that can be used in addition to the splittable fiber, a fiber composed of a resin component similar to the resin component that constitutes the splittable fiber can be used. In addition, a core-sheath type, a side-by-side type, or an eccentric type composite fiber can also be used, and in this case, the resin component exposed on the fiber surface may be a resin component similar to the splittable fiber.

Examples of the method for forming this fiber web include a dry method such as a card method and an air lay method, a wet method, or a direct method such as a melt blow method and a spunbond method. The fiber web obtained by these methods is used. It may be used alone or in combination. The average fiber length of fibers such as splittable fibers used in the present invention varies depending on the method for forming the fiber web, and is 1 to 25 mm when formed by the wet method.
Is preferably, and when formed by a dry method, it is preferably 20 to 110 mm.

Then, a mechanical flow such as a water stream or a needle punch is applied to the fiber web to divide the splittable fiber. Among these, a water stream that can evenly divide the entire fibrous web without damage to the fibers is preferable. In the splittable fiber of the present invention, the highly elastic resin is mixed in the split resin component and can be split easily by a mechanical external force, so that it becomes easy to obtain a nonwoven fabric containing the same type of ultrafine fiber. When a water flow is applied, for example, the nozzle diameter is 0.05 to 0.3 m
m, preferably 0.08 to 0.2 mm, pitch 0.2 to 3 mm, preferably 0.4 to ² mm, from a nozzle plate arranged in one or more rows, pressure 10 to 300 kg / cm ² , preferably 50 ~ 25
It is sufficient to eject a water flow of 0 kg / cm ² . The action of this water flow is performed once and, if necessary, twice or more. The jet surface of the water stream is one side or both sides of the fiber web.

It should be noted that when a non-opening portion of a support such as a net or a perforated plate on which a fibrous web is placed is thickened when a water flow is applied, a non-woven fabric having a large opening can be obtained. If the non-opened part is thinned, it is possible to obtain a non-woven fabric having no apparent appearance. The former non-woven fabric, for example, consists of a thick wire with a wire diameter of 0.25 mm 60
The latter non-woven fabric can be obtained by using a net having a mesh size of less than mesh and a net having a mesh size of 60 mesh or more, which is made of a thin wire having a wire diameter of 0.25 mm or less.

The splittable fiber of the present invention is easy to split, but among the resin components to be split, the resin component having the smallest linear expansion coefficient and the highly elastic resin having the largest linear expansion coefficient. The absolute value of the difference in the linear expansion coefficient of 2 is 1
0 ^-5 cm / cm · ℃ or higher, or, in the split resin component, a resin component having the largest linear expansion coefficient, the absolute of the difference in linear expansion coefficient between the high elastic resin having a smallest linear expansion coefficient When the splittable fiber having a value of 2 × 10 ⁻⁵ cm / cm · ° C. or higher is used, it is heat treated before applying a mechanical external force to obtain a split resin component containing a highly elastic resin and a split resin component. It is preferable to generate the strain by utilizing the difference in thermal expansion.

In order to make the splittable fiber easier to split, the splittable fiber may be distorted by pressing it with a calender before applying a mechanical external force.

When the splittable fiber is split with a water stream,
In particular, when the fiber length is short and the degree of freedom of the fiber is high, as in the case of a fiber web obtained by the wet method, the splittable fibers easily escape from the water stream even if a water stream is jetted, which makes it difficult to split or causes unevenness. Although it is likely to occur, before jetting the water stream, fusion by the resin component that constitutes the splittable fiber, or, by mixing and fusion the fusion fiber, to reduce the degree of freedom of the splittable fiber,
Since the water flow acts efficiently, it is possible to obtain a non-woven fabric that is easier to divide and has no unevenness. When fusing the resin component constituting the splittable fiber, the melting point difference between the resin component having the lowest melting point and the resin component having the highest melting point among the resin components constituting the splittable fiber is 10 ° C. or more. Using a certain splittable fiber, the degree of freedom of the splittable fiber is lowered, and at least one resin component other than the resin component having the highest melting point is fused under no pressure so as to facilitate splitting. Is preferred.

The fiber sheet material containing ultrafine fibers obtained by dividing the splittable fiber of the present invention is a separator for batteries, filter cloth, interlining, padding, base cloth for patch, mask, medical protection. It can be used for various purposes such as material, base material for synthetic or artificial leather, material for outer garment, interior material, cleaning material, and liquid retaining material. The fibrous sheet material of the present invention may be subjected to post-processing such as hydrophilic treatment or fold processing to suit each application.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0028]

【Example】

(Examples 1 to 4 and Comparative Examples 1 to 3) The split resin and the split resin shown in Table 1 were each melted, extruded at a volume ratio of 1: 1 and then compounded, and then heated in hot water at 95 ° C. Was stretched to 5 times, further heat set in hot water of 95 ° C., and then cut to obtain a splittable fiber having a fineness of 1.3 denier and a fiber length of 10 mm. As shown in FIG. 1, this dividable fiber comprises 16 ultrafine fibers having a circular cross section obtained by dividing a resin component to be divided into eight by a resin component having a fan shape extending radially from the fiber axis to the fiber surface. It could be divided into fibers (fineness 0.08 denier).

Using 100% of this splittable fiber, a fiber web having a basis weight of 60 g / m ² was formed by a wet method, and 135 ° C.
Was heat-treated in an oven to melt the split resin component of the splittable fiber, and then pressure-treated at room temperature with a calender having a linear pressure of 195 kg / cm. Then, the fiber web is treated with a wire diameter of 0.1.
It is placed on a 100-mesh net composed of 4 mm, and a water stream with a pressure of 80 kg / cm ² is ejected from a nozzle arranged with a diameter of 0.13 mm and a pitch of 0.6 mm, then it is reversed and the pressure is 80 kg / cm from the same nozzle. Non-woven fabrics that were treated for 1 cycle, 2 cycles, and 3 cycles were obtained, with the jetting of a water stream of cm ² as one cycle.

(Evaluation of Splittability) Focusing on the fact that if the splittable fibers are divided into ultrafine fibers, the nonwoven fabric structure becomes denser and the air permeability is lowered, and the air permeability of the nonwoven fabric is measured by the following method. It was measured and the splittability was evaluated. The results are shown in Table 1. Using a Frazier type air permeability tester specified in JIS L 1096 6.27 (air permeability test method), a tilting barometer sucks in a pressure resistor to show a pressure of 12.7 mm of water column, and a suction fan The amount of air passing through the nonwoven fabric was determined from the pressure indicated by the vertical barometer and the type of air holes used when the pressure was adjusted.

[0031]

[Table 1]

[0032]

The splittable fiber of the present invention has a flexural modulus of 1.
It is composed of divided resin components in which a high-elasticity resin of 8 × 10 ⁴ kg / cm ² or more is mixed, and divided resin components substantially divided into two or more by this divided resin component, and the divided resin component and the divided resin component are also divided. Since the resin component is a polyolefin resin component, it is a fiber that can be easily divided.

The fibrous sheet material of the present invention is suitable for various uses because it contains ultrafine fibers composed of the same type of resin component obtained by dividing the splittable fiber.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a splittable fiber of the present invention.

FIG. 2 (a) is a schematic sectional view of another splittable fiber of the present invention (b) is a schematic sectional view of another splittable fiber of the present invention (c) is another splittable fiber of the present invention Schematic cross-sectional view (d) Schematic cross-sectional view of another splittable fiber of the present invention

[Explanation of symbols]

1 split resin component 2 Divided resin component ap resin component

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-273654 (JP, A) JP-A-5-321018 (JP, A) JP-A-3-199425 (JP, A) JP-A-5- 33218 (JP, A) JP-A-2-289160 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) D01F 8/00-8/18

Claims (6)

(57) [Claims] 1. A divided resin component in which a highly elastic resin having a flexural modulus of 1.8 × 10 ⁴ kg / cm ² or more is mixed, and a resin component to be divided which is substantially divided into two or more parts by the divided resin component. It becomes, and, dividing the resin component and the object to be split resin component Poriore
A splittable fiber comprising a fin-based resin component. 2. The high elasticity resin is made of polystyrene resin.
The splittable fiber according to claim 1, wherein the resin component to be split comprises polypropylene . 3. The high elasticity resin is a polycarbonate resin
The splittable fiber according to claim 1 , wherein the splittable resin component is polypropylene . 4. The splittable fiber according to claim 1, wherein the high elastic resin is a polystyrene resin. 5. A high elasticity resin is 0.5 in a divided resin component.
˜49.5% by volume mixed together, the splittable fiber according to any one of claims 1 to 4 . 6. A fibrous sheet-like product, comprising ultrafine fibers obtained by dividing the divisible fiber according to any one of claims 1 to 5 .