JPH08269855A - Stretchable nonwoven fabric and its production - Google Patents

Abstract

PURPOSE: To provide a stretchable nonwoven fabric having excellent stretch recovery and to provide its production process. CONSTITUTION: This stretchable nonwoven fabric has a structure containing entangled fiber bundles containing crimped fibers. The fiber bundles are present in the fabric in a nearly crossed state and are entangled with each other also at the crossing point of the bundles. The nonwoven fabric exhibits a stretch recovery of >=50% in at least one direction. The fabric is produced by placing a fiber web containing latent crimping fibers on a supporting member having a mesh size finer than 40 mesh, treating the fibers with water jet ejected under an ejection pressure of >=35kg/cm<2> to entangle the fibers, placing the treated fabric on a supporting member having a mesh size not finer than 40 mesh, treating the fibers with water jet ejected under an ejection pressure of >=50kg/cm<2> to effect the entangling of the fibers and the forming of openings and developing the crimp of the latent crimping fibers by heat-treatment.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a stretchable nonwoven fabric and a method for producing the same.

[0002]

2. Description of the Related Art Stretchable nonwoven fabrics are suitable for use as, for example, a base fabric for external medicines because they easily fit the body. This stretchable nonwoven fabric can be obtained, for example, by entanglement of a fiber web containing latently crimpable fibers with a needle or a water stream, and then by heat treatment to develop crimps of the latently crimpable fibers. However, since such a stretchable non-woven fabric has a low elongation recovery rate, it has a poor fit property with respect to a portion such as an elbow or a knee that requires a large elongation.

[0003]

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 stretchable nonwoven fabric having an excellent elongation recovery rate and a method for producing the same.

[0004]

The stretchable nonwoven fabric of the present invention has a structure in which entangled fiber bundles containing crimped fibers substantially intersect each other and are entangled at the intersections of the entangled fiber bundles. The extension recovery rate in one direction is 50% or more.

According to the method for producing a stretchable nonwoven fabric of the present invention, a fiber web containing latently crimpable fibers is placed on a support having a finer mesh than 40 mesh, and a jet pressure of 35 kg / cm ² or more is applied. Entangled and then placed on a 40 mesh or a coarser mesh than 40 mesh, with a jet pressure of 50 kg / c
After forming an opening at the same time as entangled with a water flow of m ² or more,
This is a method of developing crimp of the latent crimpable fiber by heat treatment.

[0006]

The elastic nonwoven fabric of the present invention will be described based on the manufacturing method. First, a fibrous web containing latently crimpable fibers is formed. The latent crimpable fiber is a fiber web made of 100% of one kind of fiber, which is moved at a speed of 5 m / min or more while having a nozzle hole diameter of 0.1 to 0.3 mm and a hole interval of 0.1 mm.
5 to 15 mm, pressure less than 200 kg / cm ² water flow 1-2 times,
A fiber having an area shrinkage of 10% or more when heat-treated at a temperature lower than the melting point of the fiber after being spouted to form an entangled fiber web.
Composed of a combination of resins such as polyester, copolymer polypropylene / polypropylene, polypropylene / polyamide, polyethylene / polypropylene, polypropylene / polyester, polyethylene / polyester,
The composite fibers having a fiber cross-sectional shape such as an eccentric shape or a bonded shape can be used alone or in combination. Among these,
A laminated composite fiber made of a combination of copolymerized polyester / polyester or copolymerized polypropylene / polypropylene is excellent in crimp expression and thus can be preferably used. The latent crimpable fiber is preferably contained in an amount of 30% by weight or more, more preferably 50% by weight or more.

Fibers other than the latently crimpable fiber may be appropriately mixed depending on the intended use of the stretchable nonwoven fabric. For example, recycled fiber such as rayon fiber, semi-synthetic fiber such as acetate fiber, polyamide fiber, vinylon fiber and the like. , Vinylidene fiber, polyvinyl chloride fiber, polyester fiber, acrylic fiber, polyethylene fiber, polypropylene fiber,
Synthetic fibers such as polyurethane fibers, plant fibers such as cotton,
Animal fibers such as wool can be used. For example, when a stretchable nonwoven fabric is used as a base fabric for external medicine, polyester fibers or polypropylene fibers having excellent chemical resistance can be preferably used.

The fineness of the fibers used in the stretchable nonwoven fabric of the present invention is preferably 0.5 to 5 denier and the fiber length is preferably 20 to 110 mm.

After forming a fiber web containing such latently crimpable fibers, it is entangled with a water stream. The fiber web can be formed by either a dry method such as a card method or an air lay method, or a wet method. However, in order to improve the balance between the strength of the stretchable nonwoven fabric in the warp direction and the transverse direction, a parallel web in which the fibers are oriented in one direction with a card machine, etc. It is preferable to form the cross-laid web by orienting so as to intersect with. When stacking parallel webs, it is preferable that the weight of the parallel webs is not more than a quarter of the weight of the entire fibrous web so that the difference in strength between the warp direction and the weft direction does not become large. Further, the fiber web may be appropriately laminated depending on the application such as laminating the fiber web obtained by the dry method and the fiber web obtained by the wet method, or laminating the fiber webs having different fiber compositions.

Then, the fiber web is entangled with a water stream. This entanglement method is carried out by first using a support body (hereinafter referred to as a "first support body") on which the fiber web is first placed. Use a mesh finer than the mesh and jet pressure of 35kg / cm ² or more (hereinafter referred to as "first jet pressure")
After applying the water flow of 40 mesh, it is placed on a 40 mesh or a support having meshes coarser than 40 mesh (hereinafter, referred to as “second support”), and a jet pressure of 50 kg / cm ² or more (hereinafter, referred to as “second support”).
A jet of water (referred to as “jet pressure”) acts to entangle and simultaneously form an opening.

The conditions of the first support and the first ejection pressure are necessary to improve the elongation recovery rate by entanglement of the entire fiber web. If a coarser mesh than 40 mesh is used as the first support, not only the entire fiber web cannot be entangled, but also the fibers fall out from the support, causing unevenness in the fiber web. Uses a finer mesh than 40 mesh. More preferably, a finer support than 50 mesh is used. Moreover, the first ejection pressure is 35 kg / cm ²
If it is lower than this, the degree of entanglement is low and the elongation recovery rate is not improved. Therefore, the first ejection pressure is set to 35 kg / cm ² or more, and more preferably 40 kg / cm ² or more.

Next, the conditions of the second support and the second ejection pressure are conditions necessary for further entanglement of the fibrous web which has been entangled to some extent, and at the same time, to form the aperture. By forming the opening portion in this manner, the opening portion is easily deformed and thus has excellent extensibility. Further, the entangled fiber bundles surrounding the opening portion are entangled at the intersections, and the opening shape can be maintained. Therefore, it is also excellent in elongation recovery. Therefore, the second support is 40 mesh or one having a coarser mesh than 40 mesh, and more preferably 30 mesh, so that the openings can be easily formed.
Use a coarser mesh than the mesh. Further, the second ejection pressure is set to 50 kg / cm ² or more so that the openings can be formed and the entanglement can be performed at a high degree. More preferably, the second ejection pressure is 60 kg / cm ² or more.

The entanglement treatment by the water flow on the first and second supports may be performed once or, if necessary, twice or more. At least one injection pressure is set to 35 kg / cm ² or more, and at least one injection pressure is set to 50 kg / cm ² or more.
The surface treated by the water flow on the second support is the first
It is preferable that the surface of the support is opposite to the surface treated with the water flow to suppress fiber fluffing.

The other water flow conditions may be the same as the conventional ones, specifically, the diameter is 0.05 to 0.3 mm and the pitch is 0.2.
A ~ 3 mm nozzle plate may be used.

Next, the entangled fiber web is heat-treated to develop the crimp of the latent crimpable fiber to obtain a stretchable nonwoven fabric. By this crimp expression, the entangled fiber web shrinks,
Although it may appear as a stretchable non-woven fabric having no openings, the fibers are not entangled due to the occurrence of crimp, and therefore the stretchability is not impaired. On the other hand, it is preferable that 3 to 22% of the surface of the elastic nonwoven fabric is the open portion, and 5 to 20% is the open portion because the one having the open portion is more excellent in stretchability. It is more preferable. When the stretchable nonwoven fabric is used as a base fabric for an external medicine, the opening portion is 10 times so that the medicine does not seep out to the back surface.
% Or less is preferable.

Further, when the fibers are adhered to each other by this heat treatment, the stretchability is deteriorated. Therefore, in order to prevent the fibers from adhering to each other, the temperature is lower than the lowest melting point of the fibers constituting the fiber web, preferably 10 ° C. or more. It is preferable to heat-treat at a temperature. Further, it is preferable that the heat treatment is performed under no tension except for the tension in the warp direction produced during production so that the development of the crimp of the latent crimp fiber is not hindered. In addition, the crimped fiber in the present invention means a fiber in which the crimp of the latent crimpable fiber is developed.

The elastic nonwoven fabric thus obtained is
The entangled fiber bundle formed by the water flow on the second support substantially intersects with each other, and has a structure in which the entangled fiber bundles are also entangled with each other, and the elongation recovery rate in at least one direction is 50%.
The above-mentioned elongation recovery is excellent. Further, since this stretchable nonwoven fabric is highly entangled by the action of water flow on the first support and the second support, the result of the abrasion resistance test is grade 3 or higher, more preferably 4 or higher. Above grade,
It has excellent wear resistance.

This elongation recovery rate is based on JIS L 1096.
^-1990 (General textile test method) A value measured according to the method for measuring elongation recovery ratio specified in 6.14.2. The sample gripping interval was 10 cm. Also, abrasion resistance is JI
S-L-1076, evaluation by the method specified in the A method.

Further, the tensile strength of the stretchable nonwoven fabric of the present invention is preferably 4 kg / 5 cm width or more, more preferably 5 kg / 5 cm width or more in both the vertical direction and the horizontal direction. Although the basis weight varies depending on the use, 50 to 200 g / m ² is preferable from the viewpoint of entanglement due to water flow and crimping of the latent crimpable fiber. For example, when used as a base fabric for an external medicine,
70 to 120 g / m ² is preferable.

The stretchable nonwoven fabric of the present invention may be combined with a woven fabric, a knitted fabric, a net or the like, but care must be taken not to impair the stretchability.

As described above, since the stretchable nonwoven fabric of the present invention is excellent in stretchability, it is used as a base material for external medicine, a base material for cuffs, simple clothing, a cover material, a packaging material, a base material for synthetic leather, and a core material. It can be suitably used as a base material for molding cotton, a mask, a ceiling material for automobiles, or the like.

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

[0023]

【Example】

(Examples 1 to 7, Comparative Examples 1 to 4) having a cross-sectional shape in which a copolyester (melting point: 230 ° C.) and polyester are laminated, a fineness of 2 denier, a fiber length of 50 mm, and an area shrinkage ratio (cross-laid web Nozzle hole diameter 0.15 mm, hole spacing 1.0 m while moving at a speed of 30 m / min or more
100% of latent crimpable composite fiber (Kuraray Co., Ltd., Sofit) having 40% of entangled fiber web obtained by jetting a water flow of m and a pressure of 120 kg / cm ² twice was opened by a card machine. The parallel web was crossed with a cross layer in the flow direction of the conveyor to form a cross-laid web. After this crosslaid web was placed on the first and second supports shown in Table 1, the diameter was 0.15 mm and the hole spacing was 0.6.
The water flow was jetted from the nozzle plate of mm at the first and second jet pressures shown in Table 1 to entangle the crosslaid web. The surface on which the water stream was ejected on the second support was the surface opposite to the surface on which the water stream was ejected on the first support. Then, the entangled cross-laid web is dried at 150 ° C. without tension, and at the same time, crimping of the latently crimpable conjugate fiber is developed to give a basis weight of 85.
A stretchable nonwoven fabric of g / m ² was obtained. The physical properties of the elastic nonwoven fabric were as shown in Table 1.

[0024]

[Table 1]

(Tensile Strength) Examples 1 to 7 and Comparative Examples 1 to 1
The tensile strength of the stretchable non-woven fabric of No. 4 was measured by Tensilon (manufactured by Orientec Corporation, UCT-500) at a width of 50 mm, a gripping length of 200 mm and a pulling speed of 200 mm / min. In addition, this measurement was performed for each of the five stretchable nonwoven fabrics in the vertical direction and the horizontal direction, and the average value thereof was taken as the tensile strength. The results are also shown in Table 1.

[0026]

INDUSTRIAL APPLICABILITY The stretchable nonwoven fabric of the present invention has a structure in which entangled fiber bundles containing crimped fibers are substantially intersected with each other, and entangled fiber bundles are also entangled at the intersections thereof, and elongation recovery in at least one direction is achieved. It has an elongation recovery of 50% or more.

In the method for producing a stretchable nonwoven fabric of the present invention, a fibrous web containing latently crimpable fibers is placed on a support having a finer mesh than 40 mesh, and a jet pressure of 35 kg / cm ² or more is applied to the web. Entangled and then placed on a 40 mesh or a coarser mesh than 40 mesh, with a jet pressure of 50 kg / c
After forming an opening at the same time as entangled with a water flow of m ² or more,
This is a method of causing the latent crimpable fiber to be crimped by heat treatment, and a stretchable nonwoven fabric excellent in elongation recovery can be easily obtained.

Claims (2)

[Claims] 1. A structure in which entangled fiber bundles containing crimped fibers substantially intersect each other and entangled at intersections of the entangled fiber bundles, and an elongation recovery rate in at least one direction is 50% or more. A stretchable non-woven fabric characterized by the above. 2. A fiber web containing latently crimpable fibers, 4
Placed on a support having a mesh finer than 0 mesh, entangled with a water jet having a jet pressure of 35 kg / cm ² or more, and then placed on 40 mesh or a support having a mesh coarser than 40 mesh,
A method for producing a stretchable non-woven fabric, characterized in that the latent crimpable fiber is crimped by heat treatment after forming an opening at the same time as entanglement with a water flow having a jet pressure of 50 kg / cm ² or more.