JPH11152669A - Bulky nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bulky nonwoven fabric that has excellent bulkiness, surface fabric hand and functionality as well as designing capability and its production. SOLUTION: The first fiber layer containing at least 50 wt.% of thermally shrinkable fibers having at least 50% shrinkage with heat at maximum, is laminated on its at least one face with the second fiber layer that substantially does not shrink at the temperature at which the first fiber layer does. A high- pressure fluid is jetted to the laminated fiber layers to interlace with each other. At the same time, the fibers are rearranged to form nonwoven fabric having fine pores opened. Finally the interlaced nonwoven fabric is heat-treated to allow the first fiber layer to shrink to the fiber bundles of the second fiber layer and the curled product having random projections 2 is formed thereby obtaining the objective bulky nonwoven fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-woven fabric having a surface on which a number of curls are formed, comprising a filter,
The present invention relates to a bulky nonwoven fabric that can be effectively used for wipers, towels, wet tissues, packaging materials, hook-and-loop fastener female materials, and the like.

[0002]

2. Description of the Related Art Conventionally, various nonwoven fabrics have been proposed in which two or more fiber layers having different heat shrinkage rates are laminated, and wrinkle-like irregularities are formed on the surface of the nonwoven fabric by utilizing the difference in the heat shrinkage rate of each layer. . For example, JP-A-63-309657 discloses a nonwoven fabric composed of heat-shrinkable fibers and non-shrinkable fibers and integrated by a high-pressure water flow. A wrinkled nonwoven fabric is disclosed. In addition, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 7-54.
In Japanese Patent No. 256, a first fiber layer containing high-shrinkable fibers having a maximum shrinkage rate of at least 50% upon heating and a second fiber layer made of other fibers are integrated by inter-fiber entanglement. Proposal of a bulky nonwoven fabric in which the first fiber layer is shrunk by heat treatment to form a large number of wrinkles on the surface by the second fiber layer, and the apparent thickness is twice or more the thickness of the entangled nonwoven fabric. doing. Furthermore, Japanese Patent Application No. 8-268
No. 951 proposes a nonwoven fabric having a large number of one-way ridge-like convex portions formed substantially parallel to the surface.

[0003]

However, these nonwoven fabrics have the following problems. For example, JP-A-63-
When a nonwoven fabric with fine wrinkles is used as a wiper or a towel as disclosed in JP-A-309657 or JP-A-7-54256, the apparent density is large, so that dust, dirt, dirt, and the like are deposited inside the nonwoven fabric. Cannot be captured, and the amount of capture is limited.

Further, in Japanese Patent Application No. 8-268951, since a long ridge-like convex portion on a straight line is formed by elongation, the degree of freedom of the fiber in the convex portion is higher than the above, and the nonwoven fabric is nonwoven fabric. However, if the long ridge-shaped protrusions are wiped in the vertical direction, the amount of dirt, dust, dirt, and the like trapped extremely decreases.

Furthermore, when these non-woven fabrics are used for a female material of a hook-and-loop fastener, since there are many concave portions and the degree of freedom of the fibers of the convex portions is small, the hook member formed on the male material must be engaged unless strong pressure is applied. Hard to catch on fibers. Therefore, the fact is that a functional nonwoven fabric which has excellent design properties and can be developed for various uses has not yet been obtained. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bulky nonwoven fabric having bulkiness, surface feel, and functionality, and having excellent design properties and a method for producing the same.

[0006]

The bulky nonwoven fabric of the present invention is a nonwoven fabric in which a first fiber layer and a second fiber layer are integrated by entanglement of fibers, wherein the fibers of the second fiber layer are formed of a fiber bundle. Accordingly, the above object was achieved by forming a curl-like material protruding in a random direction. With such a structure of the nonwoven fabric, a bulky nonwoven fabric having excellent design properties having bulkiness, surface feel, and functionality is obtained.

In the bulky nonwoven fabric of the present invention, the thickness of the fiber bundle is preferably 0.2 to 2 mm.

In the bulky nonwoven fabric of the present invention, the first fibrous layer preferably contains at least 50% by weight of heat-shrinkable fibers having a maximum shrinkage by heating of at least 50%.

In the bulky nonwoven fabric of the present invention, the first fiber layer thermally shrinks on at least one surface of the first fiber layer containing at least 50% by weight of heat shrinkable fibers having a maximum shrinkage rate of at least 50% upon heating. After laminating a second fiber layer that does not substantially thermally shrink at a temperature, a high-pressure fluid flow is jetted onto the second fiber layer to entangle the fibers and simultaneously rearrange the fibers to form a nonwoven fabric having apertures formed thereon. By performing the treatment, the first fiber layer is thermally contracted, the fibers of the second fiber layer are formed into a fiber bundle, and the curl-like material protruding in a random direction can be formed. Hereinafter, the contents of the present invention will be specifically described.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The bulky nonwoven fabric according to the present invention is a nonwoven fabric in which a first fiber layer and a second fiber layer are integrated by entanglement of fibers, wherein the fibers of the second fiber layer are not a fiber bundle. A curl-like material that is raised in random directions. FIG. 1 is a perspective view of one embodiment of the present invention as viewed from a second fiber layer side. The fibers constituting the second fiber layer are entangled to form a fiber bundle, and each fiber bundle forms a raised curl in a state of winding in a random direction. Therefore, it has a structure in which many small spaces having different sizes and depths are formed. The design is clearly different from the conventional nonwoven fabric in which a long ridge-shaped space is formed by forming a large number of wrinkles that are irregularly densely formed as a conventional short ridge as shown in FIG. .

The fibers used in the first fiber layer of the present invention are not particularly limited as long as the fibers have a potential heat shrinking property. Fibers with potential heat shrink performance include, for example, polyester / copolyester, polypropylene / ethylene-propylene copolymer,
Apparently heat-shrinkable side-by-side composite fiber or eccentric core-sheath composite fiber composed of a combination of polypropylene / ethylene-butene-propylene terpolymer, or copolyester, ethylene-propylene copolymer, ethylene-butene-propylene Latent heat-shrinkable fibers composed of a terpolymer are exemplified.

In particular, the first fiber layer preferably contains at least 50% by weight of a heat-shrinkable fiber having a maximum shrinkage rate of at least 50% upon heating. More preferably, the heat shrinkable fiber has a maximum heat shrinkage of at least 80% at least 70% by weight. Here, the maximum shrinkage refers to the highest shrinkage in the shrunk state of the heated fiber while maintaining the fiber shape. When the shrinkage rate of the heat-shrinkable fiber is less than 50%, the shrinkage is insufficient and the state becomes close to that of an ordinary nonwoven fabric, and a bulky nonwoven fabric in which a fiber bundle forms a curled material protruding in random directions is obtained. Can not. Further, even if the shrinkable fiber has a shrinkage of about 80%, if it is mixed with 50% or more of other ordinary fibers, a bulky nonwoven fabric having a desired curled material cannot be obtained.

The heat-shrinkable fibers satisfying the above conditions include, for example, fibers made of a polymer containing at least 70% by weight of an ethylene-propylene random copolymer (EP) having a melting peak temperature (Tm ° C.) of 130 <Tm <145. It is suitable. The above-mentioned melting peak temperature refers to the temperature at which a DSC curve at the time of performing differential calorimetry (DSC) of a polymer shows a maximum value. If the melting peak temperature is lower than 130 ° C., the polymer will exhibit rubbery elasticity, and the fiber will have poor card permeability. Conversely, if it exceeds 145 ° C,
It is not preferable because the heat shrinkage of the fiber is about the same as ordinary polypropylene. When the proportion of the ethylene-propylene random copolymer is less than 70% by weight, the maximum heat shrinkage of the obtained fiber is less than 50%, which is not preferable. As the polymer to be mixed with the ethylene-propylene random copolymer, it is preferable to use an ethylene-propylene-butene-1 terpolymer or a polyolefin-based polymer such as polypropylene.

The mode of the first fiber layer may be any of a parallel web made of staple fibers, a cross web, a semi-random web, a random web, etc., but it is better to concentrate the heat shrinkage of the fiber layer in one direction. In the second fiber layer, curls protruding in random directions are more easily formed. Therefore, it is desirable that the first fiber layer is a parallel web. The first fiber layer may be laminated with the second fiber layer as it is as a web, or may be a nonwoven fabric in which fibers are lightly entangled or bonded in advance.

Next, the second fiber layer will be described. Second
The fibrous layer forms a curled material that protrudes in many random directions due to the heat shrinkage of the first fibrous layer. Accordingly, the material constituting the second fiber layer is not particularly limited as long as it can form a fiber aggregate and does not substantially shrink at a temperature at which the first fiber layer shrinks. For example, recycled fibers such as rayon, semi-synthetic fibers such as acetate, polyamide fibers such as nylon 6, nylon 66, polyethylene fibers such as polyethylene terephthalate and polybutylene terephthalate, polyethylene,
One or two or more selected from polyolefin fibers such as polypropylene can be used. More preferably, when a high-pressure fluid flow described later is injected, a material having good fiber entanglement is preferably used, and rayon fiber is particularly preferable. Also, the fiber shape and the like are not particularly limited,
A splittable conjugate fiber, a fiber having an irregular cross section, or the like can be arbitrarily used.

For example, when the finally obtained nonwoven fabric is used as a wet wiper, the second fiber layer is preferably composed mainly of hydrophilic fibers such as rayon fibers. Also,
When used as a precision wiper or a wiper for cleaning intended to wipe off fine dust, etc., a synthetic fiber having a fineness of 3 denier or less, or a splittable composite fiber or polyester comprising a combination of nylon / polyester, polyester / polypropylene. It is preferable that the second fiber layer is mainly composed of the system fiber. Further, in order to improve the wear resistance of the finally obtained nonwoven fabric, it is advisable to mix fibers which can be melted at a temperature at which the heat-shrinkable fibers in the first fiber layer thermally shrink into the second fiber layer.

The form of the second fiber layer is not particularly limited, and examples thereof include a parallel web or cross web made of staple fibers, a semi-random web, a long fiber web made of continuous filaments, a web made of short fibers by wet papermaking, and a melt blown nonwoven fabric. Can be used arbitrarily. In order to strengthen entanglement with the first fiber layer, it is desirable to use a web made of staple fibers. The second fiber layer may be laminated with the first fiber layer as it is as a web, or may be a nonwoven fabric in which fibers are lightly entangled or bonded in advance.

Then, the first fiber layer and the second fiber layer are laminated. In both fiber layers, it is preferable to laminate the first fiber layer / second fiber layer so that the basis weight ratio is 1/5 to 3/1. More preferably, it is 1/3 to 2/1. If the basis weight ratio of the first fiber layer / the second fiber layer exceeds 1/5, the second fiber layer becomes difficult to follow the heat shrinkage stress of the first fiber layer.
It becomes difficult to form curls protruding in random directions. If the basis weight is less than 3/1, the flexibility of the entire nonwoven fabric is impaired, which is not preferable. Also, the second
The fiber layers can be laminated on one or both sides of the first fiber layer.

The obtained laminate is jetted with a high-pressure fluid flow to entangle the fibers and simultaneously rearrange the fibers to form a nonwoven fabric having openings. "Fluid" used in the present invention
Is not limited as long as the fibers can be entangled with each other and the fibers can be rearranged. However, water is particularly desirable in terms of process control. Injection of the high pressure fluid stream is performed under conditions such that the fibers of the web are rearranged to form apertures in the nonwoven. Specifically, the web is placed on a support for forming holes, and a high-pressure fluid stream is jetted onto the web. The form of the support for forming the openings is not particularly limited, and a commonly used one such as a pattern net formed by weaving a monofilament or a metal wire or a roll provided with protrusions can be used arbitrarily.

The injection of the high-pressure fluid stream may be performed only on the support for forming the aperture. Alternatively, after preliminarily entangled with a low-pressure fluid flow, the fluid flow may be jetted on the support for forming the holes. Preliminary entanglement increases the strength of the resulting nonwoven. It is necessary to set the pressure of the fluid flow to be sprayed on the support for forming the openings in accordance with the basis weight of the web to be processed and the presence or absence of pre-entanglement. For example, 20-100g /
When processing of the m ² web, the pressure of the fluid flow 30 to 10
It is preferably 0 kg / cm ² . If it is less than 30kg / cm ^2,
It is difficult to form holes due to insufficient energy of the fluid flow. If it exceeds 100 kg / cm ² , the fibers may be scattered to deteriorate the formation, and the support may be damaged depending on the material and shape of the support. When carrying out preliminary confounding, the web is placed on a permeable support and 20 to 60
A fluid flow of kg / cm ² may be injected.

The shape of the opening is not particularly limited, and may be a circle, an ellipse, a diamond, a square, or the like. A staggered shape, a lattice shape, or the like is used for the opening pattern, but a staggered shape is more preferable. The resulting opening has a hole diameter of 0.5 mm to 3.0 mm,
The interval between the non-opening portions made of fiber bundles may be 3.0 mm or less. When the pore diameter exceeds 3.0 mm, the nonwoven fabric becomes bulky and slightly perforated, and it is difficult to form a curled material. 0.5mm
If it is less than 3, the pores disappear after the heat treatment. When the interval between the non-opening portions formed of the fiber bundles exceeds 3.0 mm, it becomes a conventional short ridge shape and becomes close to a wrinkle shape that is irregularly dense.

The obtained nonwoven fabric having pores is subjected to a heat treatment, and the first fiber layer is shrunk to form a curl-like material protruding in a random direction on the second fiber layer. The heat treatment is performed at a temperature at which the heat-shrinkable fibers in the first fiber layer shrink. In the bulky nonwoven fabric of the present invention, the treatment is performed under the condition that the area shrinkage of the first fiber layer is 15 to 85%, that is, the condition that the area after the heat treatment is 15 to 85% before the heat treatment. Is preferred. More preferred area shrinkage is 40 to 8
0%. If the area shrinkage exceeds 85%, curls formed of fiber bundles will be in a dense state, and an appropriate space cannot be obtained. If the area shrinkage is less than 15%, the desired curled product cannot be obtained.

The size of the non-perforated portion made of the fiber bundle in the obtained perforated nonwoven fabric affects the thickness of the fiber bundle forming the curl after the heat treatment. The thickness of the fiber bundle forming a curled material raised in random directions,
0.2 to 2 mm is preferred. More preferably, 0.5 to 1.
2 mm. When the thickness of the fiber bundle exceeds 2 mm,
As with the conventional wrinkled nonwoven fabric, the space formed by the curled loop becomes smaller, and when used for a wiper, for example, the amount of dirt, dust, or dirt trapped decreases. When the thickness of the fiber bundle is less than 0.2 mm, the strength of the fiber bundle is weakened. For example, when the fiber bundle is used for a wiper or the like, fuzzing occurs due to friction with a wiping surface, or fibers are torn and dust is generated. I do.

As described above, the nonwoven fabric having a curl-like material protruding in a random direction by the heat treatment is the same as the conventional nonwoven fabric having a short ridge and a large number of wrinkles that are irregularly densely formed. Are obviously different in design. Since the bulky nonwoven fabric of the present invention does not have a long groove-shaped space unlike the conventional multi-wrinkled nonwoven fabric, the nonwoven fabric surface has little resistance and can be used in various applications. For example, when used for a wiper, the slipperiness on the target surface is good, and the sliding friction resistance is particularly preferably 200 g or less. More preferably, it is 100 to 150 g. When the sliding friction resistance exceeds 200 g, the weight is felt at the time of wiping, and discomfort is given. Also, when used as a wipe for personal use, such as a wet tissue or a towel, the touch is smooth and the touch is excellent. Alternatively, in the case of using the hook-and-loop fastener for a female material, the male hook member is deeply inserted into fine spaces having different sizes and depths, and is firmly engaged with the curled portion of the female material.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described with reference to embodiments. The thickness, tensile strength, elongation at break, sliding friction resistance, and wiping performance of the obtained nonwoven fabric were measured as follows. (Thickness) The thickness was measured using a thickness measuring machine (trade name: THICKNESS GAUGE model CR-60A, manufactured by Daiei Kagaku Seiki Seisaku-sho, Ltd.) with a load of 20 g applied per 1 cm ^{2 of} the sample.

(Tensile strength, breaking elongation) JIS L 1
According to No. 096, a sample piece having a width of 5 cm and a length of 15 cm was gripped at an interval of 10 cm, and stretched at a tensile speed of 30 cm / min using a constant-speed stretching type tensile tester. Tensile strength and breaking elongation were used.

(Sliding friction resistance) A cleaning tool for flooring manufactured by Kao Corporation (wiping area: 10 cm × 26 cm, pattern length: 34 cm, weight: 235 g) is placed on the wiping surface, and a spring is placed at the top of the pattern. The hook was pulled and the spring was pulled along the handle while the handle was fixed at an angle of 45 degrees, and the load when the cleaning tool started to move was defined as the sliding friction resistance.

(Wiping performance) Collection rate: Spread 0.5 g of bread crumbs uniformly on a glass surface, attach a nonwoven fabric whose weight has been measured in advance to the cleaning tool, and place a load of 500 g on the wiping surface. After moving a distance of 60 cm and making one reciprocation, the weight of the nonwoven fabric was measured, and the difference in weight before and after wiping was defined as the collected amount (g). The collection amount / 0.5 was defined as the collection rate (%). Retention rate: The cleaning tool collected above was dropped five times from a height of about 10 cm, and the weight difference between the weight of the nonwoven fabric after falling five times and the weight of the nonwoven fabric before wiping was defined as the retention amount. And the retention amount / collection amount was defined as the retention ratio.

(Example 1) As the first fiber layer, a heat-shrinkable fiber having a fineness of 2 denier and a fiber length of 51 mm and a maximum heat shrinkage of 92% was formed from an ethylene-propylene random copolymer having a melting peak temperature of 136 ° C. Using a semi-random card machine (manufactured by Daiwa Spinning Co., Ltd.), a card web having a basis weight of 10 g / m ² was produced.

As the second fiber layer, a fineness of 1.5 denier,
Using a semi-random card machine, a rayon fiber having a fiber length of 40 mm (manufactured by Daiwabo Rayon Co., Ltd.) was used.
to produce a carded web m ^2, laminated on the first fibrous layer,
It was a laminated web.

The above-mentioned laminated web was subjected to a columnar water flow of 30 kg / cm ^{2 with} a water pressure of 30 kg / cm ² with the first fiber layer on the surface side using a nozzle provided with orifices having a hole diameter of 0.1 mm at intervals of 0.6 mm.
At the same time, a columnar water stream having a water pressure of 20 kg / cm ² was sprayed twice on the back side to produce an entangled nonwoven fabric in which the constituent fibers of the web were entangled.

Then, the entangled nonwoven fabric was placed on a support for forming pores (plain woven fabric manufactured by Nippon Filcon Co., Ltd., 25 mesh) such that the first fiber layer was on the nozzle surface, and the water pressure was 30 kg / water. A columnar water flow of 2 cm ² was sprayed twice, subjected to a hole opening treatment, and dried at 90 ° C. to obtain an open non-woven fabric.

The open nonwoven fabric is subjected to a heat shrinkage treatment at 135 ° C. using a hot air penetration type processing machine to shrink the heat shrinkable fibers, whereby the fibers of the second fiber layer are turned into fiber bundles in random directions. With a curl-like material protruding on the surface 1
A bulky nonwoven fabric of 20 g / m ² was obtained.

(Example 2) As the second fiber layer, fineness of 1.
70% by weight of polyethylene terephthalate fiber (manufactured by Teijin Limited) with 5 denier and 51 mm fiber length and 30% by weight of rayon fiber (manufactured by Daiwa Bow Rayon Co., Ltd.) with 1.5 denier and 40 mm fiber length In the same manner as in Example 1, a bulky nonwoven fabric having a basis weight of 115 g / m ² was obtained.

(Comparative Example 1) The laminated web used in Example 1 was subjected to a water pressure of 30 kg / h with the first fiber layer on the surface side using nozzles having orifices with a hole diameter of 0.1 mm provided at 0.6 mm intervals. 2 times columnar water flow of cm ² , water pressure 20kg / c on the back side
The columnar water stream of m ² by spraying twice to prepare a entangled nonwoven fabric made of entangled web of constituent fibers. And one entangled nonwoven fabric
A heat shrink treatment was performed at 30 ° C. to shrink the heat shrinkable fibers to form a nonwoven fabric having a basis weight of 95 g / m ² .

(Comparative Example 2) The basis weight was calculated in the same manner as in Comparative Example 1 except that the entangled nonwoven fabric was subjected to a heat shrink treatment at 135 ° C.
A g / m ² nonwoven fabric was obtained.

Table 1 shows the physical properties of the nonwoven fabrics of Examples 1 and 2 and Comparative Examples 1 and 2.

[0038]

[Table 1]

In Examples 1 and 2, the fibers of the second fiber layer are formed into fiber bundles to form curls protruding in random directions. Had been formed. Then, despite the small irregularities on the surface of the nonwoven fabric, the loop of the curl-like material retained the space, had good slipperiness on the target surface, and was excellent in wiping performance. Furthermore, the touch was smooth.

On the other hand, in Comparative Examples 1 and 2, a large number of wrinkles were formed in a short ridge shape and irregularly densely formed, and Comparative Example 2 formed finer wrinkles.
In each of these, a long groove-like space was formed on the surface of the nonwoven fabric, and the unevenness was large, and sufficient slipperiness with respect to the target surface was not obtained.

[0041]

The bulky nonwoven fabric of the present invention has a structure in which the fibers are formed into a fiber bundle to form a curl-like material protruding in a random direction, and have a conventional short ridge shape and irregularly densely packed. A nonwoven fabric having a large number of wrinkles is obviously different in design. And not only the design, but also on the functional surface, despite the small unevenness on the surface of the nonwoven fabric, the loop of the curled material holds the space, so it is only excellent in the slipperiness of the nonwoven fabric surface However, it is suitable for supporting different kinds of substances. The bulky nonwoven fabric of the present invention can be effectively used for filters, wipers, towels, wet tissues, packaging materials, hook-and-loop fastener female materials, and the like.

[Brief description of the drawings]

FIG. 1 is an example of a bulky nonwoven fabric of the present invention.

FIG. 2 shows a conventional bulky nonwoven fabric.

[Explanation of symbols]

 1. 1. Bulk nonwoven fabric Curled objects raised in random directions

Claims (4)

[Claims] 1. A non-woven fabric in which a first fiber layer and a second fiber layer are integrated by entanglement of the fibers, wherein the fibers of the second fiber layer form fiber bundles and are curled up in random directions. The bulky nonwoven fabric characterized by forming. 2. The bulky nonwoven fabric according to claim 1, wherein the thickness of the fiber bundle is 0.2 to 2 mm. 3. The heat-shrinkable fiber, wherein the first fiber layer has a maximum shrinkage rate by heating of at least 50%.
The bulky nonwoven fabric according to claim 1 or 2, wherein the bulky nonwoven fabric is contained. 4. A maximum shrinkage rate by heating is at least 50.
% Of at least one side of the first fiber layer containing at least 50% by weight of the heat-shrinkable fiber, a second fiber layer that does not substantially heat-shrink at a temperature at which the first fiber layer heat-shrinks is laminated.
A high-pressure fluid flow is jetted onto the fibers to simultaneously entangle the fibers, and at the same time rearrange the fibers to form a nonwoven fabric having apertures formed thereon. A method for producing a bulky nonwoven fabric, comprising forming fibers of two fiber layers into a fiber bundle and forming a curled material protruding in random directions.