JPH11131347A - Nonwoven fabric made of ultra fine filament having crease on its surface, its production and nonwoven fabric product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nonwoven fabric wiper that can pick up fine dust and the like between creases by forming relatively large creases on the surface of nonwoven fabric sheet made of melt-blown ultra fine fibers. SOLUTION: A fiber-forming thermoplastic resin as polypropylene is melt- extruded extruded from the spinneret orifices, drawn with hot air into a fiber flow and a part of the flow is received via a roller receiver tentatively and allowed to flow down as the receiver rotates or by the self-weight of the staying fibers. In the meantime, the rest part of the fiber flow is directly piled up on the fiber-collecting and sheet-forming machine to form web. Then, the resultant web is intermittently hot-jointed via the thermal embossing roll its surface to the base sheet face and the creases thereon thereby forming the objective nonwoven fabric sheet made of ultra fine fibers of 0.1-10 μm fiber diameter having randomly wavy creases that extend in the widthwise direction and has a size of 1-10 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a microfiber nonwoven fabric,
More particularly, the present invention relates to a melt blown nonwoven fabric having a fold extending relatively long in the surface width direction, a method for efficiently producing the nonwoven fabric, and the nonwoven fabric product.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. Hei 8-3850 discloses a method in which a first fiber layer containing a heat-shrinkable fiber and a heat-adhesive fiber and a second fiber layer made of a non-shrinkable fiber are laminated and intermittently interposed. It is disclosed that the first fiber layer is contracted by heat-bonding and then heated to form folds (irregularities) in the second fiber layer made of non-shrinkable fibers. However, this method requires the use of a fiber layer containing a heat-shrinkable fiber and a heat-adhesive fiber as the fiber material, which requires relatively high cost for the production means and relatively low product cost. It is not suitable for wiper applications such as cleaning products, for example, cleaning sheets for removing dust.

[0003] Japanese Patent Publication No. 7-37703 discloses that a stretchable sheet is stretched, laminated with a non-stretchable sheet capable of forming a gather, and both are laminated by hot embossing. Immediately after releasing the stretched state,
A stretch sheet which shrinks to form gathers on a non-stretch sheet and a method for producing the same are disclosed. However, this is indispensable to use a stretchable nonwoven fabric made of an elastic elastomer in order to form a gather, and is a composite laminate, and has the same disadvantages as those of the above-mentioned known examples.

Further, Japanese Patent Publication No. 26152212 discloses that a melt blown nonwoven fabric having a surface irregularity is formed by spraying a blown fiber onto an irregular shaped collecting and forming surface when forming a melt blown nonwoven fabric. The production method is disclosed. The melt-blown nonwoven fabric obtained by this manufacturing method is different from the above-described known example in which the melt-blown nonwoven fabric has a multilayer structure, and is capable of forming unevenness with the melt-blown nonwoven fabric alone. Is difficult, and the production cost is extremely high in that a trapping net having an uneven shape must be used, and its maintenance is not easy.

[0005] As described above, melt blown
Although nonwoven fabrics are already known, they must be laminated with other nonwoven fabric materials, and even melt-blown nonwoven fabrics having irregularities alone cannot form large fold-like irregularities due to their production. In addition, the manufacturing means requires special means, which is not preferable in terms of manufacturing cost.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a melt-blown nonwoven fabric which solves the above-mentioned disadvantages and a method for producing the same which is easy and inexpensive. That is, the present invention provides a nonwoven fabric consisting of a single layer of a melt-blown nonwoven fabric having relatively large random folds on its surface, and in particular, a microfiber nonwoven fabric consisting of a single layer, in which the size and spacing of the folds are random. More specifically, for example, a wiper for cleaning (this is a method in which small dust is taken into the surface of the non-woven fabric like a normal melt blown non-woven fabric, and even larger dust is removed by a fold formed on the surface. An effect of increasing the wiping effect is required by taking in the inside, but an object which can exhibit the effect of (2) is not provided. Another object of the present invention is to provide a method for easily and efficiently producing a single-layer ultrafine nonwoven fabric having a single layer, in which the sizes and intervals of the folds are random.

[0007]

That is, the first aspect of the present invention is a nonwoven fabric made of ultrafine fibers having an average fiber diameter of 0.1 μm to 10 μm, wherein the nonwoven fabric has random folds. The random fold is a microfiber nonwoven fabric characterized by being a wavy fold derived from the sheet surface serving as the nonwoven fabric base, extending mainly in the width direction, and mainly fluttering in the length direction. .

A second aspect of the present invention is the ultrafine fiber nonwoven fabric according to the first aspect, wherein the size of the random fold is 1 mm to 10 mm from the sheet surface serving as the nonwoven fabric substrate. is there.

The third aspect of the present invention is directed to the ultrafine fiber nonwoven fabric according to the first or second aspect,
This is a microfiber nonwoven fabric in which the folds are intermittently bonded to the sheet surface serving as the nonwoven fabric substrate by thermal bonding.

[0010] The fourth invention of the present invention is to produce a microfiber nonwoven fabric by a melt-blowing method, which is derived from the sheet surface of the microfiber web, mainly extends in its width direction, and mainly flows in its length direction. A method for producing a microfiber nonwoven fabric having a wavy random fold, comprising: receiving a fiber stream at a drop point of the fiber stream below a spinning nozzle, temporarily suspending the fiber stream, and then dropping the fiber stream downward. The fiber body spun from the spinning nozzle is placed on the temporary receiver, and the fiber stream is dropped downward by the rotation of the receiver or / and the weight of the staying fiber stream to be collected and collected on a collection molding machine. A method for producing a microfiber nonwoven fabric.

According to a fifth aspect of the present invention, there is provided the method for producing a microfiber nonwoven fabric according to the fourth aspect of the present invention, wherein the web collected on the collecting and forming machine is thermally bonded by a hot embossing roll. And a method for producing a microfiber nonwoven fabric, characterized by intermittently thermally bonding a substrate sheet surface and a fold thereon.

[0012] In a sixth aspect of the present invention, there is provided the method for producing a microfiber nonwoven fabric according to the fourth or fifth aspect, wherein the temporary receiver is a roll. It is a manufacturing method of.

[0013] The seventh aspect of the present invention is a nonwoven fabric wiper made of ultrafine fibers having an average fiber diameter of 0.1 µm to 10 µm, wherein the nonwoven fabric has random folds, When the microfiber nonwoven fabric, which is a wavy fold derived from the sheet surface serving as the nonwoven fabric substrate, extends mainly in the width direction, and mainly flutters in the length direction, is formed on at least one surface, and is wiped off. Is a microfiber non-woven fabric wiper characterized in that dust is taken into the fold.

According to an eighth aspect of the present invention, there is provided the ultrafine fiber nonwoven fabric wiper according to the seventh aspect, wherein the fold is intermittently bonded to a sheet surface serving as a nonwoven fabric substrate by thermal bonding. This is a microfiber nonwoven wiper.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A method for producing a microfiber nonwoven fabric having a fold on its surface according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing the production process of the ultrafine fiber nonwoven fabric of the present invention, in which a fiber-forming thermoplastic resin is heated and melted to a predetermined temperature by an extruder (1), and a fiber flow (3) from a spinning nozzle (2).
As the nozzle (2)
The following describes a so-called melt-blowing production process in which the fiber stream (3) is blown and drawn by heated air jetted from the left and right sides, and the fiber stream (3) is collected on a collection molding conveyor (4) to produce a nonwoven fabric.

In such a production method, the production method of the present invention is such that after a part of the fiber stream (3) blown off by hot air is once received on a receiver (5) such as a roll, the receiver (5) ) Is dropped onto the collecting and forming conveyor (4) by the rotation of ()). As a result, in the present invention, a normal melt blown web is formed on the collecting and forming conveyor (4), and the web surface is extended (continuously) mainly in the width direction thereof, and mainly flutters in the length direction thereof. The resulting wavy, irregularly sized folds (6) will result. FIG. 2 is a perspective plan photograph instead of a drawing showing a plane of the present microfine nonwoven fabric (7) having the folds (6) formed therein. This is the length direction (the direction of flow of the nonwoven fabric in the manufacturing process). FIG. 3 is a cross-sectional view showing a cut end face obtained by cutting the microfiber nonwoven fabric (7) in its thickness direction along its length direction. As shown in this figure, the folds (6) are not uniform in size and size and their waving state, but in any case, they extend mainly in the width direction of the nonwoven fabric and mainly in the wavy state thereof. The irregular wavy folds (6) thus formed are countlessly formed on the entire surface of the nonwoven fabric. The formed folds (6) have a density of formation, depending on the speed difference between the falling speed of the fiber stream (3) received on the receiver (5) from the receiver and the moving speed of the collecting conveyor, The size and the like are determined, and more specifically, it is affected by the size of the roll of the receiver (5) and the like, the installation position of the receiver, and the like.

The fiber-forming thermoplastic resin in the present invention includes, for example, polyethylene, ethylene-propylene copolymers, ethylene-butylene copolymers, ethylene-octene copolymers and other ethylene-based polymers, polypropylene and propylene copolymers. Polymers, polyolefins such as polybutylene, 6-nylon, 66-nylon, 6.66-
Copolyamide, 610-nylon 11-nylon,
Polyamide such as 12-nylon or copolyamide, polyester such as polyethylene terephthalate, ethylene terephthalate copolymer, polybutylene terephthalate, aliphatic polycarbonate, polyurethane elastomer, polyester It is at least one polymer selected from elastomer, polyvinyl chloride or copolymer, wholly aromatic polyester, polyphenylene sulfide, and the like.

In particular, in the present invention, polypropylene is preferably used because the raw materials are easily available and inexpensive, and the production of the melt-blown nonwoven fabric itself is easy.

An important point in the present invention is that melt blow
Immediately before collecting some or all of the fiber stream on the molding conveyor (4), the fiber stream is temporarily received and retained on the receiver (5),
After that, it is dropped on the collecting and forming conveyor (4), whereby a fold (6) extending relatively long in the width direction is formed on the web surface. As understood by this method, the present manufacturing method is easy to manufacture itself and is extremely useful industrially.

The receiving body (5) is preferably a rotating body such as a roller as described above, but may be a plate-shaped body instead of the roller. In short, the spun fiber stream (3) is temporarily Fiber stream (3)
May be sequentially dropped from the receiver (5) due to the inclination of the receiver (5) and the weight of the fiber stream.

When the receiving body (5) is a rotating body such as a roller, the receiving body (5) may be eccentric, and an elliptic cylindrical shape or a star-shaped cylindrical shape may be preferably used. It is not limited to this.

When the receiving body (5) is a rotating body, it is preferably a free roll, but it can be driven if necessary.

The receiver (5) can be installed anywhere between the blow spinning nozzle (1) and the collecting and conveyer (4), but in the vicinity of the blow spinning nozzle (1),
The fiber stream (3) blown by the heat of the hot air may adhere to the receiver (5) in a molten state, so that it is better not to approach them too much.

It is important to cool the blown fibers to prevent the fiber stream from fusing to the receiver (5) when collected on the receiver (5). The technique for cooling the fiber stream coming out of the nozzle is a technique already known in US Pat. No. 3,949,29 and the like.

If the fold (6) to be formed is too large, the fold is torn due to friction and catch with the contact surface during use, leading to the entire breakage. Preferably, the length is 1 to 10 mm. When the size is small, the folds are mainly raised on the melt-blown nonwoven base sheet, and when the size is large, the folds (6) are, as shown in FIG. Above,
It is mainly formed in a state in which the sheet is folded down in the length direction of the sheet. If the size of the folds (6) is smaller than 1 mm, the gap between the folds and the folds intended in the present invention is not sufficient, which is not preferable. Cannot be used effectively, and is liable to be damaged, which is not preferable.

Folds of the melt-blown nonwoven fabric of the present invention (6)
Are bonded to the base sheet by the usual nonwoven fabric manufacturing process, but the folds (6) are easily deformed or torn even in contact with an object or even contact with friction. It is important that nothing happens. Therefore, it is desirable that the fold (6) be fixed more firmly on the base sheet. The method of fixing is not particularly limited, but heat embossing, ultrasonic fusion and the like are effective,
In particular, the hot embossing bonding comprising a convex embossing roll and a flat roll is more preferable in terms of easy operation.

It is important that the fixing of the folds (6) is not very tight. If the fixing is performed at a higher density than necessary, the folds (6) are all crushed, and the intended purpose of the present invention for retaining dirt or the like between the folds cannot be achieved.

Therefore, for example, when a hot embossing roll is used, a strip-shaped embossing roll extending in the rotation direction is used to fix the fold (6), and a partial heat-sealed portion extending in the length direction of the nonwoven fabric is used. It is good to do by making. In this case, the stripe does not necessarily have to be straight, but may be bent or meandering. Further, it is preferable that the thickness of the stripe or the width of the stripe-shaped projections of the embossing roll is about 0.1 to 2 mm, and the pitch between the projections is about 10 to 50 mm. Alternatively, the stripe does not necessarily have to be a continuous line, but may be a dotted line. By doing so, the folds can be partially fixed without crushing the folds on the surface.

Since the wiper using the melt-blown nonwoven fabric (7) of the present invention has a pocket composed of folds (6) on its surface, small trash can be removed between the single fiber entanglement of the nonwoven fabric during wiping. The trapped and large debris can be trapped in the pocket consisting of the folds (6) and the large and small debris can be wiped off with a single wiper without using multiple wipers. When the melt-blown nonwoven fabric (7) of the present invention is used as a face towel, its texture such as touch to the skin is extremely preferable due to its fine fiber structure and irregular folds (6) on the surface. Yes, this can be used not only for face towels, but also as other direct skin contact clothing and medical materials.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a wiper will be described in more detail with reference to the embodiments. However, the present invention is not limited to this embodiment.

In this example, the melt flow rate of polypropylene was measured by the method described in ASTM-D1238 (L).

The tensile strength of the non-woven fabric was measured by using an Autograph AGS-50D manufactured by Shimadzu Corporation according to JIS-L-10.
According to the strip method described in No. 96, the measurement was carried out under the conditions of a width of 5 cm, a grip interval of 10 cm, and a tensile speed of 10 cm / min.
Furthermore, the tensile elongation of the nonwoven fabric was determined by the same method as that at the maximum tensile strength.

The wiping property as a wiper was evaluated by the following evaluation test. (1) Dust removal rate and dirt degree: Using a cotton grind type antifouling tester, the test piece was mounted so that the 4 × 4 cm wide surface was exposed, and 50 g of clean dry sand and standard test dust (JIS)
Z8901 test dust) 1g, 60rpm
The specimen is contaminated at a speed of m. The percentage of the increased weight of the sample relative to the weight of the standard test dust input is the dust removal rate. The lightness difference between before and after the contamination of this sample is the contamination degree. This lightness was measured using a Nippon Denshoku Colorimeter. (2) Hair wiping test: Hair substitute 10 on test surface
The book is scattered, the test piece is attached to a wiping tool of "Quickle" manufactured by Kao Corporation, and the number of hair substitutes removed when the test surface is wiped is taken as the test result.

Example 1 A polypropylene having a melt flow rate of 700 was melt-extruded by an extruder and melt-spun at a spinning temperature of 275 ° C. and a single hole discharge rate of 0.23 g / min.
It was pulled by heated air of 4 kg / cm ² . This fiber flow
A part thereof is received on a stainless steel free roll provided at a position 20 cm below the spinning die, and a melt-blown nonwoven fabric layer (base layer) is collected and formed on a wire mesh conveyor 10 cm below the same while the above-mentioned stagnation is maintained. The fibers are dropped, and the two are fused and joined in the preheated state, and the average basis weight is 50 g / m ↑ 2.
Of polypropylene melt blown ultrafine fiber nonwoven fabric. The tensile strength of this nonwoven fabric is 1.6 kg in the MD direction.
/ 5 cm, 1.9 kg / 5 cm in the CD direction, and the elongation was 15% in the MD direction and 68% in the CD direction.

The shape of the melt blown nonwoven fabric is shown in FIG.
As shown in the photograph of the surface of the nonwoven fabric, the irregular folds (6) formed on the surface mainly in the width direction of the nonwoven fabric (CD direction) and formed at appropriate intervals in the length direction of the nonwoven fabric (MD direction) Was formed. The shape of the cut end of the nonwoven fabric cut in the thickness direction was such that the folds (6) fluttered in the MD direction of the nonwoven fabric or extended in a prone state as shown in the schematic diagram of FIG.

As an example of the use of this nonwoven fabric, a cotton wool antifouling test and a hair wiping test were performed to evaluate the action as a flooring wiper. The hair wiping test was performed using a desk surface and a tatami mat surface as test surfaces. In addition, as a comparative example, a conventional melt blown spinning was performed without installing a receiver for temporarily retaining the fiber stream under the spinning nozzle in the above-described production method (that is, the surface was smooth without folds). The same nonwoven fabric as that of the above example was used.
Table 1 shows the results.

[0037]

[Table 1]

As shown in Table 1, the ultrafine nonwoven fabric having a fold on its surface according to the present invention can significantly improve the dust removal rate at the time of wiping and the wiping property of the hair as compared with the nonwoven fabric having no fold.

[0039]

The microfiber nonwoven fabric of the present invention has a fine gap structure composed of microfibers, including its main body and folds, and a unique fold-fold fold structure on its surface. When it is used as a wiping cloth, the former structure allows fine dust to be easily captured, and at the same time, the latter structure allows relatively large dust such as hair to be captured between the fold spaces. It can exhibit extremely excellent effects as a tool. In addition, the method for producing the nonwoven fabric of the present invention can be carried out by simply adding a rotating body without requiring any special equipment, and it is extremely easy to carry out the method and is an industrially superior method. It is clear from the above description that the melt blown nonwoven fabric of the present invention is not limited to a wiper.

[Brief description of the drawings]

FIG. 1 is a process conceptual diagram outlining a method for producing a microfiber nonwoven fabric of the present invention.

FIG. 2 is a perspective plan photograph instead of a drawing showing the surface of the ultrafine fiber nonwoven fabric of the present invention.

FIG. 3 is a schematic cross-sectional view of the microfiber nonwoven fabric of the present invention cut in the thickness direction and in the length direction.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 extruder 2 spinning nozzle 3 fiber flow 4 collecting and forming conveyor 5 receiver (roll) 6 fold 7 ultrafine nonwoven fabric of the present invention

Claims (8)

[Claims] 1. A non-woven fabric comprising ultrafine fibers having an average fiber diameter of 0.1 μm to 10 μm, wherein the non-woven fabric has random folds, and the random folds are derived from a sheet surface serving as a non-woven fabric substrate. An ultrafine fiber nonwoven fabric, characterized by being wavy folds mainly extending in the width direction and waving mainly in the length direction. 2. The ultrafine fiber nonwoven fabric according to claim 1, wherein the size of the random fold is 1 mm to 10 mm from the sheet surface serving as the nonwoven fabric substrate. 3. The ultrafine fiber nonwoven fabric according to claim 1, wherein the folds are intermittently bonded to a sheet surface serving as a nonwoven fabric substrate by thermal bonding. 4. A microfiber nonwoven fabric is produced by a melt-blowing method, and is derived from a sheet surface of the microfiber web.
A method for producing a microfiber nonwoven fabric which has a wavy random fold extending mainly in its width direction and mainly waving in its length direction, the method comprising the steps of: A temporary receiver for receiving and temporarily holding the stream and then dropping downward is installed, receives the fiber stream spun from the spinning nozzle on the temporary receiver, rotates the receiver, and / or own weight of the staying fiber stream A fine fiber non-woven fabric, wherein the non-woven fabric is collected on a collecting and forming machine to form a non-woven fabric. 5. The ultrafine fiber according to claim 4, wherein the web collected on the collecting and forming machine is thermally bonded by a hot embossing roll to intermittently heat-bond the base sheet surface and the fold thereon. Manufacturing method of nonwoven fabric. 6. The method according to claim 4, wherein the temporary receiver is a roll. 7. A nonwoven fabric wiper comprising ultrafine fibers having an average fiber diameter of 0.1 μm to 10 μm, wherein the nonwoven fabric has random folds, and the random folds are derived from a sheet surface serving as a nonwoven fabric substrate. A microfiber nonwoven fabric, which is a wavy fold mainly extending in the width direction and mainly waving in the length direction, is provided on at least one side, and dust when wiped is taken in the fold. A microfiber non-woven fabric wiper characterized in that: 8. The ultrafine nonwoven fabric wiper according to claim 7, wherein the folds are intermittently bonded to the sheet surface serving as the nonwoven fabric substrate by thermal bonding.