JP7260081B2 - LAMINATED NONWOVEN FABRIC AND MANUFACTURING METHOD THEREOF, AND WIPER - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to laminated nonwoven fabrics and methods of making same, and wipers comprising such laminated nonwoven fabrics.

One use of nonwoven fabrics is wipers for wiping dirt from a person's body or objects. There are many different wiper configurations. For example, Patent Document 1 discloses a fiber structure having an ultrafine fiber layer containing ultrafine fibers containing a modified vinyl alcohol resin and a plurality of types of ultrafine fibers containing other resins, which are produced by splitting splittable conjugate fibers. A wiping sheet containing an object has been proposed. Further, in Patent Document 2, thin fibers with a fiber diameter of 0.1 μm or more and 9 μm or less and thick fibers with a fiber diameter of 10 μm or more and 30 μm or less are used, and the proportion of the thin fibers present is higher than that on the first surface. A wet wiping sheet has been proposed in which the proportion of high, coarse fibers present is higher on the second side opposite the first side.

Japanese Patent Application Laid-Open No. 2006-000625 WO2018/105340

To provide a nonwoven fabric which solves problems caused when a fiber layer containing ultrafine fibers forms the surface of the nonwoven fabric, while taking advantage of ultrafine fibers. Specifically, the present invention provides a nonwoven fabric that can provide a wiper that is resistant to clogging due to clogging due to kinks caused by the ultrafine fiber layer and dust even when the ultrafine fibers are positioned on the wiping surface.

In the first gist, this embodiment is a laminated nonwoven fabric comprising an ultrafine fiber layer containing ultrafine fibers with a fiber diameter of 0.01 μm to 10 μm and a base fiber layer,
The ultrafine fiber layer and the base fiber layer are integrated by entangling the fibers,
The ultrafine fiber layer is partially broken to form a plurality of streaks along one direction of the nonwoven fabric,
The average width of one line of the ultrafine fiber layer in a direction orthogonal to one direction of the nonwoven fabric is 0.1 mm to 0.5 mm,
The average spacing between adjacent microfiber layers is 0.7 mm to 1.2 mm,
A laminated nonwoven fabric is provided.

In the second gist of the present embodiment, a first hydroentangling step of hydroentangling a substrate fiber web;
After the first hydroentanglement treatment step, a lamination step of laminating an ultrafine fiber web containing ultrafine fibers with a fiber diameter of 0.01 μm to 10 μm on the base fiber web to form a laminated fiber web;
a second hydroentangling treatment step of hydroentangling from the surface of the ultrafine fiber web of the laminated fiber web;
After the second hydroentangling treatment step, a widening step of laterally widening the laminated fiber web by a factor of 1.05 to 1.50 to partially break the ultrafine fiber web;
A method for producing a laminated nonwoven fabric is provided, comprising a third hydroentangling treatment step of subjecting the laminated fiber web to a hydroentangling treatment after the widening step.

This embodiment provides, in a third aspect, a wiper comprising the laminated nonwoven fabric according to the first aspect.

In the laminated nonwoven fabric of this embodiment, the ultrafine fiber layer is partially broken to form a plurality of streaks along one direction of the nonwoven fabric. Problems when the fibers are located on the surface of the nonwoven fabric can be eliminated. Therefore, when this is used as a wiper, it is less likely to be twisted, and while ensuring good wiping performance due to the ultrafine fibers, more dust can be collected and clogging is less likely to occur.

It is the front view and partial enlarged view which show an example of the widening apparatus used by a widening process. 1 is a micrograph of the laminated nonwoven fabric (after dyeing) obtained in Example 1. FIG. 2 is a micrograph of the laminated nonwoven fabric (after dyeing) obtained in Comparative Example 1. FIG.

(Circumstances leading to this embodiment)
The present inventors attempted to reduce the fiber diameter of the ultrafine fibers in order to obtain a wiper with better wiping performance. When trying to obtain ultrafine fibers using splittable conjugate fibers, in order to reduce the fiber diameter of the fibers after splitting, the fineness of the fibers before splitting is decreased or the number of splits (number of sections) is increased. There is a need. However, when a web is produced by carding using splittable conjugate fibers having a reduced fineness, cardability is deteriorated, making it difficult to obtain a uniform nonwoven fabric. In addition to the fact that the fiber itself is thin, the reason for the deterioration of the card passability is that the fiber splits during passage through the card. Moreover, if the number of splits is increased, the production of the splittable conjugate fiber itself becomes difficult.

Therefore, the present inventors have investigated using a melt-blown nonwoven fabric as the ultrafine fiber layer instead of using splittable conjugate fibers. Melt-blown non-woven fabrics are manufactured by blowing out a thermoplastic resin melted in an extruder from a die with a high-temperature, high-speed air flow to form fibers, which are then accumulated on a conveyor (melt-blowing method). . Therefore, the meltblown nonwoven fabric can be produced from fibers having an extremely fine fiber diameter.

The present inventors prepared a laminated nonwoven fabric by integrating this meltblown nonwoven fabric with other fiber base materials, and investigated using this as a wiper. However, if the wiping operation is performed with the meltblown nonwoven fabric side as the wiping surface, the friction is large and it is difficult to lightly wipe off, and the nonwoven fabric is twisted as a whole, making it difficult to continue the wiping operation. I know it will happen.

Therefore, the present inventors have investigated a configuration that can prevent the occurrence of twisting and clogging while maintaining the excellent wiping properties of the ultrafine fibers that constitute the meltblown nonwoven fabric. As a result, a wiper that avoids these problems by mechanically expanding (i.e. widening) the transverse dimension of the integrated laminated fibrous web after integrating the meltblown nonwoven fabric with the fibrous layer serving as the base material. was able to obtain Specifically, by breaking the meltblown nonwoven fabric by mechanically expanding the width, a structure in which a plurality of streaks derived from the meltblown nonwoven fabric are formed at intervals is obtained, and the streaks ensure good wiping performance. , a wiper capable of collecting dust between streaks was obtained. In addition, since the part where the ultrafine fibers are aggregated exists as a plurality of streaks, the occurrence of twisting is also suppressed.
The laminated nonwoven fabric of this embodiment will be described below.

(ultrafine fiber layer)
The laminated nonwoven fabric of this embodiment includes an ultrafine fiber layer containing ultrafine fibers having a fiber diameter of 0.01 μm to 10 μm, and a base fiber layer. First, the ultrafine fiber layer will be explained.
The microfibers contained in the microfiber layer have a fiber diameter of 0.01 μm to 10 μm. When the fiber diameter of the ultrafine fibers is within this range, good wiping properties are exhibited when the surface of the ultrafine fiber layer is used as a wiping surface. The fiber diameter of the microfibers may in particular be between 0.1 μm and 8 μm, more in particular between 0.5 μm and 5 μm, even more in particular between 1 μm and 3 μm. It is difficult to obtain ultrafine fibers with a fiber diameter of less than 0.01 μm, for example by meltblowing or other methods, and it is difficult to improve wiping properties when using fibers with a fiber diameter of more than 10 μm.

The ultrafine fibers are preferably synthetic fibers made of synthetic resin. If the ultrafine fibers are synthetic fibers, wiping may become easier when the wiping surface of the liquid-impregnated wiping material is the surface of the ultrafine fiber layer. Specific examples of ultrafine fibers include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and copolymers thereof; polypropylene, polyethylene (high (including high-density polyethylene, low-density polyethylene, linear low-density polyethylene, etc.), polybutene-1, propylene-based propylene copolymers (propylene-ethylene copolymers, propylene-butene-1-ethylene copolymers including), ethylene-vinyl alcohol copolymer, and ethylene-polyolefin resins such as vinyl acetate copolymers; polyamide resins such as nylon 6, nylon 12 and nylon 66; acrylic resins; polycarbonate, polyacetal, polystyrene and engineering plastics such as cyclic polyolefins, and one or more thermoplastic resins arbitrarily selected from elastomers thereof.

The synthetic resin that constitutes the ultrafine fibers may be, in particular, a homopolymer polyolefin resin, more particularly polypropylene, polymethylpentene, or polyethylene. These resins are hydrophobic, and when the surface of the ultrafine fiber layer is used as a wiping surface, they may improve the wiping ability of oil-based stains. In the case of impregnation, when the aqueous solution is released from the fractured portion of the ultrafine fiber layer, the aqueous solution is not absorbed into the ultrafine fiber layer, so the sustained release property can be well controlled.

In this embodiment, the ultrafine fibers may be those formed by a meltblowing method. In the melt blowing method, as described above, the thermoplastic resin melted in the extruder is blown out from the die with a high-temperature, high-speed air flow to form fibers, which are then accumulated on a conveyor to produce fibers and non-woven fabrics. It is a method of manufacturing simultaneously. According to this method, it is possible to obtain ultrafine fibers having the above-described fiber diameters with less variation in fiber diameters.

In the present embodiment, the ultrafine fibers may be obtained by a method other than the meltblowing method as long as they have the above fiber diameter. For example, it may be obtained by a method of dissolving/removing the sea component of the sea-island composite fiber, or may be obtained by an electrospinning method.

Ultrafine fibers obtained by a meltblowing method or an electrospinning method do not have a constant fiber diameter depending on manufacturing conditions, and ultrafine fibers having different fiber diameters may be contained in the ultrafine fiber layer. In that case, each ultrafine fiber should have a fiber diameter within the above range or an average fiber diameter within the above range. The average fiber diameter is obtained by using an electron microscope to observe the surface of the nonwoven fabric, for example, magnifying it 100 to 1000 times, measuring the width of the side surface of any 100 fibers, and calculating the average value of the measured values. can ask. When a plurality of fibers are fused and their boundaries are unknown, the fiber group in the fused state is regarded as one fiber and measured.

The ultrafine fiber layer may contain, for example, 50% by mass or more, particularly 60% by mass or more, and more particularly 70% by mass or more of ultrafine fibers having the above fiber diameter. The microfiber layer may contain only microfibers. When the ultrafine fiber layer contains fibers other than ultrafine fibers, that is, fibers with a fiber diameter of more than 10 μm, if the ratio of the other fibers is too high, it may not be possible to obtain good wiping properties due to the ultrafine fibers. . Moreover, even when the other fibers are included, the fiber diameter is preferably as small as possible, for example, the fiber diameter does not exceed 20 μm. In addition, the ultrafine fiber layer containing the other fibers corresponds to one having an average fiber diameter exceeding 10 μm, and in such an ultrafine fiber layer, the ratio of the ultrafine fibers is such that the fiber diameter is 10 μm. It is assumed that the ratio occupied by the following fibers.

In the nonwoven fabric of this embodiment, the ultrafine fiber layer is partially broken to form a plurality of streaks along one direction of the nonwoven fabric. In order to achieve this configuration, the ultrafine fiber layer may have a basis weight of 5 g/m ² to 30 g/m ² before being integrated with the base fiber layer (or base fiber web) described later. , from 6 g/m ² to 25 g/m ² , more particularly from 7 g/m ² to 20 g/m ² . If the basis weight is too small, the number of ultrafine fibers in the streaks formed by partial breakage will also decrease, making it difficult to obtain good wiping properties. If the basis weight is too large, partial breakage will occur. It can be difficult to bring about.

A plurality of streaks formed by breaking the microfiber layer extend along one direction of the nonwoven fabric, particularly along the machine direction (also referred to as machine direction or MD direction) of the nonwoven fabric. Streaks extending in the longitudinal direction of the nonwoven fabric are relatively easily and continuously formed by the manufacturing method described below. Each of the plurality of striations may have an average width of 0.1 mm to 0.5 mm in a direction perpendicular to said one direction of the nonwoven. If the stripes extend along the machine direction of the nonwoven, the average width of the stripes is the dimension of the stripes in the cross direction of the nonwoven.

As will be described later, the average width of the streaks is obtained by dyeing the laminated nonwoven fabric with a dye that does not dye the ultrafine fiber layer but dyes the base fiber layer, and the dyed laminated nonwoven fabric after dyeing. It is obtained by measuring the width of the non-existent part (that is, the streak) at a plurality of points and calculating the average value. To determine the average width, three widths are determined for each muscle over a length range of about 2.0 mm for at least 14 muscles. Therefore, the average width is calculated from at least 42 measurements. Dyeing may be performed with a dye that dyes only the microfiber layer and does not dye the base fiber layer. In this case, the width of the dyed portion is measured.

The average width of the stripes may in particular be between 0.2 mm and 0.5 mm, more particularly between 0.3 mm and 0.4 mm. If the average width of the streaks is too small, the wiping performance of the ultrafine fibers may not be sufficiently improved. be.

In this embodiment, the average spacing between adjacent microfiber layers may be 0.7 mm to 1.2 mm. The spacing between adjacent streaks corresponds to the distance between streaks in a direction parallel to the width of the streak and corresponds to the width of the portion substantially free of microfibers. As will be described later, the average interval between adjacent streaks is obtained by dyeing the laminated nonwoven fabric with a dye that does not dye the ultrafine fiber layer but dyes the base fiber layer, and the dyed portion (streak It is obtained by measuring the width of the part between the line and the line) at multiple points and calculating the average value. To determine the average spacing, the width of three dyed sections over a length range of about 2.0 mm is determined for at least seven dyed sections. Therefore, the average interval is calculated from at least 21 measurements. Dyeing may be performed with a dye that dyes only the ultrafine fiber layer and does not dye the base fiber layer, in which case the width of the undyed portion is measured.

The average spacing of adjacent striations may in particular be between 0.8 mm and 1.2 mm, more particularly between 0.9 mm and 1.1 mm. If the average interval is too small, the ability of the nonwoven fabric to collect the wiped dust may decrease. After wiping off, the distance to wipe off the dust with the next streak is long, and the wiping performance of the entire nonwoven fabric may decrease.

In this embodiment, the average width of the plurality of stripes formed by breaking the ultrafine fiber layer may be 0.25 mm or more smaller than the average interval between adjacent stripes of the microfiber layer. In this case, it may be more effective in solving the problem when the ultrafine fibers are positioned on the surface of the nonwoven fabric, while taking advantage of the advantages of the ultrafine fibers. The average width of the plurality of stripes formed by breaking the ultrafine fiber layer is more preferably 0.30 mm or more, more preferably 0.35 mm or more, smaller than the average interval between adjacent stripes of the microfiber layer. In this embodiment, the average width of the plurality of stripes formed by breaking the ultrafine fiber layer may be 1.0 mm or less smaller than the average interval between adjacent stripes of the ultrafine fiber layer. The benefits it provides may be better played. The average width of the plurality of stripes formed by breaking the ultrafine fiber layer is more preferably 0.9 mm or less, more preferably 0.8 mm or less, than the average interval between adjacent stripes of the microfiber layer.

In addition, on the surface of the nonwoven fabric, the area ratio of the ultrafine fiber layer may be 5% to 30%. The area ratio of the ultrafine fiber layer refers to the ratio of the ultrafine fiber layer to the surface of the nonwoven fabric. As will be described later, the area ratio of the ultrafine fiber layer is obtained by dyeing the laminated nonwoven fabric with a dye that does not dye the ultrafine fiber layer but dyes the base fiber layer, and in the laminated nonwoven fabric after dyeing, the undyed portion is The occupied ratio is determined by measuring at a plurality of locations and calculating the average value. In determining the area ratio, the ratio of the unstained portion is determined for at least 10 areas in an area of about 0.6 mm x about 1.8 mm. Therefore, the area ratio of the ultrafine fiber layer is calculated from at least 10 measurements. Dyeing may be performed with a dye that dyes only the ultrafine fiber layer and does not dye the base fiber layer. In this case, the proportion of the dyed portion is measured.

The area percentage of the microfiber layer may in particular be between 8% and 25%, more particularly between 10% and 20%. If the area ratio of the ultrafine fiber layer is too small, the improvement in wiping performance due to the ultrafine fibers may not be sufficiently obtained. may occur and wiping cannot be continued.

(Base fiber layer)
Next, the base fiber layer will be described. The base fiber layer supports the microfiber layer and provides a surface to be touched by a user or attached to a jig during a wiping operation. Also, when the laminated nonwoven fabric is used as a wet wiper, it becomes a portion that retains liquid.

The base fiber layer may be made of any fiber depending on how the wiper is used. Examples of fibers constituting the base fiber layer are as follows.
Natural fibers such as pulp, cotton, hemp, silk, and wool;
regenerated fibers such as viscose rayon, cupra, and solvent-spun cellulose fibers (e.g., lenting glyocell® and tencel®);
Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and their copolymers; (including high-density polyethylene, etc.), polybutene-1, propylene-based propylene copolymers (including propylene-ethylene copolymers and propylene-butene-1-ethylene copolymers), ethylene-vinyl alcohol copolymers , and polyolefin resins such as ethylene-vinyl acetate copolymer; polyamide resins such as nylon 6, nylon 12 and nylon 66; acrylic resins; engineering plastics such as polycarbonate, polyacetal, polystyrene and cyclic polyolefins, and their A synthetic fiber made of one or more thermoplastic resins optionally selected from the elastomers of

When the substrate fiber layer comprises synthetic fibers, the synthetic fibers may be single fibers consisting of a single component (also referred to as "single section") and/or may be composed of multiple components (also referred to as "sections"). It may be a composite fiber composed of. The conjugate fiber may be, for example, a concentric or eccentric core-sheath conjugate fiber, a sea-island conjugate fiber, a side-by-side conjugate fiber, or a split conjugate fiber. The cross-section of the fibers may be circular or non-circular, with non-circular shapes including elliptical, Y-shaped, X-shaped, I-shaped, multi-lobed, polygonal, star-shaped, and the like. The synthetic fibers may also have a hollow cross-section. In both the single fiber and the composite fiber, each section constituting the fiber may consist of one type of resin, or two or more types of resin may be mixed.

When the synthetic fiber is a single fiber, the single fiber is made of one or more resins selected from the group consisting of the polyolefin resins, the polyester resins, the polyamide resins, and the acrylic resins. can be More specifically, polypropylene monofilaments, polyethylene terephthalate monofilaments, and the like may be used.

When the synthetic fiber is a conjugate fiber, the conjugate fiber is, for example, a combination of a polyester resin and a polyolefin resin such as polyethylene terephthalate/polyethylene, polyethylene terephthalate/polypropylene, and polyethylene terephthalate/propylene copolymer, and polypropylene. A combination of two types of polyolefin-based thermoplastic resins such as /polyethylene and polypropylene/propylene copolymer, and a combination of two types of polyester-based resins. Here, polyethylene may be, for example, high density polyethylene, low density polyethylene, or linear low density polyethylene, or a mixture of two or more polyethylenes selected from these.

The thermoplastic resin exemplified as the component of the single fiber or the composite fiber may contain other components as long as it contains 50% by mass or more of the specifically indicated thermoplastic resin. The specifically indicated thermoplastic resin may be contained in an amount of 80% by mass or more, or may be contained in an amount of 90% by mass or more, or the constituent component is substantially composed of the specifically indicated thermoplastic resin. good. Here, the term "substantially" is used in consideration of the fact that thermoplastic resins usually contain various additives and the like. For example, in the combination of polyethylene/polyethylene terephthalate, "polyethylene" may contain other thermoplastic resins and additives as long as it contains 50% by mass or more of polyethylene. This also applies in the following examples.

When the laminated nonwoven fabric of the present embodiment is used as a wet wiper that contains a liquid, the base fiber layer preferably contains hydrophilic fibers. This is for holding the liquid in the base fiber layer. Hydrophilic fibers, for example, regenerated fibers such as viscose rayon, cupra, and solvent-spun cellulose fibers (e.g., lenting glyocell® and tencel®), as well as pulp, cotton, hemp, silk, and wool. and other natural fibers.

When the substrate fiber layer contains hydrophilic fibers, the lower limit of the ratio may be, for example, 5% by mass, particularly 7% by mass, when the mass of the entire substrate fiber layer is 100% by mass. and more particularly 10% by weight. Moreover, the upper limit of the mixing ratio of the hydrophilic fibers may be, for example, 80% by mass, particularly 40% by mass, and more particularly 20% by mass. If the proportion of hydrophilic fibers is too small, the laminated nonwoven fabric may not be able to retain a sufficient amount of liquid. It may become difficult to release.

When hydrophilic fibers are included in the base fiber layer, synthetic fibers may be included as fibers other than the hydrophilic fibers. The synthetic fibers serve to release the liquid retained in the base fiber layer from the wiping surface of the wiper onto the object. Synthetic fibers may include, for example, polyethylene terephthalate monofilament, polypropylene monofilament, polyethylene monofilament.

The fineness of the fibers constituting the base fiber layer is not particularly limited as long as the base fiber layer supports the ultrafine fiber layer and imparts strength to the entire laminated nonwoven fabric to withstand use as a wiper. The fineness of the fibers constituting the base fiber layer may be, for example, 1.0 dtex or more and 4.0 dtex or less, particularly 1.1 dtex or more and 3.0 dtex or less, and more particularly 1.2 dtex or more and 2.0 dtex or less. It may be 0 dtex or less. If the fineness of the fibers constituting the base fiber layer is too small, the laminated nonwoven fabric may not have sufficient strength, and the base fiber layer will be dense, reducing the amount of liquid that can be retained. Sometimes. If the fineness of the fibers constituting the base fiber layer is too large, the wiped dust may come off.

The fiber length of the fibers constituting the base fiber layer is also not particularly limited as long as the base fiber layer supports the ultrafine fiber layer and imparts strength to the entire laminated nonwoven fabric that can withstand use as a wiper. The fiber length of the fibers of the base fiber layer may be appropriately selected according to the manufacturing method of the base fiber layer. For example, when the base fiber layer is produced by making a carded web or by an air laying method, the fibers constituting the base fiber layer may be staple fibers. The lower limit of the fiber length of short fibers may be, for example, 2 mm, especially 20 mm, more especially 28 mm, even more especially 30 mm. The upper limit of the fiber length may be, for example, 100 mm, especially 75 mm, more especially 65 mm, even more especially 20 mm. When producing a carded web, the fiber length may be 20 mm or more and 100 mm or less, particularly 28 mm or more and 75 mm or less, more particularly 30 mm or more and 65 mm or less. If the fiber length is 20 mm or more and 100 mm or less, it may be easier to suppress breakage of the base fiber layer when partially breaking the ultrafine fiber layer. When the base fiber layer is produced by the air laying method, the fiber length may be, for example, 2 mm or more and 20 mm or less.

The basis weight of the base fiber layer is also not particularly limited as long as the base fiber layer supports the ultrafine fiber layer and imparts strength to the entire laminated nonwoven fabric to withstand use as a wiper. The basis weight of the base fiber layer may be, for example, 30 g/m ² or more and 70 g/m ² or less, particularly 35 g/m ² or more and 65 g/m ² or less, and more particularly 40 g/m ² or more and 60 g. /m ² or less. If the fabric weight of the base fiber layer is too small, the laminated nonwoven fabric may not have sufficient strength, and the amount of liquid that can be retained may decrease. If the fabric weight of the base fiber layer is too large, the entangling property with the fibers of the ultrafine fiber layer may decrease.

In this embodiment, the base fiber layer may be composed of rayon and polyethylene terephthalate monofilaments. In that case, the proportion of rayon may be, for example, 5% by mass or more and 50% by mass or less, particularly 7% by mass or more and 30% by mass or less, and more particularly 10% by mass or more and 20% by mass or less. The fiber length of the rayon and polyethylene terephthalate single fibers may be 30 mm or more and 60 mm or less when the substrate fiber layer is manufactured by making a card web. Furthermore, the basis weight of the base fiber layer composed of a combination of rayon and polyethylene terephthalate single fibers may be 30 g/m ² or more and 70 g/m ² or less.

(Unification of ultrafine fiber layer and base fiber layer)
In the laminated nonwoven fabric of this embodiment, the ultrafine fiber layer and the base fiber layer are integrated by entangling the fibers. The fibers may be entangled and integrated by an entanglement treatment method using a high-pressure fluid flow, as described later. In this embodiment, it is preferable that the fibers constituting the base fiber layer and the fibers constituting the ultrafine fiber layer are not bonded together by an adhesive or melting of one component of the fibers. If these fibers adhere to each other, less movement of the fibers during wiping can adversely affect wiping performance.

(Laminated nonwoven fabric)
The basis weight of the laminated nonwoven fabric obtained by integrating the ultrafine fiber layer and the base fiber layer may be, for example, 30 g/m ² or more and 100 g/m ² or less, particularly 40 g/m ² or more and 90 g/m ² or less. well, more particularly 50 g/m ² or more and 80 g/m ² or less. If the basis weight of the laminated nonwoven fabric is too small, the nonwoven fabric may not have sufficient strength, and the handleability may deteriorate. If the basis weight of the laminated nonwoven fabric is too large, the integration of the ultrafine fiber layer and the base fiber layer becomes insufficient, and delamination may occur.

(Manufacturing method of laminated nonwoven fabric)
Next, a method for manufacturing the laminated nonwoven fabric of this embodiment will be described.
The laminated nonwoven fabric of this embodiment can be manufactured by the following manufacturing methods, for example.
a first hydroentangling step of hydroentangling the substrate fiber web;
After the first hydroentanglement treatment step, a lamination step of laminating an ultrafine fiber web containing ultrafine fibers with a fiber diameter of 0.01 μm to 10 μm on the base fiber web to form a laminated fiber web;
a second hydroentangling treatment step of hydroentangling from the surface of the ultrafine fiber web of the laminated fiber web;
After the second hydroentangling treatment step, a widening step of laterally widening the laminated fiber web by a factor of 1.05 to 1.50 to partially break the ultrafine fiber web;
A method for producing a laminated nonwoven fabric, comprising a third hydroentangling treatment step of subjecting the laminated fibrous web to a hydroentangling treatment after the widening step.
Hereinafter, according to this manufacturing method, the form which manufactures the laminated nonwoven fabric of this embodiment is demonstrated.

First, a base fiber web that forms a base fiber layer is hydroentangled (first hydroentanglement step). The substrate fibrous web can be, for example, any of carded webs such as parallel webs, cross webs, semi-random webs and random webs, and air laid webs. The base fibrous web may be a laminate of webs of the same type or different types.

The hydroentanglement treatment of the base fibrous web is carried out to entangle the fibers of the base fibrous web and form the base fibrous web into a sheet before laminating the ultrafine web. If the ultrafine fiber web is laminated without hydroentangling the substrate fibrous web and the laminated fibrous web is hydroentangled, the ultrafine fiber web and the substrate fibrous web may not be integrated well.

In particular, when a melt-blown nonwoven fabric is used as the ultrafine fiber web, it is preferable that the base fiber web is formed into a sheet in advance. Melt-blown nonwoven fabrics tend to weaken the water pressure of the water flow, and when the base fiber web is not in the form of a sheet, the water pressure is increased in order to entangle the fibers in the base fibers and integrate the base fibers and the ultrafine fiber web. must be integrated. However, the high-pressure water flow may damage the meltblown nonwoven fabric, making it impossible to obtain the laminated nonwoven fabric of the present embodiment. Therefore, in this manufacturing method, the substrate fiber web is made into a sheet form in advance so that it is not necessary to increase the water pressure in the second hydroentangling treatment step described later.

In the first hydroentangling step, for example, the substrate fiber web is placed on a plain weave support of 80 mesh or more and 100 mesh or less, and the orifice having a hole diameter of 0.05 mm or more and 0.5 mm or less is 0.3 mm or more. It may be carried out by jetting a water stream with a water pressure of 1 MPa or more and 15 MPa or less onto the front and back surfaces of the fiber web 1 to 5 times each from nozzles provided at intervals of 5 mm or less. The water pressure is preferably 1 MPa or more and 10 MPa or less, more preferably 1 MPa or more and 7 MPa or less.

After the first hydroentangling treatment step and before the later-described lamination step, the base fiber web may be subjected to a stretching step in which it is longitudinally stretched by a factor of 1.05 to 1.50. The magnification of the stretching process may be the same as the magnification of the widening process, which will be described later. In that case, the dimensions of the nonwoven fabric after the widening process should be the same as the dimensions of the base fiber web after the first hydroentangling treatment. can be done. Alternatively, the magnification of the stretching process may be different from the magnification of the widening process. By carrying out the stretching step, the laminated fiber web can be easily widened in the lateral direction in the later widening step, and the widening step can be carried out smoothly.

The stretching step may be performed by, for example, using two nip rolls, sandwiching the base fiber layer between the rolls, and making the speed of the nip roll on the traveling direction side higher than the speed of the other nip roll. By adjusting the difference in speed, it is possible to stretch at a desired magnification.

After the first hydroentangling treatment step or the stretching step, a superfine fiber web is laminated on the base fiber web to obtain a laminated fiber web (lamination step). The ultrafine fiber web serves as the ultrafine fiber layer and contains ultrafine fibers with a fiber diameter of 0.01 μm to 10 μm. A meltblown nonwoven fabric may be prepared as the ultrafine fiber web and laminated to the base fiber web. By using the meltblown nonwoven fabric, it is possible to conveniently partially break the ultrafine fiber layer in the widening step described later. The ultrafine fiber web may be laminated onto the base fibrous web by accumulating fibers directly on the base fibrous web by meltblowing or electrospinning.

As the ultrafine fiber web, for example, one having a tensile strength in the MD direction of 1.0 N/5 cm or more and 30 N/5 cm or less may be used. The mechanical properties of the ultrafine fiber web described here are those measured before laminating the ultrafine fiber web onto the substrate fiber web (the same applies hereinafter). When the tensile strength in the MD direction of the ultrafine fiber web is within this range, it is preferable in that breakage due to tension during transportation hardly occurs. The tensile strength in the MD direction of the microfiber web may be in particular 2.0 N/5 cm or more and 20 N/5 cm or less, more particularly 3.0 N/5 cm or more and 15 N/5 cm or less.

As the ultrafine fiber web, for example, a web having a tensile strength in the CD direction of 0.5 N/5 cm or more and 12 N/5 cm or less may be used. When the tensile strength in the CD direction of the ultrafine fiber web is within this range, the ultrafine fiber web can be conveniently partially broken during widening. The tensile strength in the CD direction of the microfiber web may in particular be 1.0 N/5 cm or more and 10 N/5 cm or less, more particularly 1.5 N/5 cm or more and 6.0 N/5 cm or less.

As the ultrafine fiber web, for example, one having an elongation percentage in the MD direction of 1.0% or more and 30% or less may be used. When the elongation percentage in the MD direction of the ultrafine fiber web is within this range, excessive elongation of the ultrafine fiber layer during cutting of the laminated nonwoven fabric can be suppressed. The elongation percentage of the microfiber web in the MD direction may be particularly 2.0% or more and 25% or less, more particularly 3.0% or more and 20% or less.

As the ultrafine fiber web, for example, a web having an elongation percentage in the CD direction of 10% or more and 55% or less may be used. If the elongation rate of the ultrafine fiber web in the CD direction is within this range, the ultrafine fiber web can be prevented from being randomly broken during widening, the breakage can be easily controlled, and the ultrafine fiber web can be stretched only during widening. It is possible to suppress the inconvenience that breakage does not occur at. The elongation in the CD direction of the microfiber web may be in particular 15% or more and 50% or less, more particularly 20% or more and 45% or less.

As the ultrafine fiber web, for example, one having a stress at 10% elongation in the MD direction of 0.5 N/5 cm or more and 30 N/5 cm or less may be used. When the stress at 10% elongation in the MD direction of the ultrafine fiber web is within this range, breakage due to tension during transportation is less likely to occur. The stress at 10% elongation in the MD direction of the ultrafine fiber web may be particularly 1.0 N/5 cm or more and 20 N/5 cm or less, more particularly 1.5 N/5 cm or more and 15 N/5 cm or less.

As the ultrafine fiber web, for example, one having a stress at 10% elongation in the CD direction of 0.1 N/5 cm or more and 7.0 N/5 cm or less may be used. If the stress at 10% elongation in the CD direction of the microfiber web is within this range, the microfiber web can be conveniently partially broken during widening. The stress at 10% elongation in the CD direction of the ultrafine fiber web may be particularly 0.4 N/5 cm or more and 6.0 N/5 cm or less, more particularly 0.8 N/5 cm or more and 5.0 N/5 cm or less. good.

Subsequently, the laminated fiber web is subjected to a hydroentanglement treatment from the surface of the ultrafine fiber web (second hydroentanglement step). In the second hydroentangling step, for example, the substrate fiber web is placed on a plain weave support of 80 mesh or more and 100 mesh or less, and the orifice having a hole diameter of 0.05 mm or more and 0.5 mm or less is 0.3 mm or more. It may be carried out by spraying a water stream with a water pressure of 1 MPa or more and 15 MPa or less onto the surface of the ultrafine fiber web 1 to 3 times from nozzles provided at intervals of 5 mm or less. The water pressure is preferably 1 MPa or more and 10 MPa or less, more preferably 1 MPa or more and 7 MPa or less. In the second hydroentangling treatment, nozzle streaks are formed in the ultrafine fiber layer by jetting water jets from nozzles. It is believed that the regular spacing of the nozzle lines and the appropriate number of nozzle lines facilitate breaking of the ultrafine fiber web (ultrafine fiber layer) in the widening step described later. Therefore, the water stream is jetted only to the surface of the ultrafine fiber web and is not jetted to the surface of the base fiber layer. If the water stream is also injected onto the surface of the base material fiber layer, the intervals between the nozzle lines may not be regular, and the number of nozzle lines may become too large. In order to make the intervals of the nozzle streaks regular, the water stream is preferably jetted once onto the surface of the ultrafine fiber web.

After the second hydroentangling treatment step, the laminated fiber web is subjected to a widening step of laterally widening by 1.05 times or more and 1.50 times or less. The widening step is performed to partially break the microfiber web so that the microfiber web (microfiber layer) forms a plurality of stripes along the longitudinal direction of the nonwoven fabric. The magnification of the width-enlarging step may be particularly 1.10 times or more and 1.45 times or less, more particularly 1.15 times or more and 1.35 times or less. If the magnification of the widening step is too small, partial breakage of the microfiber layer may not occur, and if the magnification is too large, the distance between the striations in the microfiber layer, i.e., the distance between the striations increases. Sometimes too much. By subjecting the superfine fiber web and the base fiber web to the widening step in a state in which they are laminated, it is possible to relatively freely break the ultrafine fiber web, for example, to break it to a large extent. When only the ultrafine fiber web is subjected to the widening step without the ultrafine fiber web and the base fiber web being laminated, the ultrafine fiber web tends to break due to the tension during transportation if the magnification of the width increasing step is too large. Conceivable.

The widening step may be performed using rolls as shown in FIG. The rolls shown in FIG. 1 are a combination of rolls having a large number of grooves formed on the surface. (part with an acute angle). The direction in which the grooves 12 and 22 extend is parallel to the longitudinal direction of the laminated fibrous web. Therefore, the rolls 10 and 20 have a shape in which regular irregularities are repeatedly formed in the lateral direction of the laminated fibrous web. there is By changing the width w and depth d of the grooves 12 and 22 of these rolls 10 and 20 and the distance (clearance) between the rolls 10 and 20, the widening magnification can be adjusted. For example, if the width w of the grooves 12, 22 is constant, the distance between the two rolls may be shorter and/or the depth d of the grooves 12, 22 may be greater (i.e. constitute the grooves in cross-section By using the rolls 10 and 22 having a larger oblique side length f, the widening ratio can be increased. Further, by making the width w of the grooves 12 and 22 of the rolls smaller, there is a tendency that the widening can be performed more uniformly.

When the laminated fibrous web is introduced between these two rolls, in each groove 12 the lateral dimension of the laminated fibrous web, i.e. the width, extends along the shape of the groove 12, so that the laminated fibrous web Width will be widened. The laminated fibrous web, which has been widened to conform to the shape of the grooves 12, may have pleats corresponding to the shape of the grooves 12 as it exits the rolls 10,20. Therefore, if necessary, the widened laminated fiber web may be flattened using an expander or the like in order to widen the pleats.

The laminated fiber web after the widening treatment is further subjected to a hydroentangling treatment (third hydroentangling treatment step). The third hydroentangling step is performed to fix the ultrafine fiber layer, which has been partially broken and present as a plurality of streaks due to the widening, to the base fiber layer. In the third hydroentangling step, for example, the substrate fiber web is placed on a plain weave support of 80 mesh or more and 100 mesh or less, and the orifices having a hole diameter of 0.05 mm or more and 0.5 mm or less are 0.3 mm or more. It may be carried out by jetting a water stream with a water pressure of 1 MPa or more and 15 MPa or less onto the front and back surfaces of the fiber web 1 to 5 times each from nozzles provided at intervals of 5 mm or less. The water pressure is preferably 1 MPa or more and 10 MPa or less, more preferably 1 MPa or more and 7 MPa or less.

After completion of the third hydroentangling treatment step, the laminated fibrous web may optionally be subjected to a drying treatment. The drying treatment may be performed using, for example, a hot air penetration heat treatment machine (also called an air through heat treatment machine), a hot air blowing heat treatment machine, an infrared heat treatment machine, or the like. When the ultrafine fiber layer and the base fiber layer contain synthetic fibers, the drying temperature should be that of the thermoplastic resin that makes up the synthetic fibers (the thermoplastic resin with the lowest melting point if multiple thermoplastic resins make up the fibers). The temperature may be set below the melting point. As a result, the fibers of the ultrafine fiber layer and the fibers of the base fiber layer are not thermally bonded, and a laminated nonwoven fabric having a soft texture can be obtained.
Thus, the laminated nonwoven fabric of this embodiment can be obtained.

(wiper)
The laminated nonwoven fabric of this embodiment is suitable for use as a wiper. The laminated nonwoven fabric of this embodiment may be used as a wiper as it is. Alternatively, a wiper obtained by laminating another base material to the base fiber layer of the laminated nonwoven fabric of the present embodiment may be used. The wiper may be held by hand and used like a dust cloth, or may be used by being attached to a jig having a wiper attachment portion at the end of a rod-like object.

The wiper may be anti-personnel or objective.
A wiper for personal use may be used for wiping off dirt, cosmetics, medicines, or the like attached to a person's body. For the personal wiper, for example, 100 parts by mass of the nonwoven fabric may be impregnated with water or an aqueous solution containing a cleaning component in an impregnation amount of 100 parts by mass or more and 1000 parts by mass or less. Liquid-impregnated personal wiping sheets are more specifically provided as, for example, hand wipes, baby wipes, menstrual blood wipes, makeup remover sheets, face wash sheets, antiperspirant sheets, and nail removers.

Objective wipers may be used for wiping floors, kitchens, toilets, bathtubs, furniture, vehicles, walls, screens and windows, and the like. The objective wiper may be impregnated with, for example, 100 parts by weight or more and 1000 parts by weight or less of an impregnation amount of water or an aqueous solution containing a cleaning component with respect to 100 parts by weight of the nonwoven fabric.

Any wiper is preferably used so that the wiping surface is the surface of the ultrafine fiber layer. The ultrafine fibers contained in the ultrafine fiber layer can effectively wipe off fine powdery stains. In addition, since the ultrafine fiber layer is partially broken to form streaks, dirt wiped off can be retained between the streaks, and clogging is less likely to occur in the ultrafine fiber layer. A wiper can also wipe off a relatively large amount of fine powdery dirt. That is, according to the laminated nonwoven fabric of the present embodiment, it is possible to obtain a wiper with a longer number of times of wiping or a longer period of time before replacement. Therefore, the laminated nonwoven fabric of the present embodiment is particularly suitable for use as a wiper for flooring which is easily soiled by fine powder, especially dust.

Furthermore, the wiper using the laminated nonwoven fabric of the present embodiment is less prone to twisting in the ultrafine fiber layer during wiping. This is because the ultrafine fiber layer is partially broken, so that the surface of the nonwoven fabric includes a portion where the ultrafine fiber layer exists and a portion where the ultrafine fiber layer does not exist. it is conceivable that. This also enables the wiper using the laminated nonwoven fabric of this embodiment to be used for a long period of time.

Hereinafter, the laminated nonwoven fabric of the present embodiment and the wiper using the same will be described with reference to examples.
The following fibers were prepared as fibers used in this example.
Rayon fiber: Viscose rayon having a fineness of 1.7 dtex (fiber diameter of 12 μm) and a fiber length of 40 mm (trade name: Corona CD, manufactured by Daiwabo Rayon Co., Ltd.).
Polyester fiber: Polyethylene terephthalate single fiber having a fineness of 1.45 dtex and a fiber length of 38 mm (trade name: T403D, manufactured by Toray).

The following meltblown nonwoven fabrics were prepared for use in this example.
Melt-blown non-woven fabric having a basis weight of 15 g/m ² and a thickness of 0.14 mm (under a load of 294 Pa) made of polypropylene resin single fibers having an average fiber diameter of 2.0 µm The mechanical properties of this melt-blown non-woven fabric were as follows.
MD tensile strength 9.7N/5cm
CD tensile strength 4.4N/5cm
MD elongation 13.0%
CD elongation 33.4%
MD 10% elongation stress 9.3N/5cm
CD10% elongation stress 3.2N/5cm

(Example 1)
(Process for producing card web)
Rayon fibers and polyester fibers were mixed at a mass ratio of 15:85, and a parallel carding machine was used to prepare a parallel staple fiber web with a web target weight of about 53 g/m ² .

(First hydroentanglement treatment step)
A staple fiber web was placed on a 90-mesh plain weave support and conveyed at a speed of 4 m/min, and a water jet with a water pressure of 3.0 MPa was jetted once from one surface side, followed by another. A water flow entangling treatment was performed by jetting a water flow with a water pressure of 3.0 MPa once from the surface side. The nozzle used in the hydroentanglement treatment was a nozzle with orifices of 0.1 mm diameter and 0.6 mm intervals, and the distance between the nozzle and the staple fiber web was 20 mm during the treatment.

(Elongation process)
The staple fiber web was stretched 1.2 times in the machine direction (MD direction) between two nip rolls.

(Second hydroentanglement treatment step)
A melt-blown nonwoven fabric is laminated on the staple fiber web after the elongation process, and using the same equipment as used in the first hydroentanglement process, a water jet with a water pressure of 4.0 MPa is jetted once from the meltblown nonwoven fabric side. As a result, a laminated nonwoven fabric web was obtained in which the staple fiber web was used as the base fiber web and the meltblown nonwoven fabric was used as the ultrafine fiber web.

(widening process)
The laminated nonwoven fabric web is widened 1.2 times in the width direction (CD direction) by widening rolls (groove depth d 2.0 mm, groove width w 3.0 mm, oblique side length f 2.5 mm constituting the groove in cross section). let me

(Third hydroentanglement treatment step)
Using the same device as used in the first hydroentanglement treatment step, a water jet with a water pressure of 5.0 MPa is jetted once from the ultrafine fiber web (meltblown nonwoven fabric) side, and then 5 times from the base fiber web side. A hydroentanglement treatment was performed by injecting a water flow having a water pressure of 0 MPa once.

(Drying process)
A drying treatment was performed using a hot air penetrating heat treatment machine set at 80° C. to obtain a laminated nonwoven fabric of Example 1.
In the laminated nonwoven fabric of Example 1, apart from the nozzle streaks formed by the hydroentangling treatment, the meltblown nonwoven fabric layer has parts where it is partially broken in the CD direction of the nonwoven fabric, and in the ultrafine fiber layer, along the longitudinal direction of the nonwoven fabric Multiple streaks were formed extending along the

(Comparative example 1)
A laminated nonwoven fabric of Comparative Example 1 was obtained in the same manner as in Example 1, except that the elongation step and the widening step were not performed.
Table 1 shows the measurement and evaluation results of the physical properties of each example and each comparative example.

Each physical property in the table was measured by the following method.

[thickness]
The thickness of the non-woven fabric when dry (dry) is measured using a thickness measuring machine (trade name: THICKNESS GAUGE Model CR-60A, manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.) with loads of 294 Pa and 1.96 kPa applied. bottom.

[Tensile strength, elongation, stress at 10% elongation]
According to JIS L 1913: 2010 6.3, using a constant-speed tension type tensile tester, the sample piece was subjected to a tensile test under the conditions of a width of 50 mm, a grip interval of 10 cm, and a tensile speed of 30 ± 2 cm / min, and cut. The load value (tensile strength), elongation, stress at 10% elongation, and stress at 20% elongation were measured. The tensile test was carried out with the machine direction (MD direction) and the transverse direction (CD direction) of the nonwoven fabric as tensile directions. Each evaluation result is shown as an average of values measured for three samples.

[Static Friction Coefficient, Dynamic Friction Coefficient, Variation Coefficient of Dynamic Friction Coefficient]
The coefficient of static friction μs, the coefficient of dynamic friction μk, and the coefficient of variation CV of the coefficient of dynamic friction were measured using a static/dynamic friction measuring machine (Tribomaster TL201Ts, manufactured by Trinity Lab Co., Ltd.). A nonwoven fabric of 5 cm x 10 cm was prepared as a sample piece. A sample piece having a long side in the lateral direction (CD direction) of the nonwoven fabric was prepared.

A tactile contactor (manufactured by Trinity Lab Co., Ltd.) was used as the contact terminal of the measuring device. With 100 parts by mass of the sample piece impregnated with 300 parts by mass of distilled water, attach the sample piece to the contact terminal (contact area 5.0 cm × 6.5 cm), and place it on the measurement table of the measuring machine (sliding table type). On the other hand, the test piece was brought into contact with a load of 100 gf, and was moved back and forth twice at a speed of 10 mm/sec and a distance of 30 mm for evaluation. The value of the second reciprocation was read, and the average value of the forward and backward values was taken as the dynamic frictional force (gf) of one sample piece. Also, the average value of the numerical value at the beginning of the forward movement of the second reciprocation and the numerical value at the beginning of the return movement was taken as the static friction force (gf) of one sample piece. Three test pieces were measured, and the average value of the three measurements was taken as static friction force Fs (gf) and dynamic friction force Fk (gf) for each example and comparative example.

A static friction coefficient μs and a dynamic friction coefficient μk were calculated from the static friction force Fs (gf), the dynamic friction force Fk (gf), and the load (100 gf). Further, the variation coefficient CV of the dynamic friction coefficient was obtained according to the following formula from the standard deviation σ of the dynamic friction coefficient obtained during the measurement and the average value μk of the dynamic friction coefficient.
Variation coefficient of dynamic friction coefficient CV = σ/μk

[Dust trapping]
0.20 g of test powder (7 types) according to JIS Z 8901 is evenly dispersed in a rectangular area of 5 cm long x 15 cm wide (hereinafter referred to as "dust dispersion area") approximately in the center of the surface of a white acrylic plate. The dust was wiped off using the laminated nonwoven fabric (length 26 cm, width 16 cm) of Examples and Comparative Examples as a wiper.

The wiping was performed by impregnating 100 parts by mass of the nonwoven fabric with 300 parts by mass of distilled water. In addition, the area contributing to wiping is 26 cm in the vertical direction and 16 cm in the horizontal direction. , manufactured by Kao Corporation) and a load of 400 g was applied. Wiping was performed by reciprocating the wiper once on the surface of the white acrylic plate.

More specifically,
・Place the wiper in the center of the dust distribution area so that the vertical direction of the wiper matches the vertical direction of the dust distribution area,
・From there, move the wiper by 250mm in the direction toward the left end of the dust dispersion area to rub the dust (white acrylic plate),
・Then, after moving the wiper 500mm in the direction toward the right edge of the dust dispersion area,
・Furthermore, the wiper was moved 250 mm in the direction toward the left end of the dust dispersion area, and the wiper was reciprocated once.

After one reciprocation of the wiper, the state of the wiped surface of the laminated nonwoven fabric and the state of the white acrylic plate were visually observed and evaluated according to the following evaluation criteria. For each laminated nonwoven fabric, wiping was performed three times with a new wiping surface of the nonwoven fabric, and the wiping surface of the nonwoven fabric and the surface of the white acrylic plate after wiping were observed and evaluated.
A: Sufficiently wiped off.
◯: Wiped off to some extent.
Δ: Insufficient wiping.

[Hair collecting property]
Five hairs (approximately 5 cm in length) were placed on the flooring at intervals, three horizontally and two vertically, and the hairs were wiped off with the laminated nonwoven fabrics of Examples and Comparative Examples.

The wiping was performed by impregnating 100 parts by mass of the nonwoven fabric with 300 parts by mass of distilled water. For wiping, wipe the laminated nonwoven fabric with a wiper jig (trade name: Quickle wiper [tool body]) so that the area contributing to wiping is 26 cm in the vertical direction and 16 cm in the horizontal direction, and the ultrafine fiber layer becomes the wiping surface. (manufactured by Kao Corporation), and a weight of 400 g was applied. The wiping was carried out by reciprocating the wiper once over the hair in the same manner as the method employed in the evaluation of the dust collection property. After wiping, the hair collection rate (%) was obtained from the number of hairs wiped from the flooring. For each laminated nonwoven fabric, the wiping was measured three times with the wiping surface of the nonwoven fabric being renewed, and the average value was taken as the hair collection rate.

[Sustained release]
100 parts by mass of the nonwoven fabric is impregnated with 300 parts by mass of distilled water, and the area contributing to wiping is 26 cm in the vertical direction and 16 cm in the horizontal direction. It was attached to a tool (trade name: head of Quickle Wiper [tool body], manufactured by Kao Corporation). With a load of 400 g applied, it was placed on the conveyor so that the direction of movement of the conveyor coincided with the transverse direction (16 cm) of the nonwoven fabric, and the conveyor was run at 5 m/min. The wiping area at the time when the conveyor was no longer wet was calculated by converting it into the number of tatami mats.

[State of ultrafine fiber layer]
As the state of the ultrafine fiber layer, the average width of the stripes formed by the ultrafine fiber layer in the direction parallel to the horizontal direction of the nonwoven fabric, the average spacing between the stripes, and the area ratio of the ultrafine fiber layer on the surface of the nonwoven fabric were measured. .
First, the laminated nonwoven fabric was dyed under the following conditions.
(A) Pretreatment: Laminated nonwoven fabric was added to a treatment liquid in which SUNMORL HS-B (refining agent, manufactured by Nicca Chemical Co., Ltd.) was dissolved at a concentration of 0.5 g / L at a bath ratio of 1:15, After being immersed at 90° C. for 30 minutes, it was washed with hot water and then with water.
(B) Staining: Kayalon Polyester Naby Blue 2GN(H)-211 (disperse dye, manufactured by Nippon Kayaku Co., Ltd.) at 8.0% owf, Colorsol ACE-191 (dyeing aid, Daiichi Kogyo Seiyaku Co., Ltd. ) at a rate of 2.0 g/L and further containing 80% acetic acid at a rate of 0.5 cc/L. and immersed at 130° C. for 60 minutes.
(C) Reduction cleaning: 2.0 g/L of hydrosulfite (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) and 4.5 g/L of NaOH (38° Be) (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) , and Escudo NS-80 (soaping agent, manufactured by Nicca Chemical Co., Ltd.) at a ratio of 2.5 g / L was prepared. After being immersed at ℃ for 20 minutes, it was washed with hot water and then with water.

The laminated nonwoven fabric was magnified with an optical microscope, and the surface of the melt-blown nonwoven fabric layer (area of 2.0 mm×3.0 mm) was observed and photographed. From the photograph, it was confirmed that the ultrafine fiber layer (meltblown nonwoven fabric) was not dyed, and only the base fiber layer was dyed.
In this photograph, the lateral (CD) width of the unstained muscle was measured. The measurement was performed by the method described above, and the average value of the measured values at 42 points was taken as the average width of the stripes formed by the ultrafine fiber layer in the horizontal direction.
Similarly, the interval (distance) between adjacent muscles was measured by the method described above, and the average value of the measured values at 21 points was taken as the average interval between adjacent muscles.

In the photograph, the area ratio of the ultrafine fiber layer was measured by calculating the total area of the undyed portion and calculating the ratio of this to the entire nonwoven fabric shown in the photograph. The average value of the area ratios of the 10 photographs was obtained, and this was taken as the area ratio of the ultrafine fiber layer on the nonwoven fabric surface in each example or each comparative example.

A wiper using the nonwoven fabric of Example 1 exhibited excellent dust collecting properties. More specifically, more dust was collected on the wiping surface of the wiper after wiping off the dust, and it was confirmed that the dust was particularly mixed between the lines of the ultrafine fiber layer. . Since the wiper using the nonwoven fabric of Comparative Example 1 was manufactured without widening the laminated fiber web, partial breakage of the ultrafine fiber layer was observed in the portion hit by the water flow in the hydroentangling treatment, and streaks were formed. Although multiple were formed, the average spacing between streaks was significantly narrower than that of Example 1. Therefore, the dust collection performance was inferior to that of Example 1, and the amount of collected dust was clearly smaller than that of Example 1 even when the surface of the wiper after wiping was observed.

Example 1 was slightly superior to Comparative Example 1 in hair collection rate. This is probably because, in Example 1, the portion where the ultrafine fiber layer does not exist (partially broken portion) has a size larger than that in Comparative Example 1, as described above.

In Example 1, the mechanical strength tended to be lower than in Comparative Example 1 because the ultrafine fiber layer was further broken by widening. There was almost no difference between the static friction coefficient μs and the dynamic friction coefficient μk of Example 1 and Comparative Example 1, but the variation coefficient of the dynamic friction coefficient of Example 1 was larger than that of Comparative Example 1. This is because in Example 1, between the streaks (between the protrusions), over a relatively long distance in the transverse direction of the nonwoven fabric, such that the recesses (broken portions) are sufficiently reflected in the measurement of the coefficient of variation. It is thought that it depends on existence.

This embodiment includes the following aspects.
(Aspect 1)
A laminated nonwoven fabric comprising an ultrafine fiber layer containing ultrafine fibers with a fiber diameter of 0.01 μm to 10 μm and a base fiber layer,
The ultrafine fiber layer and the base fiber layer are integrated by entangling the fibers,
The ultrafine fiber layer is partially broken to form a plurality of streaks along one direction of the nonwoven fabric,
The average width of one line of the ultrafine fiber layer in a direction orthogonal to one direction of the nonwoven fabric is 0.1 mm to 0.5 mm,
The average spacing between adjacent microfiber layers is 0.7 mm to 1.2 mm,
Laminated nonwoven fabric.
(Aspect 2)
The laminated nonwoven fabric according to aspect 1, wherein the microfiber layer is a meltblown nonwoven fabric.
(Aspect 3)
The laminated nonwoven fabric according to aspect 1 or 2, wherein the microfiber layer has an area ratio of 5% to 30% on the surface of the nonwoven fabric.
(Aspect 4)
The laminated nonwoven fabric according to any one of aspects 1 to 3, wherein the ultrafine synthetic fibers contained in the ultrafine fiber layer and the fibers constituting the base fiber layer are not bonded.
(Aspect 5)
A wiper comprising the laminated nonwoven fabric of any one of aspects 1-4.
(Aspect 6)
a first hydroentangling step of hydroentangling the substrate fiber web;
After the first hydroentanglement treatment step, a lamination step of laminating an ultrafine fiber web containing ultrafine fibers with a fiber diameter of 0.01 μm to 10 μm on the base fiber web to form a laminated fiber web;
a second hydroentangling treatment step of hydroentangling from the surface of the ultrafine fiber web of the laminated fiber web;
After the second hydroentangling treatment step, a widening step of laterally widening the laminated fiber web by a factor of 1.05 to 1.50 to partially break the ultrafine fiber web;
A method for producing a laminated nonwoven fabric, comprising a third hydroentangling treatment step of subjecting the laminated fibrous web to a hydroentangling treatment after the widening step.
(Aspect 7)
Production of a laminated nonwoven fabric according to aspect 6, comprising a stretching step of longitudinally stretching the base fibrous web by 1.05 to 1.50 times after the first hydroentangling treatment step and before the laminating step. Method.
(Aspect 8)
A method for producing a laminated nonwoven fabric according to aspect 6 or 7, wherein the microfiber web is a meltblown nonwoven fabric.

The laminated nonwoven fabric of the present embodiment is formed by integrating the ultrafine fiber layer and the base fiber layer, and on the surface of the nonwoven fabric, the part where the ultrafine fiber exists and the part where the ultrafine fiber does not exist alternately in stripes. It is useful as a wiper capable of wiping off dust over a long period of time.

10 Roll 12 Groove 20 Roll 22 Groove 24 Serration

Claims (8)

A laminated nonwoven fabric comprising an ultrafine fiber layer containing ultrafine fibers with a fiber diameter of 0.01 μm to 10 μm and a base fiber layer,
The ultrafine fiber layer and the base fiber layer are integrated by entangling the fibers,
The ultrafine fiber layer is partially broken to form a plurality of streaks along one direction of the nonwoven fabric,
The average width of one line of the ultrafine fiber layer in a direction orthogonal to one direction of the nonwoven fabric is 0.1 mm to 0.5 mm,
The average spacing between adjacent microfiber layers is 0.7 mm to 1.2 mm,
Laminated nonwoven fabric. 2. The laminated nonwoven fabric according to claim 1, wherein said microfiber layer is a meltblown nonwoven fabric. 3. The laminated nonwoven fabric according to claim 1, wherein the microfiber layer has an area ratio of 5% to 30% on the surface of the nonwoven fabric. The laminated nonwoven fabric according to any one of claims 1 to 3, wherein the ultrafine synthetic fibers contained in the ultrafine fiber layer and the fibers constituting the base fiber layer are not bonded. A wiper comprising the laminated nonwoven fabric according to any one of claims 1-4. a first hydroentangling step of hydroentangling the substrate fiber web;
After the first hydroentanglement treatment step, a lamination step of laminating an ultrafine fiber web containing ultrafine fibers with a fiber diameter of 0.01 μm to 10 μm on the base fiber web to form a laminated fiber web;
a second hydroentangling treatment step of hydroentangling from the surface of the ultrafine fiber web of the laminated fiber web;
After the second hydroentangling treatment step, a widening step of laterally widening the laminated fiber web by a factor of 1.05 to 1.50 to partially break the ultrafine fiber web;
A method for producing a laminated nonwoven fabric, comprising a third hydroentangling treatment step of subjecting the laminated fibrous web to a hydroentangling treatment after the widening step. 7. The lamination according to claim 6, comprising a stretching step of longitudinally stretching the base fibrous web by 1.05 to 1.50 times after the first hydroentangling treatment step and before the laminating step. A method for manufacturing a nonwoven fabric. 8. The method for producing a laminated nonwoven fabric according to claim 6 or 7, wherein said ultrafine fiber web is a meltblown nonwoven fabric.

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