Method for manufacturing water-entangled nonwoven fabric

Abstract

This invention provides a method for manufacturing a water-entangled nonwoven fabric that is less prone to water flow marks. [Solution] A laminate is prepared by laminating paper made of ultrafine short fibers and a pique knit fabric made of yarn. The pique knit fabric used has three courses 10 in which only loops exist, and on both sides of the wale direction of these three courses 10, there is a first course 11 in which tucks and loops alternately exist in the course direction, and a second course 12 in which loops and tucks alternately exist in the course direction. The positions of tuck 1 and loop 2 in the first course 11 and the second course 12 are offset by one stitch in the weft. The laminate is passed through a high-pressure water jet spray device and a water flow is applied to entangle the ultrafine short fibers with each other and with the pique knit fabric to obtain a water-entangled nonwoven fabric.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a water-crosslinked nonwoven fabric with inconspicuous water flow marks, and particularly to a method for manufacturing a water-crosslinked nonwoven fabric effective for use as a base fabric for artificial leather.

Background Art

[0002] Conventionally, it has been proposed to laminate paper composed of ultrafine short fibers and a woven fabric, apply water flow to this, and use a nonwoven fabric in which the ultrafine short fibers are crosslinked with each other and with the woven fabric as a base fabric for artificial leather (Patent Documents 1 and 2). In Patent Document 1, it is described that a plain weave or a gauze weave is used as the woven fabric. Also, in Patent Document 2, it is described that a Raschel weave having a hexagonal tulle pattern used as a base fabric for embroidery lace is used.

[0003] However, since plain weaves and gauze weaves have a homogeneous structure, there is a drawback that water flow marks remain on the surface of the nonwoven fabric obtained by applying water flow and are conspicuous. Also, the Raschel weave used as a base fabric for embroidery lace has large holes through which embroidery needles can easily pass, so there is a drawback that ultrafine short fibers are likely to fall off through these holes due to water flow, and there is also a drawback that water flow marks still remain and are conspicuous.

[0004]

Patent Document 1

Patent Document 2

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a method for manufacturing a water-crosslinked nonwoven fabric with inconspicuous water flow marks.

Means for Solving the Problems

[0006] The present invention solves the above problem by applying a water flow treatment to a laminate formed by laminating paper and a specific type of pique knit fabric. Specifically, the present invention relates to a method for producing a water flow entangled nonwoven fabric, in which a water flow is applied to a laminate formed by laminating paper composed of ultrafine short fibers and a pique knit fabric composed of yarn, thereby entangling the ultrafine short fibers with each other and the pique knit fabric with the pique knit fabric. Here, a pique knit fabric is a knit fabric in which there are multiple courses in which only loops exist, and on both sides of the wale direction of the multiple courses, there are a first course in which tucks and loops alternately exist in the course direction and a second course in which loops and tucks alternately exist in the course direction, and the positions of the tucks and loops in the first course and the second course are shifted in the weft.

[0007] The ultrafine staple fibers used in this invention are those that are conventionally known. The fiber diameter of the ultrafine staple fibers is preferably 10 μm or less, and more preferably 5 μm or less. The fiber length is preferably 3 to 20 mm, and more preferably 5 to 10 mm. Such ultrafine staple fibers can be obtained by conventionally known methods, for example, by the same methods used to obtain conventional short-cut fibers. As the material for the ultrafine staple fibers, any material such as cellulose, polyolefin, polyester such as polyethylene terephthalate, polyamide, or acrylic can be used. Polyethylene terephthalate is particularly preferred because it has excellent weather resistance. To ensure the homogeneity of the resulting water-entangled nonwoven fabric, it is preferable to use the same material for the ultrafine staple fibers as for the yarn.

[0008] Paper composed of ultrafine short fibers is obtained by papermaking using ultrafine short fibers. For example, paper on the papermaking machine after papermaking, or paper containing moisture, i.e., paper in the form of a sheet of paper, is also included in the definition of paper in this invention. Of course, general paper obtained by drying after papermaking is also included. It is preferable to use synthetic fiber paper for such paper. Synthetic fiber paper is obtained by dispersing ultrafine short fibers in water to form a slurry, then papermaking and drying this slurry to bond the ultrafine short fibers together. Bonding the ultrafine short fibers together is generally done with a binder. As a binder, it is preferable to use a water-soluble binder such as water-soluble polyvinyl alcohol so that it dissolves in the subsequent step of applying water.

[0009] While conventionally known yarns can be used to construct pique knit fabrics, it is particularly preferable to use multifilament yarn or spun yarn. Multifilament yarn is made up of multiple filaments bundled together, and in the subsequent water flow process, ultrafine short fibers easily penetrate between the filaments, resulting in a strong entanglement between the knit fabric and the ultrafine short fibers. As for multifilament yarn, those with a total fineness of about 100 to 300 decitex and about 20 to 80 filaments are used. Spun yarn is obtained by spinning sliver, which is an aggregate of short fibers, and those with a thickness of about 30 to 40 count are used. Furthermore, it is preferable to twist the multifilament yarn to use it as twisted yarn, because twisted yarn has superior shape retention. In addition, when knitting pique knit fabrics, by supplying S-twist yarn (right twist) and Z-twist yarn (left twist) alternately and knitting the course, it is possible to obtain pique knit fabrics with even better shape retention. For example, if knitting is done using only one type of twisted yarn, the edges of the pique knit fabric may curl due to the unwinding of the twisted yarn's torque. By using polyethylene terephthalate (including recycled polyethylene terephthalate) as the multifilament yarn or spun yarn, and polyethylene terephthalate short-cut fibers as the ultrafine short fibers, a water-entangled nonwoven fabric with excellent weather resistance can be obtained. It is preferable to use solution-dyed polyethylene terephthalate as the multifilament yarn, spun yarn, and ultrafine short fibers to eliminate the need for a subsequent dyeing process.

[0010] The pique knit fabric used in this invention consists of multiple courses containing only loops, and on both sides of the wale direction of these courses, there is a first course with alternating tucks and loops in the course direction and a second course with alternating loops and tucks in the course direction, wherein the positions of the tucks and loops in the first and second courses are offset in the weft. An example of such a pique knit fabric can be described below based on the knitting structure diagram in Figure 1. Reference numeral 1 indicates a tuck, and reference numeral 2 indicates a loop. Multiple courses containing only loops are indicated by reference numeral 10. On both sides of the wale direction of the multiple courses 10, there is a first course 11 with alternating tucks and loops in the course direction and a second course 12 with alternating loops and tucks in the course direction. The positions of tuck 1 and loop 2 in the first course 11 and the second course 12 are offset in the weft. In the example shown in Figure 1, the tucks 1 and loops 2 of the first and second courses are formed alternately, one stitch at a time. However, this can be modified, such as one tuck 1 and two loops 2, two tucks 1 and one loop 2, or two tucks 1 and two loops 2. Also, in the example shown in Figure 1, there are three courses, but this can be modified to two courses, four courses, or so.

[0011] Next, paper composed of ultrafine short fibers and a pique knit fabric composed of yarn are laminated together to form a laminate. Then, this laminate is placed on a conveyor belt and subjected to a water flow while being transported. The water flow is applied by passing the laminate through a conventionally known high-pressure water jet device. As the high-pressure water jet device, one with a cylindrical jet hole where the inlet hole diameter and outlet hole diameter are the same, one with a truncated cone-shaped jet hole where the inlet hole diameter is smaller than the outlet hole diameter, or one with an inverted truncated cone-shaped jet hole where the inlet hole diameter is larger than the outlet hole diameter can be used. In particular, combining the latter two makes it possible to obtain a water-entangled nonwoven fabric in which water flow marks are less noticeable. In general, the wale direction of the pique knit fabric is the direction of the machine. The side to which the water flow is applied may be the paper side or the pique knit fabric side. Preferably, the water flow treatment is applied multiple times to both sides. The water jet pressure is about 1.5 to 10 MPa. This water flow treatment causes the ultrafine short fibers that make up the paper to become entangled with the pique knit fabric, and the ultrafine short fibers to become entangled with each other, resulting in a water-entangled nonwoven fabric. For example, if paper is used in which the ultrafine short fibers are bonded to each other with a water-soluble binder such as polyvinyl alcohol, the water flow will dissolve the water-soluble binder, easily releasing the bonds between the ultrafine short fibers, and allowing the ultrafine short fibers to become well entangled with each other and with the pique knit fabric.

[0012] The water-entangled nonwoven fabric obtained by the method according to the present invention can be used for conventionally known applications, but is particularly suitable as a base fabric for artificial leather. That is, artificial leather can be obtained by impregnating the obtained water-entangled nonwoven fabric with a resin such as polyurethane. [Effects of the Invention]

[0013] The pique knit fabric used in the method according to the present invention is not formed solely of loops, but also contains some tucks, which are positioned weft-shifted in the wale direction. Therefore, the water flow marks that occur after water flow is applied to the laminate are obscured by the tucks, resulting in the effect of making the water flow marks less noticeable. [Examples]

[0014] [Preparing synthetic paper] Synthetic paper A: Made of polyethylene terephthalate short-cut fibers with a fiber diameter of approximately 2 μm bonded with polyvinyl alcohol, with a basis weight of 30 g / m². 2 We prepared synthetic fiber paper (manufactured by Ikeda Paper Industry Co., Ltd.). Synthetic paper A': Made of polyethylene terephthalate short-cut fibers with a fiber diameter of approximately 2 μm bonded together with polyvinyl alcohol, with a basis weight of 80 g / m². 2 We prepared synthetic fiber paper (manufactured by Ikeda Paper Industry Co., Ltd.). Synthetic paper B: Made of polyethylene terephthalate short-cut fibers with a fiber diameter of approximately 5 μm bonded together with polyvinyl alcohol, with a basis weight of 50 g / m². 2 We prepared synthetic fiber paper (manufactured by Ikeda Paper Industry Co., Ltd.).

[0015] [Preparing for the pique knit] Polyethylene terephthalate multifilament yarn (167 decitex 48 filaments) was alternately fed into a 28-gauge circular knitting machine as S-twisted yarn and Z-twisted yarn, and knitted in the structure shown in Figure 1. The knitted fabric was widened using a pin tenter at 170°C to prepare a 1600mm wide pique knit fabric.

[0016] [Preparation of the high-pressure water jet device] High-pressure water jet device A: A device was prepared consisting of jet holes with a circular cross-section, an inlet diameter of 0.100 mm, and an outlet diameter of 0.337 mm, arranged in a horizontal row with a spacing of 0.600 mm between the holes. High-pressure water jet ejection device B: A device was prepared consisting of ejection holes with a circular cross-section, an inlet diameter of 0.120 mm, and an outlet diameter of 0.336 mm, arranged in a horizontal row with a spacing of 0.635 mm between the holes. High-pressure water jet ejection device C: A device was prepared consisting of ejection holes with a circular cross-section, an inlet hole diameter of 0.140 mm, and an outlet hole diameter of 0.300 mm, arranged in a staggered pattern in two horizontal rows with a hole spacing of 0.846 mm. High-pressure water jet device D: A device was prepared consisting of jet holes with a circular cross-section, an inlet diameter of 0.356 mm, and an outlet diameter of 0.127 mm, arranged in a horizontal row with a spacing of 0.600 mm between the holes.

[0017] Example 1 The laminate, made by layering the prepared synthetic paper A and the prepared pique knit fabric, was placed on a conveyor belt (net #90) with the pique knit fabric facing downwards, and passed through high-pressure water jet device A, applying a high-pressure water jet from the synthetic paper A side at a jet pressure of 2 MPa. Next, it was passed through high-pressure water jet device B, applying a high-pressure water jet at a jet pressure of 4 MPa. After that, it was passed through high-pressure water jet device C, applying a high-pressure water jet at a jet pressure of 5 MPa, and then again through high-pressure water jet device C, applying a high-pressure water jet at a jet pressure of 8 MPa. Next, the laminate was inverted, and the prepared synthetic paper B was laminated onto the pique knit side. It was then passed through the high-pressure water jet device A, and a high-pressure water jet was applied from the synthetic paper B side at a jet pressure of 2 MPa. Then, it was passed through the high-pressure water jet device B again, and a high-pressure water jet was applied from the synthetic paper A side at a jet pressure of 2 MPa. Furthermore, the laminate was inverted again, and it was passed through the high-pressure water jet device A again, and a high-pressure water jet was applied from the synthetic paper A side at a jet pressure of 3 MPa. After this, the laminate was inverted once more, and it was passed through the high-pressure water jet device C again, and a high-pressure water jet was applied from the synthetic paper B side at a jet pressure of 5 MPa. Finally, it was passed through the high-pressure water jet device C again, and a high-pressure water jet was applied from the synthetic paper B side at a jet pressure of 8 MPa. Finally, after extracting the water derived from the high-pressure water flow, the material was heated at 145°C for 120 seconds to remove the remaining moisture and obtain a water-entangled nonwoven fabric.

[0018] Example 2 The laminate, made by layering the prepared synthetic paper A' and the prepared pique knit fabric, was placed on a conveyor belt (net #90) with the pique knit fabric facing downwards, and passed through a high-pressure water jet device A. A high-pressure water jet was applied from the synthetic paper A' side at a jet pressure of 0.1 MPa, and then passed through the high-pressure water jet device A again, with a high-pressure water jet applied from the synthetic paper A' side at a jet pressure of 3 MPa. Next, it was passed through a high-pressure water jet device B, with a high-pressure water jet applied at a jet pressure of 4 MPa, and then passed through the high-pressure water jet device B again, with a high-pressure water jet applied at a jet pressure of 4 MPa. After that, it was passed through a high-pressure water jet device A, with a high-pressure water jet applied at a jet pressure of 2 MPa, and then passed through the high-pressure water jet device A again, with a high-pressure water jet applied at a jet pressure of 4 MPa. Furthermore, the water was passed through high-pressure water jet device B to apply a high-pressure water flow at a jetting pressure of 4 MPa, and then again through high-pressure water jet device B to apply a high-pressure water flow at a jetting pressure of 4 MPa. Thereafter, the laminate was inverted, and the synthetic fiber paper B prepared on the moiré knitting side was laminated. Then, it was passed through the high-pressure water jet device A, and a high-pressure water flow was applied from the synthetic fiber paper B side at a jet pressure of 2 MPa. Subsequently, it was passed through the high-pressure water jet device A again, and a high-pressure water flow was applied at a jet pressure of 4 MPa. Further, the laminate was inverted and passed through the high-pressure water jet device B, and a high-pressure water flow was applied from the synthetic fiber paper A' side at a jet pressure of 7 MPa. Subsequently, it was passed through the high-pressure water jet device B again, and a high-pressure water flow was applied at a jet pressure of 8 MPa. Thereafter, the laminate was inverted once again and passed through the high-pressure water jet device B, and a high-pressure water flow was applied from the synthetic fiber paper B side at a jet pressure of 8 MPa. Furthermore, a high-pressure water flow was applied at a jet pressure of 10 MPa by passing it through the high-pressure water jet device B. Finally, after squeezing out the water derived from the high-pressure water flow, it was heated at 145 °C for 120 seconds to remove the moisture, and a water flow-interlaced non-woven fabric was obtained.

[0019] Example 3 The laminate prepared by laminating the prepared synthetic fiber paper A' and the prepared moiré knitting was placed on a conveyor belt (net #90) with the moiré knitting facing downwards, and a high-pressure water flow was applied from the synthetic fiber paper A' side at a jet pressure of 3 MPa by passing it through the high-pressure water jet device A. Next, it was passed through the high-pressure water jet device B, and a high-pressure water flow was applied from the synthetic fiber paper A' side at a jet pressure of ¼ MPa. Furthermore, it was passed through the high-pressure water jet device B again, and a high-pressure water flow was applied at a jet pressure of 4 MPa. Subsequently, it was passed through the high-pressure water jet device B, and a high-pressure water flow was applied at a jet pressure of 7 MPa. Furthermore, it was passed through the high-pressure water jet device B again, and a high-pressure water flow was applied at a jet pressure of 7 MPa. Thereafter, the laminate was inverted, and the synthetic fiber paper B prepared on the moiré knitting side was laminated. Then, it was passed through the high-pressure water jet device A, and a high-pressure water flow was applied from the synthetic fiber paper B side at a jet pressure of 3 MPa. Subsequently, it was passed through the high-pressure water jet device A again, and a high-pressure water flow was applied at a jet pressure of 4 MPa. Further, the laminate was inverted and passed through the high-pressure water jet device D, and a high-pressure water flow was applied from the synthetic fiber paper A' side at a jet pressure of 5 MPa. Subsequently, it was passed through the high-pressure water jet device D again, and a high-pressure water flow was applied at a jet pressure of 6 MPa. Thereafter, the laminate was inverted once again and passed through the high-pressure water jet device B, and a high-pressure water flow was applied from the synthetic fiber paper B side at a jet pressure of <5> MPa. Furthermore, a high-pressure water flow was applied at a jet pressure of 4 MPa by passing it through the high-pressure water jet device D. Finally, after squeezing the water from the high-pressure water stream, it was heated at 145°C for 120 seconds to remove moisture, obtaining a water-stream-interlaced nonwoven fabric.

[0020] The water-stream-interlaced nonwoven fabrics obtained in Examples 1 to 3 had inconspicuous water-stream traces and were homogeneous, and were suitably used as the base fabric of artificial leather.

Brief Description of the Drawings

[0021] [Figure 1] It is an organizational chart showing an example of the knitting structure of the fawn knitting used in the present invention.

Explanation of Reference Numerals

[0022] 1 Tack 2 Loop A plurality of courses in which only 10 loops exist 11 The first course in which tacks and loops alternately exist in the course direction 12 The second course in which loops and tacks alternately exist in the course direction

Claims

1. A method for producing a water-flow entangled nonwoven fabric, comprising applying a water flow to a laminate formed by laminating paper composed of ultrafine short fibers and a pique knit fabric composed of yarn, thereby entangling the ultrafine short fibers with each other and the pique knit fabric with each other. Note Piqué knit: A knit fabric consisting of multiple courses with only loops, and on both sides of the wale direction of these courses, there is a first course with alternating tucks and loops in the course direction and a second course with alternating loops and tucks in the course direction, wherein the positions of the tucks and loops in the first and second courses are offset in the weft.

2. A method for producing a water-entangled nonwoven fabric according to claim 1, wherein the paper is paper grain.

3. A method for producing a water-entangled nonwoven fabric according to claim 1, wherein the paper is synthetic fiber paper.

4. A method for producing a water-entangled nonwoven fabric according to claim 3, wherein the ultrafine short fibers constituting the synthetic paper are bonded together with a water-soluble binder.

5. A method for producing a water-entangled nonwoven fabric according to claim 1, wherein the yarn constituting the pique knit fabric is a multifilament yarn.

6. A method for producing a water-entangled nonwoven fabric according to claim 1, wherein the yarn constituting the pique knit fabric consists of S-twisted multifilament yarn and Z-twisted multifilament yarn.

7. A method for producing a water-entangled nonwoven fabric according to claim 1, using a pique knit fabric having three courses.

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