Papermaking felt and its manufacturing method

Abstract

To provide a papermaking felt which has little shedding of a batt fiber layer, is excellent in strength, and exhibits heat resistance without using expensive materials. A papermaking felt includes a batt fiber layer and a lattice network on only one side of a base fabric.

Description

[Technical Field]

[0001] The present invention relates to a papermaking felt and a method for producing the same. [Background technology]

[0002] A papermaking machine that removes moisture from paper raw materials generally comprises a wire part, a press part, and a dryer part. These wire part, press part, and dryer part are arranged in this order along the direction in which the wet paper is transported. The wet paper has a certain width in the cross-machine direction (CD) of the papermaking machine and moves in a strip-like shape in the machine direction (MD), which is perpendicular to the CD, through the papermaking machine. The wet paper is conveyed and squeezed out of the paper while being passed on to the papermaking tools attached to the wire part, press part, and dryer part, respectively, and is finally dried in the dryer part. Each of these parts uses papermaking tools corresponding to the respective functions of dewatering the wet paper (wire part), squeezing water (press part), and drying (dryer part).

[0003] In the dryer section, the conveyed wet paper is treated at high temperatures to remove the moisture remaining after squeezing in the press section. In the dryer section, both the wet paper and the papermaking felt are exposed to a high-temperature environment. For this reason, papermaking felts, especially those used in the dryer section, are required to have high heat resistance. Papermaking felts used in the dryer section are broadly divided into papermaking felts (woven canvas) with a woven surface, and papermaking felts (needle canvas) in which a batt fiber layer is bonded to the surface of a woven base fabric by needling or other means. In the case of needle canvas, the base fabric and batt fiber layer, which are the constituent materials, are required to have high heat resistance.

[0004] As a means for improving the heat resistance of papermaking felt, Patent Documents 1 and 2 describe the use of an acrylic base fabric. Furthermore, Patent Documents 3 and 4 describe that the heat resistance of papermaking felt can be improved by using fibers that are considered to be extremely heat-resistant, such as aramid fibers or polybenzoxazole fibers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-137395 [Patent Document 2] Japanese Patent Application Publication No. 8-81895 [Patent Document 3] Japanese Patent Application Publication No. 11-292233 [Patent Document 4] Japanese Utility Model Application Publication No. 5-10320 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the acrylic fibers described in Patent Documents 1 and 2 have low strength, and when used in a batt fiber layer, there is a problem of hair loss during needling. Also, the aramid fibers and polybenzoxazole fibers described in Patent Documents 3 and 4 are expensive, which increases the manufacturing cost of papermaking felt.

[0007] In view of the above circumstances, an object of the present invention is to provide a papermaking felt which has little shedding of the batt fiber layer, is excellent in strength, and exhibits heat resistance without using expensive materials. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above problems can be solved by specifying the structure of the papermaking felt, and have thus completed the present invention.

[0009] That is, the present invention relates to the following. [1] A papermaking felt comprising a batt fiber layer and a lattice network on only one side of a base fabric. [2] The papermaking felt according to [1], wherein the lattice network is disposed between the base fabric and the batt fiber layer. [3] The papermaking felt according to [1] or [2], wherein the batt fiber layer contains at least one type of fiber selected from the group consisting of acrylic fiber, nylon fiber, polyester fiber, aramid fiber, carbon fiber, polyparaphenylene benzobisoxazole fiber, polyimide fiber, fluorine fiber, glass fiber, and polyphenylene sulfide fiber. [4] The papermaking felt according to [3], wherein the batt fiber layer contains acrylic fibers. [5] The papermaking felt according to [4], wherein the content of the acrylic fibers in the entire batt fiber layer is 50% by mass or more. [6] The papermaking felt according to any one of [1] to [5], wherein the constituent material of the fibers constituting the yarns used for the base fabric contains at least one resin selected from the group consisting of polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, polyester resin, polyamide resin, acetal resin, and polycarbonate resin. [7] The papermaking felt according to [6], wherein the constituent material of the fibers constituting the yarns used in the base fabric contains polyester resin.

[0010] [8] The papermaking felt according to any one of [1] to [7], wherein the MD yarns and / or CD yarns constituting the lattice network include spun yarns. [9] The papermaking felt according to any one of [1] to [8], wherein the structure of the lattice network is a structure in which CD yarns are sandwiched between MD yarns arranged above and below.

[10] The papermaking felt according to any one of [1] to [9], wherein the material that binds the threads that make up the lattice network is an adhesive.

[11] The papermaking felt according to

[10] , wherein the adhesive for bonding the threads constituting the lattice network contains a polyvinyl alcohol-based resin.

[12] The papermaking felt according to any one of [1] to

[11] , wherein the yarn density of the MD yarns constituting the lattice network is at least five times the yarn density of the CD yarns.

[13] The mesh weight of the lattice structure is 200 g / cm 2 The papermaking felt according to any one of [1] to

[12] below.

[0011]

[14] A method for producing a papermaking felt according to any one of [1] to

[13] , comprising a step of stacking a first fabric including the lattice network body and a second fabric including the base fabric, and then needling the stacked fabric.

[15] laminating the batt fiber layer and the lattice mesh body and then needling them to form a first fabric; and a step of stacking a second fabric including the base fabric and the first fabric in this order so that the batt fiber layer included in the first fabric is located on the opposite side of the lattice mesh from the base fabric, and then needling the stacked fabric.

[14] A method for producing a papermaking felt according to

[14] . [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a papermaking felt which does not use expensive materials, has little shedding of the batt fiber layer, is excellent in strength, and exhibits heat resistance without using expensive materials. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram schematically showing a papermaking felt according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically showing a papermaking felt according to an embodiment of the present invention. [Figure 3]FIG. 3 is a diagram schematically showing a papermaking felt according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram schematically showing a papermaking felt according to an embodiment of the present invention. [Figure 5] FIG. 5 is a diagram schematically showing a papermaking felt according to an embodiment of the present invention. [Figure 6] FIG. 6 is a diagram schematically showing a papermaking felt according to an embodiment of the present invention. [Figure 7] FIG. 7 is a diagram schematically showing a papermaking felt of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the papermaking felt and the method for producing the same of the present invention will be described, but the present invention is not limited to these. In addition, in this specification, the term "A to B" indicating a range of numerical values ​​means a range including A and B, and indicates "not less than A and not more than B."

[0015] <Papermaking felt> Hereinafter, the papermaking felt according to the embodiment of the present invention will be described in detail, with reference to the drawings as necessary. Note that the embodiment shown in Figures 1 to 6 is one embodiment of the papermaking felt according to the embodiment of the present invention, and the present invention is not limited to this.

[0016] A papermaking felt according to an embodiment of the present invention includes a batt fiber layer and a lattice network on only one side of a base fabric. In one embodiment, the papermaking felt 1 shown in Fig. 1 is formed by laminating, in order from a base fabric 30, two batt fiber layers 10, one lattice network layer 20, and three batt fiber layers 10.

[0017] There is no particular limitation on the thickness of the papermaking felt, but from the viewpoint of resistance to shedding and prevention of paper defects, it is preferably 3.5 to 6.1 mm, more preferably 4.0 to 5.6 mm, and even more preferably 4.5 to 5.1 mm.

[0018] There is no particular restriction on the basis weight of papermaking felt, but from the viewpoint of resistance to shedding and prevention of paper defects, it is recommended to use a weight of 1100 to 2300 g / cm 2 It is preferable that the density is 1300 to 2100 g / cm 2 More preferably, it is 1500 to 1900 g / cm 2 It is more preferable that:

[0019] The construction of the papermaking felt will be described in detail below.

[0020] [Lattice network] The papermaking felt according to the embodiment of the present invention includes a lattice mesh. In this specification, the lattice mesh refers to a mesh material in which substantially linear fibrous materials are aligned and laminated biaxially (vertical and horizontal) or triaxially (vertical, horizontal, and diagonal). Examples of such lattice mesh materials include those sold under the trade names "CLENET" (manufactured by Kurabo Industries Co., Ltd.), "SOF" (manufactured by Sumika Sekisui Film Co., Ltd.), "Warif" (manufactured by ENEOS Techno Material Corporation), and "CONWEDNET" (manufactured by ENEOS Techno Material Corporation).

[0021] By including a lattice network in the papermaking felt according to the embodiment of the present invention, it is possible to reduce the number of times the base fabric is needled during the manufacture of the papermaking felt. Furthermore, the batt fiber layer is more entangled with the lattice network than with the base fabric (structural effect), which improves the adhesion of the batt fiber layer. This effect is more pronounced by including the lattice network above the base fabric (in the stacking direction) (distance effect). As a result, damage to the base fabric is prevented, and a heat-resistant papermaking felt with less shedding of the batt fiber layer can be provided. In other words, the cost of the papermaking felt can be reduced because there is a wider range of options for the base fabric material without using expensive materials. In this specification, the "number of times of needling to the base fabric" refers to the total number of times of needling when forming the second fabric and when entangling and integrating the second fabric and the first fabric in the manufacturing method of papermaking felt described later. The first fabric and the second fabric will be described later.

[0022] There are no particular restrictions on the number of lattice mesh bodies (hereinafter also referred to as "number of sheets"), but from the viewpoint of breathability (drying property), it is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 to 2. When the number of sheets is 2 or more, a layer other than the lattice mesh body (such as a batt fiber layer) may be included between one lattice mesh body and another lattice mesh body, but it is preferable to use the lattice mesh bodies in layers.

[0023] A lattice network is typically composed of MD-direction yarns (hereinafter also referred to as "MD yarns") and CD-direction yarns (hereinafter also referred to as "CD yarns"), and has a biaxially orthogonal network structure in which these yarns are bonded.

[0024] Although there are no particular limitations on the MD yarns and / or CD yarns that make up the lattice network, from the viewpoint of shedding resistance, spun yarns, multifilament, or bulky yarns are preferred, and spun yarns are more preferred. Of these, nylon spun yarns and acrylic spun yarns are preferred for the MD yarns, and tetron spun yarns and acrylic spun yarns are preferred for the CD yarns.

[0025] There are no particular restrictions on the thread density of the MD yarns that make up the lattice network, but from the viewpoints of shedding resistance and breathability (dryness), it is preferably 3 to 9 threads / cm, more preferably 4 to 8 threads / cm, and even more preferably 5 to 7 threads / cm.

[0026] There are no particular restrictions on the thread density of the CD yarns that make up the lattice network, but from the viewpoints of shedding resistance and breathability (dryness), it is preferably 1 to 4 yarns / cm, more preferably 1 to 3 yarns / cm, and even more preferably 1 to 2 yarns / cm.

[0027] There are no particular restrictions on the relationship between the yarn density of the MD yarns and the yarn density of the CD yarns that make up the lattice network, but from the viewpoint of breathability (dryability), the yarn density of the MD yarns is preferably at least 5 times the yarn density of the CD yarns, more preferably at least 6 times, and even more preferably at least 8 times. There is no particular upper limit, but it can be, for example, 12 times or less, 11 times or less, or 10 times or less.

[0028] There are no particular restrictions on the structure of the lattice mesh, but from the standpoint of shedding resistance and breathability (dryness), a structure in which CD yarns are sandwiched between MD yarns arranged above and below is preferred, and a structure in which CD yarns are sandwiched between MD yarns arranged alternately above and below is more preferred.

[0029] There are no particular restrictions on the method for joining the MD and CD yarns that make up the lattice network, but from the standpoint of hair loss resistance, adhesive bonding, welding, heat treatment, stitching, sewing, or ultrasonic welding are preferred, and adhesive bonding is more preferred. In one embodiment, the material that binds the threads that make up the lattice network can be an adhesive.

[0030] There are no particular restrictions on the adhesive that bonds the MD and CD yarns that make up the lattice network, but from the standpoint of hair loss resistance, it is preferable that the adhesive contains at least one selected from the group consisting of polyvinyl alcohol-based resins, polyurethane-based resins, and polyolefin-based resins, and it is more preferable that the adhesive contains polyvinyl alcohol-based resins.

[0031] There are no particular restrictions on the thickness of the lattice mesh, but from the viewpoint of resistance to shedding and prevention of paper defects, it is preferably 0.3 to 0.9 mm, more preferably 0.4 to 0.8 mm, and even more preferably 0.5 to 0.7 mm.

[0032] There is no particular restriction on the basis weight of the lattice mesh, but from the viewpoint of resistance to shedding and prevention of paper defects, it is recommended to use a weight of 10 g / cm 2 It is preferable that the density is 20 g / cm or more. 2 More preferably, it is 30 g / cm or more. 2 It is more preferable that the density is 200 g / cm or more. 2 Preferably, it is 150 g / cm or less. 2 More preferably, it is 100 g / cm or less. 2 In one embodiment, the basis weight of the lattice mesh body is 10 to 200 g / cm 2 , 20~150g / cm 2 , or 30 to 100 g / cm 2 It can be said that:

[0033] [Bat fiber layer] A papermaking felt according to an embodiment of the present invention includes a batt fiber layer. The batt fiber layer is a layer made of batt fibers. More specifically, the batt fiber layer is a fiber assembly layer formed by entangling batt fibers, and in one embodiment, functions as a layer having thermal conductivity, surface smoothness, and the like.

[0034] Examples of the batt fiber layer include a batt fiber layer containing at least one fiber selected from the group consisting of acrylic fiber, nylon fiber, polyester fiber, aramid fiber, carbon fiber, polyparaphenylene benzobisoxazole fiber, polyimide fiber, fluorine fiber, glass fiber, and polyphenylene sulfide fiber. Among these, from the viewpoints of heat resistance and cost reduction, it is more preferable to contain at least one fiber selected from the group consisting of acrylic fiber and nylon fiber, and it is even more preferable to contain acrylic fiber. From the viewpoint of surface smoothness, it is preferable that these fibers be short fibers. From the viewpoint of environmental conservation and the health and safety of workers, it is preferable that the batt fiber layer does not contain inorganic materials such as glass fibers.

[0035] When the batt fiber layer contains acrylic fibers, the acrylic fiber content of the entire batt fiber layer is preferably 50% by mass or more, more preferably 55% by mass or more, and even more preferably 65% ​​by mass or more, from the viewpoint of heat resistance. There is no upper limit, but it can be, for example, 95% by mass or less, 90% by mass or less, or 85% by mass or less.

[0036] When multiple types of fibers are used to form the batt fiber layer, there are no particular limitations on the content or content ratio of each fiber to the total fibers (hereinafter also referred to as "batt ratio"). When two types of fibers are used to form the batt fiber layer, from the viewpoints of heat resistance and defibration of the batt fibers during the production of papermaking felt, the batt ratio of the fibers with a higher content to the fibers with a lower content is preferably 99:1 to 50:50, more preferably 85:15 to 50:50, even more preferably 75:25 to 50:50, particularly preferably 70:30 to 50:50, and most preferably 60:40 to 50:50, When three or more types of fibers are used to form the batt fiber layer, from the viewpoints of heat resistance and defibration of the batt fibers during papermaking felt production, the content of the fiber with the largest content is preferably 99% by mass or less, more preferably 85% by mass or less, even more preferably 75% by mass or less, particularly preferably 70% by mass or less, and most preferably 60% by mass or less. In such cases, the lower limit of the content of the fiber with the largest content is preferably more than 50% by mass.

[0037] The batt fiber layer may be included on only one side of the base fabric of the papermaking felt together with the lattice mesh. From the viewpoint of surface smoothness, it is preferable that the batt fiber layer be positioned so that the lattice mesh is included between the base fabric and the batt fiber layer.

[0038] (Bat fiber layer located on the opposite side of the grid mesh from the base fabric) From the viewpoint of surface smoothness, it is preferable that the batt fiber layer is at least located on the opposite side of the lattice mesh from the base fabric. When a batt fiber layer is present on the opposite side of the lattice mesh from the base fabric (hereinafter also referred to as the "batt fiber layer on the opposite side of the base fabric"), there may be only one layer or two or more layers.

[0039] There are no particular restrictions on the number of batt fiber layers on the side opposite the base fabric, but from the viewpoint of shedding resistance, it is preferably 0 to 5, more preferably 1 to 4, even more preferably 1 to 3, and particularly preferably 2 to 3. When there are two or more batt fiber layers on the side opposite the base fabric, it is preferable that all of the layers satisfy the fiber length, fineness, basis weight, and thickness described below.

[0040] There are no particular restrictions on the fiber length of the batt fibers constituting the batt fiber layer on the side opposite the base fabric, but from the viewpoints of shedding resistance and surface smoothness, it is preferably 20 to 140 mm, more preferably 40 to 120 mm, and even more preferably 60 to 100 mm. When there are two or more batt fiber layers on the side opposite to the base fabric, the fiber lengths of the batt fibers constituting each batt fiber layer may be the same or different.

[0041] There are no particular restrictions on the fineness of the batt fibers that make up the batt fiber layer opposite the base fabric, but from the viewpoints of shedding resistance and surface smoothness, it is preferably 1 to 30 dtex, more preferably 3 to 24 dtex, and even more preferably 6 to 18 dtex. When the batt fiber layer is made up of two or more types of batt fibers, the average fineness of these fibers (hereinafter also referred to as the "average fineness") is preferably within the above range. The average fineness is calculated by adding up the fineness of each of the two or more types of fibers, weighted by the number of fibers, and dividing by the total number of fibers. For example, the average fineness of 10 batt fibers of 3 dtex and 5 batt fibers of 30 dtex can be calculated using the following formula: {(3×10)+(30×5)} / (10+5) When there are two or more batt fiber layers on the side opposite to the base fabric, the fineness of the batt fibers constituting each batt fiber layer may be the same or different. In addition, it is preferable that the fineness of the batt fibers in the layer closer to the surface is smaller, as this improves the breathability and surface smoothness of the papermaking felt.

[0042] There is no particular restriction on the basis weight of the batt fiber layer on the opposite side of the base fabric, but from the viewpoint of shedding resistance and breathability (drying property), the basis weight of at least one layer of the batt fiber layer should be 80 to 260 g / m 2 It is preferable that the thickness is 110 to 230 g / m 2 More preferably, it is 140 to 200 g / m 2 It is more preferable that: When two or more batt fiber layers are present on the side opposite to the base fabric, the basis weight of each batt fiber layer may be the same or different.

[0043] There are no particular restrictions on the thickness of the batt fiber layer on the side opposite to the base fabric, but from the viewpoint of shedding resistance and breathability (drying property), it is preferably 0.3 to 0.9 mm, more preferably 0.4 to 0.8 mm, and even more preferably 0.5 to 0.7 mm. When there are two or more batt fiber layers on the side opposite the base fabric, the thicknesses of the batt fiber layers may be the same or different.

[0044] (Bat fiber layer located on the base fabric side of the lattice mesh) The batt fiber layer may be located on the base fabric side of the lattice mesh. When a batt fiber layer is present on the fabric side of the lattice mesh (hereinafter also referred to as "batt fiber layer on the fabric side"), there may be only one or two or more.

[0045] There is no particular restriction on the number of batt fiber layers on the base fabric side, but from the viewpoint of shedding resistance, 0 to 5 is preferred, 1 to 4 is more preferred, 1 to 3 is even more preferred, and 2 to 3 is particularly preferred.

[0046] There are no particular restrictions on the total number of batt fiber layers on the side opposite the base fabric and the base fabric side (hereinafter also referred to as the "number of batt layers"), but from the viewpoints of shedding resistance, breathability (drying properties), and prevention of paper defects, it is preferably 1 to 10, more preferably 2 to 8, even more preferably 3 to 7, and particularly preferably 4 to 6.

[0047] The preferred ranges for the fiber length and fineness of the batt fibers constituting the batt fiber layer on the fabric side, as well as the basis weight and thickness of the batt fiber layer on the fabric side, are the same as those described for the batt fiber layer on the opposite side from the fabric side. Similarly, the closer to the surface, the smaller the batt fiber fineness is preferred.

[0048] [Base fabric] The end-shaped base fabric used in this embodiment is a base fabric having ends. The material of the fibers constituting the yarns used in the base fabric is preferably a thermoplastic resin having a heat resistance temperature of 100 to 250°C and a melting point of 160 to 300°C, more preferably containing at least one resin selected from the group consisting of polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, polyester resin, polyamide resin, acetal resin, and polycarbonate resin, and even more preferably containing a polyester resin. The fibers constituting the yarns used in the base fabric can be used as MD yarns and / or CD yarns.

[0049] The form of the fiber constituting the yarn used for the base fabric can be monofilament, multifilament, spun yarn, textured yarn that has been subjected to crimping, bulking, etc., bulky yarn, stretch yarn, or other processed yarn, or even twisted yarn obtained by twisting these yarns together. The cross-sectional shape of the fiber can be circular, approximately elliptical, polygonal, approximately star-shaped, approximately rectangular, or the like.

[0050] The fineness of the fibers constituting the yarn used for the base fabric is not particularly limited. When the yarn used for the base fabric is a monofilament, it can be preferably 89 to 2240 dtex (0.10 to 0.50 mm), more preferably 200 to 1440 dtex (0.15 to 0.40 mm). On the other hand, when the yarn used for the base fabric is a multifilament, the fineness of the monofilaments constituting this multifilament is usually 20 to 90 dtex (0.05 to 0.10 mm), preferably 40 to 60 dtex (0.07 to 0.08 mm). The number of fibers constituting the multifilament is usually 5 to 20, preferably 7 to 15. When these yarns are twisted together to form a twisted yarn, the number of these yarns is usually 2 to 15, preferably 3 to 10.

[0051] The threads constituting the base fabric may be of one type only, or may be of two or more types. The base fabric may have either a single weave structure or a multiple weave structure, and the weave structure is not particularly limited, and may be, for example, a plain weave, a twill weave, a satin weave, a variant weave, or any other weave, or a combination thereof.

[0052] The basis weight of the base fabric is not particularly limited, but is usually 400 to 1300 g / m 2 , preferably 500 to 1100 g / m 2 The thickness of the base fabric is not particularly limited, but is usually 0.4 to 2.0 mm, preferably 0.7 to 1.2 mm. The density of the base fabric is not particularly limited, but is usually 0.6 to 1.2 g / cm. 3 , preferably 0.7 to 1.1 g / cm 3 It can be said that:

[0053] [Other layers] The papermaking felt according to the embodiment of the present invention may include other layers in addition to the base fabric, batt fiber layer, and lattice network, such as a film layer, a paper layer, a sheet, a foam, etc. The papermaking felt according to the embodiment of the present invention preferably comprises only a base fabric, a batt fiber layer, and a lattice network.

[0054] [shape] The papermaking felt according to the embodiment of the present invention can be formed into various shapes depending on its application, for example, a flat plate shape, a belt shape, or a cylindrical shape.

[0055] [Application] The papermaking felt according to the embodiment of the present invention has little shedding of the batt fiber layer, is excellent in strength, and exhibits heat resistance without using expensive materials, and therefore can be suitably used, for example, as a papermaking felt for use in the dryer part of a papermaking machine.

[0056] <Manufacturing method for papermaking felt> A method for producing a papermaking felt according to an embodiment of the present invention includes a step of laminating a first fabric including a lattice network and a second fabric including a base fabric, and then needling the laminate. Furthermore, from the viewpoint of preventing damage to the base fabric, the method for manufacturing papermaking felt according to the embodiment of the present invention preferably includes, in this order, a step of laminating a batt fiber layer and a lattice mesh body and performing needling to form a first fabric, and a step of laminating a second fabric including a base fabric and the first fabric and performing needling so that the batt fiber layer included in the first fabric is located on the opposite side of the lattice mesh body from the base fabric.

[0057] In this specification, the term "first fabric" refers to a fabric containing a lattice mesh body used in the method for producing papermaking felt. The first fabric may be composed of only a lattice mesh body, or may be composed of a lattice mesh body and other layers such as a batt fiber layer. In this specification, the term "second fabric" refers to a fabric including a base fabric used in the method for producing papermaking felt. The second fabric may be composed of only the base fabric, or may be composed of other layers such as a batt fiber layer in addition to the base fabric.

[0058] The details and preferred aspects of the lattice network, batt fiber layer and base fabric used in the method for producing a papermaking felt according to the embodiment of the present invention are the same as those described above.

[0059] (First fabric forming method) In an embodiment of the present invention, when the first fabric is composed only of a lattice mesh body, the lattice mesh body can be used as the first fabric. When the first fabric includes another layer, such as a batt fiber layer, in addition to the lattice mesh body, the first fabric can be formed, for example, by laminating the other layer on the lattice mesh body and entangling them together by needling. When the first fabric includes two or more other layers, the first fabric can be formed by laminating another layer on the other layer entangled with the lattice mesh body, and then repeating needling.

[0060] (Second fabric forming method) In an embodiment of the present invention, when the second fabric is composed only of a base fabric, the base fabric can be used as the second fabric. When the second fabric includes other layers, such as a batt fiber layer, in addition to the base fabric, the second fabric can be formed, for example, by laminating the other layers on the base fabric and entangling them together by needling. When the second fabric includes two or more other layers, the second fabric can be formed by laminating additional layers on the other layers entangled together with the base fabric, and then repeating needling.

[0061] (Method for forming papermaking felt) When the first cloth includes a batt fiber layer, the papermaking felt according to the embodiment of the present invention can be formed by stacking the first cloth and a second cloth including a base fabric, and then needling the stacked layers so that the batt fiber layer included in the first cloth is located on the opposite side of the lattice network from the base fabric. When the papermaking felt contains layers other than the base fabric, the lattice network, and the batt fiber layer, the layers can be formed by known methods. However, when forming the layers, it is preferable to adopt a method or procedure that does not increase the number of needling operations on the base fabric.

[0062] In one embodiment, the papermaking felt 1 shown in FIG. 1 is produced by the following steps. In the first step, the batt fiber layer 10 and the lattice mesh body 20 are stacked and then needled to form the first fabric 40. More specifically, the first fabric 40 can be formed by stacking one batt fiber layer 10 on the lattice mesh body 20, and then entangling and integrating them by needling, and repeating this process three times. In the second step, a papermaking felt is formed by laminating the first fabric 40 and a second fabric 50 including the base fabric 30 so that the batt fiber layer 10 included in the first fabric 40 is located on the opposite side of the lattice network 20 from the base fabric 30, and then needling the laminate. More specifically, the second fabric 50 can be formed by laminating one batt fiber layer 10 on the base fabric 30, and then entangling and integrating the layers by needling, and repeating this process twice.

[0063] (Number of times needling the base fabric) In an embodiment of the present invention, the base fabric, the batt fiber layer, and the lattice mesh included in the papermaking felt are firmly integrated, and in order to reduce the shedding of the batt fiber layer, the number of needling operations for the base fabric is set to 25 times / cm. 2 More than 35 times / cm is preferable. 2 More preferably, 45 times / cm or more 2 The above is even more preferable. In order to prevent damage to the base fabric and maintain the heat resistance of the papermaking felt, the number of needling operations to the base fabric should be 75 times / cm. 2 Preferably less than 65 times / cm 2 Less than 55 times / cm is more preferable. 2 The following is even more preferred: In one embodiment, the number of needling times to the base fabric is 45 to 55 times / cm 2 It can be said that: [Example]

[0064] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0065] [Manufacturing papermaking felt] Example 1 (Formation of the first cloth) Acrylic staple fibers and nylon staple fibers were blended in a mass ratio of 75:25 and carded to form a fiber web, resulting in a batt fiber layer with an average fineness of 11 dtex. One of the formed batt fiber layers was layered on the lattice mesh, and then entangled and integrated by needling. This process was repeated three times to form a first fabric. The lattice mesh was made of a biaxial orthogonal net (trade name "Kurenet NT6110" (Kurabo Industries, Ltd.)) in which nylon spun yarns were used for the MD yarns and Tetron spun yarns for the CD yarns, which were bonded with a polyvinyl alcohol resin. The yarn density of the MD yarns used in the lattice mesh was 6.0 threads / cm, and the yarn density of the CD yarns was 1.0 threads / cm. The thickness of the lattice mesh was 0.6 mm, and the basis weight was 50 g / m. 2It was. The batt fiber layer formed on the lattice mesh has a thickness of 0.6 mm and a basis weight of 150 g / m 2 It was.

[0066] (Formation of the second cloth) A double-woven base fabric was obtained by weaving polyester monofilament yarns for the MD and CD yarns on a loom. One layer of the batt fiber layer formed above was laid on top of the base fabric, and then the two layers were entangled and integrated by needling. This process was repeated twice to form a second fabric. The number of needling cycles was 20 times / cm. 2 was treated as. The base fabric is 0.9 mm thick and has a basis weight of 800 g / m 2 It was. The batt fiber layer formed on the base fabric has a thickness of 0.6 mm and a basis weight of 150 g / m 2 It was.

[0067] (Production of papermaking felt) The first fabric was layered on the batt fiber layer of the second fabric so that the batt fiber layer contained in the first fabric was located on the opposite side of the lattice network to the base fabric, and the two fabrics were entangled and integrated by needling to obtain the papermaking felt of Example 1. The number of needling cycles was 30 times / cm. 2 was treated as.

[0068] The construction of the papermaking felt of Example 1 was as follows. This papermaking felt had the structure shown in Fig. 1. The thickness of the papermaking felt was 4.5 mm and the basis weight was 1600 g / m 2 It was. Base fabric (polyester monofilament, thickness 0.9mm) / batt fiber layer (acrylic fiber and nylon fiber 75:25 blend, thickness 0.6mm) / batt fiber layer (acrylic fiber and nylon fiber 75:25 blend, thickness 0.6mm) / lattice mesh (nylon spun yarn and Tetoron spun yarn, thickness 0.6mm) / batt fiber layer (acrylic fiber and nylon fiber 75:25 blend, thickness 0.6mm) / batt fiber layer (acrylic fiber and nylon fiber 75:25 blend, thickness 0.6mm) / batt fiber layer (acrylic fiber and nylon fiber 75:25 blend, thickness 0.6mm) (outermost layer in the stacking direction)

[0069] <Examples 2 to 5> The papermaking felts of Examples 2 to 5 were obtained in the same manner as in Example 1, except that the number of batt fiber layers in the first and second cloths was kept at five in total, and the number of each was changed as shown in Table 1. The papermaking felts of Examples 2 to 5 have the structures shown schematically in Figures 2 to 5, respectively. The papermaking felts of Examples 2 to 5 all have a thickness of 4.5 mm and a basis weight of 1600 g / m 2 It was.

[0070] In Example 4, the second fabric did not have a batt fiber layer and was formed only from a base fabric. Therefore, needling was not required when forming the second fabric. Therefore, the number of needling operations when entangling and integrating the second fabric and the first fabric was 30 times / cm. 2 was defined as the number of times the base fabric was needled.

[0071] Furthermore, the first cloth in Example 5 did not have a batt fiber layer, and was formed only from a lattice mesh body. Therefore, needling was not required when forming the first cloth. One batt fiber layer similar to that in Example 1 was laminated on the base cloth, and then entangled and integrated by needling. This was repeated four times in total. Furthermore, one batt fiber layer and the lattice mesh body were laminated so that the lattice mesh body forming the first cloth was located on the opposite side of the base cloth, and then entangled and integrated by needling, thereby obtaining the papermaking felt of Example 5. The number of needlings was 50 times / cm. 2 was treated as.

[0072] <Examples 6 to 8> The papermaking felts of Examples 6 to 8 were obtained in the same manner as in Example 1, except that the mass ratio (batt ratio) of the acrylic staple fiber to the nylon staple fiber in the batt fiber layers contained in the first cloth and the second cloth was changed as shown in Table 1. The papermaking felts of Examples 6 to 8 all had the structure shown schematically in Figure 1. The papermaking felts of Examples 6 to 8 all had a thickness of 4.5 mm and a basis weight of 1600 g / m 2 It was.

[0073] Example 9 The papermaking felt of Example 9 was obtained in the same manner as in Example 1, except that two layers of the lattice network were used. The papermaking felt of Example 9 has the structure shown schematically in Figure 6. The papermaking felt of Example 9 has a thickness of 5.1 mm and a basis weight of 1650 g / m 2 It was.

[0074] <Comparative Example 1> (Production of papermaking felt) Acrylic staple fibers and nylon staple fibers were blended in a mass ratio of 75:25 and carded to form a fiber web, resulting in a batt fiber layer with an average fineness of 11 dtex. A double-woven base fabric was obtained by weaving polyester monofilament yarns for the MD and CD yarns on a loom. One layer of the batt fiber layer formed above was laid on top of the base fabric, and then the two layers were entangled and integrated by needling. This process was repeated five times to form a second fabric. Here, the thickness of the base fabric is 0.9 mm and the weight is 800 g / m 2 The number of needling was 50 times / cm 2 The resulting second fabric was used as the papermaking felt of Comparative Example 1. The papermaking felt of Comparative Example 1 has a structure as shown in FIG. 7. The papermaking felt of Comparative Example 1 has a thickness of 3.9 mm and a basis weight of 1550 g / m 2 It was.

[0075] <Comparative Example 2> The papermaking felt of Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that nylon monofilaments were used for the MD and CD yarns and woven on a loom to obtain a double-woven base fabric. The papermaking felt of Comparative Example 2 has a structure as shown schematically in Figure 7. The papermaking felt of Comparative Example 2 has a thickness of 3.9 mm and a basis weight of 1550 g / m 2 It was.

[0076] <Comparative Example 3> A papermaking felt of Comparative Example 3 was obtained in the same manner as Comparative Example 1, except that the mass ratio (batt ratio) of the acrylic staple fibers to the nylon staple fibers in the batt fiber layer was changed to 0:100. The papermaking felt of Comparative Example 3 has a structure as schematically shown in Figure 7. The papermaking felt of Comparative Example 3 has a thickness of 3.9 mm and a basis weight of 1550 g / m 2 It was.

[0077] <Comparative Example 4> A papermaking felt of Comparative Example 4 was obtained in the same manner as in Comparative Example 2, except that the mass ratio (batt ratio) of the acrylic staple fibers to the nylon staple fibers in the batt fiber layer was changed to 0:100. The papermaking felt of Comparative Example 4 has a structure as schematically shown in Figure 7. The papermaking felt of Comparative Example 4 has a thickness of 3.9 mm and a basis weight of 1550 g / m 2 It was.

[0078] <Comparative Example 5> The number of needlings (number of needlings into the base fabric) when forming the second fabric is 80 times / cm 2 The papermaking felt of Comparative Example 5 was obtained in the same manner as in Comparative Example 1, except that the thickness was changed to 3.9 mm and the weight per unit area was changed to 1550 g / m. 2 It was.

[0079] [Evaluation of batt fiber layers and papermaking felts] The papermaking felts of Examples 1 to 9 and Comparative Examples 1 to 5 were evaluated as follows. The results are shown in Table 1.

[0080] <Hair removal from the batt fiber layer> The delamination of the batt fiber layer was evaluated using a Gakushin-type friction and abrasion tester based on JIS L 0849 (2013). Specifically, a papermaking felt test piece was placed on the test piece platform, and waterproof abrasive paper (C-P320 as specified in JIS R 6253 (2022)) was placed on top of it. After reciprocating motion, the amount of abrasion (mg)—the amount of fibers that had fallen off from the papermaking felt test piece—was measured and used to evaluate delamination. The test conditions were as follows: (Test conditions for papermaking felt) Sliding speed: 30 times / min Sliding distance: 100mm Number of slides: 400 Wear terminal dimensions: 20 x 20 mm ·Wear terminal weight: 500g Water-resistant abrasive paper grit: 320 mesh

[0081] The papermaking felt was heated (exposed to dry heat) under the following conditions, and the depilling of the batt fiber layer after heating was evaluated. The test conditions were the same as those for the unheated papermaking felt test piece. (Heating conditions) ·Heating temperature: 180℃ (dry heat exposure) Cooking time: 20 hours Heating device: Product name: "High Temp Oven H-80" (manufactured by Asahi Scientific Co., Ltd.)

[0082] <Cutting strength of papermaking felt> The cutting strength was evaluated according to the following procedure. A papermaking felt was cut into a piece 30 cm long x 5 cm wide to obtain a papermaking felt test piece. The obtained papermaking felt test piece was pulled in the length direction under the following conditions, and the cutting strength (N / 5 cm) was measured. The cutting strength of the papermaking felt indicates the cutting strength of the base fabric. (Cutting strength measurement conditions) Test temperature: Room temperature Pulling speed: 200mm / min Measuring device: Product name "Autograph" (Shimadzu Corporation)

[0083] After heating (exposing to dry heat) the papermaking felt under the following conditions, it was cut into a piece 30 cm long x 5 cm wide to obtain a papermaking felt test piece after heating. The obtained papermaking felt test piece was pulled in the length direction and the breaking strength (N / 5cm) after heating was measured. The test conditions were the same as for the papermaking felt test piece that was not heated. (Heating conditions) ·Heating temperature: 180℃ (dry heat exposure) Cooking time: 20 hours Heating device: Product name: "High Temp Oven H-80" (manufactured by Asahi Scientific Co., Ltd.)

[0084] [Table 1]

[0085] The results shown in Table 1 show that the papermaking felts of the Examples have less wear of the batt fiber layer both at new and after heating, and are less susceptible to shedding, compared to the papermaking felts of Comparative Examples 1 to 4. Furthermore, the papermaking felts of the Examples have greater cutting strength after heating, and the heat resistance of the base fabric is higher, compared to the papermaking felts of Comparative Examples 2 and 4. Furthermore, the papermaking felt of Comparative Example 5 had lower cutting strengths both new and after heating, although the wear amount of the batt fiber layer was almost the same as that of the papermaking felts of the Examples. This is thought to be because the number of needling cycles was increased to improve the adhesion of the batt fiber layer to the base fabric to the same level as that of the papermaking felts of the Examples, which damaged the base fabric and reduced the cutting strength. [Industrial Applicability]

[0086] The papermaking felt of the present invention has little shedding of the batt fiber layer, is excellent in strength, and exhibits heat resistance without using expensive materials, and therefore can be suitably used, for example, as a papermaking felt for use in the dryer part of a papermaking machine. [Explanation of symbols]

[0087] 1. Papermaking felt 10 batt fiber layer 20 Lattice network 30 Base fabric 40 First Cloth 50 Second Cloth

Claims

1. The batt fiber layer and the lattice mesh body are included on only one side of the end-shaped base fabric, A papermaking felt in which the yarn density of the MD yarns constituting the lattice network is at least five times the yarn density of the CD yarns.

2. 2. The papermaking felt according to claim 1, wherein the batt fiber layer contains at least one type of fiber selected from the group consisting of acrylic fiber, nylon fiber, polyester fiber, aramid fiber, carbon fiber, polyparaphenylene benzobisoxazole fiber, polyimide fiber, fluorine fiber, glass fiber, and polyphenylene sulfide fiber.

3. 3. A method for producing a papermaking felt according to claim 1, further comprising a step of stacking a first fabric including the lattice network body and a second fabric including the end-shaped base fabric, and then needling the stacked fabric.

4. laminating the batt fiber layer and the lattice mesh body and then needling them to form a first fabric; and a step of stacking a second fabric including the base fabric with ends and the first fabric in this order so that the batt fiber layer included in the first fabric is located on the opposite side of the lattice network from the base fabric with ends, and then needling the stacked fabric. A method for producing the papermaking felt according to claim 3.

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