Felt for papermaking and method for manufacturing the same

Abstract

The present invention provides a papermaking felt having good smoothness of a joint portion (no trace of a fusion portion, no base fabric trace) and an efficient production method thereof. A papermaking felt which is a papermaking felt in which at least one base fabric formed of a CD wire material in a felt running direction (MD direction) and a CD wire material in a cross direction of the felt (CD direction) and having an MD direction end portion region and a CD direction end portion region are at least one of a mutual overlapping portion between the MD direction end portion regions and a mutual overlapping portion between the CD direction end portion regions, the overlapping portion being fused without removing a part or all of the MD wire material or the CD wire material of the overlapping portion, wherein, when an average thickness of the fused portion in each base fabric is x (mm) and an average thickness before fusion is y (mm), a relationship of x and y of the at least one base fabric satisfies the following formula (1). 0.5 ≤ x / y ≤ 0.95 (1)

Description

Technical Field

[0001] This invention relates to felt for papermaking and its manufacturing method. Background Technology

[0002] Paper machines that remove moisture from paper raw materials generally consist of a wire section, a press section, and a drying section. These sections are arranged sequentially along the transport direction of the wet paper. The wet paper moves in a strip shape with a certain width within the paper machine in a direction perpendicular to the machine's travel direction (MD direction, machine direction) (CD direction, cross machine direction). It is conveyed and dehydrated by the papermaking equipment installed in the wire section, press section, and drying section, respectively, and is finally dried in the drying section.

[0003] The pressing unit configured in the press section has multiple pressing units connected in series along the conveying direction of the wet paper. Each pressing unit has an endless felt or an endless felt formed by connecting end-shaped felts on the paper machine, and a pair of rolls (i.e., roll press) or a cylindrical boot with an inner boot plate (i.e., boot press) arranged vertically and facing each other in such a way that a portion of the felt is sandwiched between them. For the wet paper that is transported by the felt moving in the same direction at approximately the same speed, the paper is pressed by the felt and the rollers and the cylindrical boot with the inner boot plate, and the moisture is continuously removed from the wet paper.

[0004] The required properties of felt used in press equipment include squeezeability, smoothness, and migration stability. Squeezability refers to the removal of moisture from wet paper. To achieve this property, it is important that the felt has good compression recovery characteristics; that is, when the felt is not under pressure, there are spaces (void volumes) within the felt for removing this moisture. When the felt is under pressure, the felt density reaches its maximum, the volume of these spaces decreases, and thus the moisture is released to the outside of the felt. Furthermore, it is also important to maintain this squeezeability throughout the use of the felt, and that the removed moisture does not return to the wet paper.

[0005] Smoothness refers to the smoothness of the wet paper surface and the felt surface (including the felt surface under pressure). The wet paper is pressed through the felt, thus the state of the felt surface is transferred to the wet paper surface. Therefore, in order to make the wet paper surface smooth, the surface of the felt (including the felt surface under pressure) must be smooth.

[0006] Migration stability refers to the stable migration of the endless felt disposed in the pressing device without breaking, shifting, twisting, vibrating, or undulating.

[0007] There are various types of paper, such as newspaper, book paper, cardboard, and household paper, and the papermaking machines used to manufacture these papers also come in various types. Currently, various types of papermaking felt are manufactured in conjunction with these papers and papermaking machines, but generally, this felt is formed by integrating a layer of nonwoven fiber material with a base fabric layer. The base fabric layer can be a woven fabric composed of, for example, monofilaments, monofilament yarns, multifilaments, or multifilament yarns. This fabric can be a single-layer product, a multi-layer product, or a laminated structure obtained by stacking these materials. The filaments are generally products obtained by extrusion molding of any synthetic polymer resin such as polyamide resin or polyester resin used for this purpose by those skilled in the art of papermaking equipment, animal fibers such as wool, and plant fibers such as cotton and linen.

[0008] The aforementioned base fabric layer can be made of various types of fabric, such as endless weaving (tube weaving) on ​​a loom, or sewing the ends of plain-woven end-shaped fabric together to form an endless shape, or joining the ends of two end-shaped fabrics in the mechanical cross-section or mechanical direction to form an endless shape.

[0009] The base fabric layer (paper felt) manufactured through tubular weaving has a seamless, continuous surface, resulting in excellent smoothness. However, various paper machines come in different sizes, so the corresponding base fabric layers need to be manufactured entirely custom-made. Therefore, to manufacture the base fabric layer through tubular weaving, every change in size requires minute adjustments to the loom settings, leading to very poor productivity and low yield.

[0010] In contrast, as a method for manufacturing efficient papermaking felt, a method has been proposed that involves overlapping the ends of the base fabric in the MD direction and pressing them together under the condition that the thickness of the overlapping portion substantially corresponds to that of the other portions (Patent Document 1). Specifically, a scheme is disclosed that, in order to make the thickness of the overlapping portion in the MD direction of the base fabric substantially correspond to that of the other portions, a method is used to remove the cross yarns from one side of the base fabric of the overlapping portion to reduce the cross yarn density.

[0011] Furthermore, as another method for manufacturing efficient papermaking felt, a method has been proposed that involves overlapping the ends of the base fabric in the CD direction and fusing them together under the condition that the thickness of the overlapping portion substantially corresponds to that of the other portions (Patent Document 2). Specifically, a scheme is disclosed in which the base fabric of a strip is rolled into a spiral shape, and in order to make the thickness of the overlapping portion in the MD direction of the base fabric substantially correspond to that of the other portions, the longitudinal yarn is removed from at least one of the base fabrics in the overlapping portion to form a fringe.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: Japanese Patent Publication No. 2006-510812

[0015] Patent Document 2: Japanese Patent Application Publication No. 10-226978 Summary of the Invention

[0016] The technical problem that the invention aims to solve

[0017] While the papermaking felt obtained by the manufacturing method disclosed in the prior art can be manufactured efficiently, the performance requirements, particularly smoothness, for papermaking felt are not entirely satisfactory. In particular, the welded portion, as disclosed in the prior art, lacks compressibility with the base layer. When manufacturing the base fabric under conditions where the welded portion and the base layer (including the non-welded portion around the welded portion) are of equal thickness, significant welded portion marks (base fabric marks) may appear under pressure when using the felt.

[0018] Therefore, the object of the present invention is to provide papermaking felt with good smoothness of the joint (without weld marks or base fabric marks) and an efficient manufacturing method thereof.

[0019] Technical solutions adopted to solve technical problems

[0020] After careful investigation, the inventors discovered that by making the thickness of the welded portion less than the thickness of the base portion, the thickness of the welded portion under pressure is equal to the thickness of the base portion (the thickness of the non-welded portion), thereby solving the problem of the present invention.

[0021] (1) A papermaking felt comprising at least one base fabric formed from CD wires in the felt transition direction (MD direction) and the felt cross-sectional direction (CD direction) and having MD-direction end regions formed by a first MD-direction end region and a second MD-direction end region and a CD-direction end region formed by the first CD-direction end region and the second CD-direction end region, wherein at least one of the MD-direction end regions and the CD-direction end regions overlaps with each other, without removing part or all of the MD wires or CD wires in the overlapping portion, wherein the overlapping portion is fused together.

[0022] When the average thickness of the welded portion in each base fabric is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y of at least one base fabric satisfies the following equation (1):

[0023] 0.5≤x / y≤0.95 (1).

[0024] (2) According to the papermaking felt described in (1), when the average thickness of the welded portion is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y of at least one base fabric satisfies the following equation (2):

[0025] 0.6≤x / y≤0.8 (2).

[0026] (3) The papermaking felt according to (1) or (2), wherein the first MD direction end region and the second MD direction end region of a base fabric overlap each other, and part or all of the overlapping CD wire is not removed, and the overlapping part is fused.

[0027] (4) The papermaking felt according to (1) or (2), wherein the first MD direction end regions and the second MD direction end regions of two or more base fabrics overlap each other, and part or all of the overlapping CD wire is not removed, and the overlapping portion is fused.

[0028] (5) The papermaking felt according to (1) or (2), wherein the end regions of the first MD direction and the end regions of the second MD direction of two or more base fabrics overlap with each other, and the end regions of the first CD direction and the end regions of the second CD direction do not remove part or all of the overlapping CD wire or MD wire, and the overlapping part is fused together.

[0029] (6) The papermaking felt according to (1) or (2), wherein the first CD direction end region and the second CD direction end region of a base fabric overlap each other, and part or all of the overlapping portion of the MD wire is not removed, and the overlapping portion is fused.

[0030] (7) The papermaking felt according to (1) or (2), wherein the first CD direction end regions and the second CD direction end regions of two or more base fabrics overlap each other, and part or all of the overlapping portion of the MD wire is not removed, and the overlapping portion is fused together.

[0031] (8) The papermaking felt according to any one of (1) to (7), wherein the overlap width (MD direction length) when the end regions in the MD direction overlap each other or the overlap width (CD direction length) when the end regions in the CD direction overlap each other is 1.0 mm to 3.0 mm.

[0032] (9) The papermaking felt according to any one of (1) to (8), wherein the weld width (length in the MD direction) when the overlapping portions of the end regions in the MD direction are welded together or the weld width (length in the CD direction) when the overlapping portions of the end regions in the CD direction are welded together is 1.0 mm to 5.0 mm.

[0033] (10) The papermaking felt according to any one of (1) to (9), wherein at least one of the MD wire or CD wire of the base fabric is a thermoplastic resin with a heat resistance temperature of 60°C to 200°C and a melting point of 80°C to 300°C.

[0034] (11) The papermaking felt according to any one of (1) to (10), wherein at least one base fabric has a unit area mass of 100 g / m². 2 ~500g / m 2 .

[0035] (12) A method for manufacturing papermaking felt, comprising:

[0036] (a) A process in which a base fabric formed by a CD wire in the felt moving direction (MD direction) and the felt transverse direction (CD direction) and having an MD direction end region formed by a first MD direction end region and a second MD direction end region and a CD direction end region formed by a first CD direction end region and a second CD direction end region overlaps with at least one of the MD direction end regions and the CD direction end regions.

[0037] (b) Without removing part or all of the overlapping MD or CD wires in step (a), the overlapping portions are completely welded together, and the overlapping end regions are joined together, such that when the average thickness of the welded portion in each base fabric is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y satisfies the following equation (1):

[0038] 0.5≤x / y≤0.95 (1);

[0039] (c) Repeat steps (a) and (b) as needed to form a ring shape that closes at least one piece of base fabric.

[0040] (13) The manufacturing method according to (12), wherein it includes:

[0041] In step (b), the overlapping end regions are joined together such that when the average thickness of the welded portion is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y satisfies the following equation (2):

[0042] 0.6≤x / y≤0.8 (2).

[0043] (14) A papermaking felt, wherein the felt is manufactured by the method described in (12) or (13).

[0044] The effects of the invention

[0045] The above structure provides papermaking felt with excellent smoothness at the joints (no weld marks or base fabric marks) and an efficient manufacturing method.

[0046] Brief description of the attached diagram

[0047] Figure 1 This is a schematic diagram of the base fabric of the present invention.

[0048] Figure 2 This is a schematic diagram of an article formed during the manufacturing process of the present invention, which is in the shape of a ring that encloses at least one base fabric.

[0049] Figure 3 This is a schematic diagram of an article formed during the manufacturing process of the present invention, which is in the shape of a ring that encloses at least one base fabric.

[0050] Figure 4 This is a schematic diagram illustrating the welding method of the present invention.

[0051] Figure 5 This is a schematic diagram showing the welding state of the base fabric of the present invention. Detailed Implementation

[0052] Hereinafter, embodiments of the papermaking felt base fabric and its manufacturing method according to the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to these examples.

[0053] Furthermore, unless otherwise defined herein, all technical and scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art. All patents, applications, and other publications (including information available on the Internet) referenced herein are incorporated herein by reference in their entirety.

[0054] The base fabric used for the papermaking felt of the present invention is formed by MD wires in the felt migration direction (MD direction) and CD wires in the felt cross-sectional direction (CD direction).

[0055] The MD / CD direction in the base fabric (with end-shaped structure) is as follows Figure 1 The arrows (MD / CD) indicate that when using papermaking felt in a papermaking machine, the MD direction is defined as the direction of felt movement (rotation), and the CD direction is defined as the direction of cross-sectional felt movement (rotation). The base fabric is as follows... Figure 1 The diagram shows an end region 1 in the first MD direction, an end region 2 in the second MD direction, an end region 3 in the first CD direction, an end region 4 in the second CD direction, and a central region 5 enclosed by the end regions in the first / second MD direction and the end regions in the first / second CD direction.

[0056] The papermaking felt of the present invention is

[0057] Papermaking felt formed by forming CD wires from the felt transition direction (MD direction) and the felt cross-sectional direction (CD direction) and having at least one base fabric having an MD direction end region formed by a first MD direction end region and a second MD direction end region and a CD direction end region formed by the first CD direction end region and the second CD direction end region, wherein at least one of the MD direction end regions and the CD direction end regions overlap each other, and the overlapping portion is welded together without removing part or all of the wires of at least one of the MD wires or CD wires of the overlapping portion, comprising base fabrics whose end regions are joined together according to the condition that the relationship between x and y of at least one base fabric satisfies the following formula (1) when the average thickness of the welded portion in each base fabric is set as x (mm) and the average thickness before welding is set as y (mm).

[0058] 0.5≤x / y≤0.95 (1)

[0059] Where x represents the average thickness of all welded portions of a base fabric, and y represents the average thickness of the base fabric before welding. For the papermaking felt of the present invention, when only one base fabric is used, the base fabric satisfies the relationship of the above formula (1). When multiple base fabrics are used, x / y is calculated for each base fabric separately, and at least one base fabric satisfies the relationship of the above formula (1).

[0060] The papermaking felt of the present invention is characterized in that the portion of the base fabric that is fused together with the end regions in the MD direction and / or the end regions in the CD direction is such that the average thickness of the fused portion is 50% or more and 95% or less, preferably 60% or more and 80% or less, of the average thickness before fusion, that is, it satisfies the above formula (1), and preferably satisfies the following formula (2).

[0061] 0.6≤x / y≤0.8 (2)

[0062] As a result, when using felt (under pressure), the thickness of the welded and unwelded portions is the same, the smoothness of the felt (without weld marks or base fabric marks) is improved, and consequently the smoothness of the paper is improved. This is because the compressibility of the welded portion is lower than that of the unwelded portion.

[0063] Furthermore, the papermaking felt of the present invention also includes a structure in which the overlapping portion of the MD wire or CD wire does not need to be removed. Therefore, this process is not required in this case, and the papermaking felt can be manufactured efficiently.

[0064] The papermaking felt of the present invention can be manufactured by joining one base fabric or by joining two or more base fabrics.

[0065] As specific examples of the papermaking felt of the present invention, the following forms (a) to (e) can be cited:

[0066] (a) The first MD direction end region and the second MD direction end region of a base fabric overlap each other, without removing part or all of the overlapping CD wire, and the overlapping part is fused to the papermaking felt.

[0067] (b) The first MD direction end regions and the second MD direction end regions of two or more base fabrics overlap each other, without removing part or all of the overlapping CD wire, and the overlapping part is fused to the papermaking felt.

[0068] (c) The end regions of the first MD direction and the end regions of the second MD direction of two or more base fabrics overlap with each other, and the end regions of the first CD direction and the end regions of the second CD direction do not remove part or all of the overlapping CD wire or MD wire, and the overlapping part is fused to the papermaking felt.

[0069] (d) The first CD direction end region and the second CD direction end region of a base fabric overlap each other, without removing part or all of the overlapping MD wire, and the overlapping part is fused to the papermaking felt.

[0070] (e) The first CD direction end regions and the second CD direction end regions of two or more base fabrics overlap each other, without removing part or all of the overlapping MD wire, and the overlapping part is fused to the papermaking felt.

[0071] In the case of manufacturing papermaking felt by joining together a single base fabric, for example Figure 2 As shown in (A), the first MD direction end region 1 and the second MD direction end region of the base fabric B can be overlapped and joined together.

[0072] In addition, such as Figure 3 As shown in (A), the base fabric can be rolled into a spiral shape, and the first CD direction end region 3 and the second CD direction end region 4 of the base fabric B can be overlapped and joined together.

[0073] When two or more base fabrics are joined together to manufacture papermaking felt, for example... Figure 2 As shown in (B), when three base fabrics B, B', and B” are joined together to manufacture papermaking felt, the second MD direction end region 2 of base fabric B and the first MD direction end region 1' of base fabric B', the second MD direction end region 2' of base fabric B' and the first MD direction end region 1” of base fabric B”, and the MD direction end region 2” of base fabric B” and the first MD direction end region 1 of base fabric B can be overlapped and joined together.

[0074] In addition, such as Figure 2 As shown in (C), when two base fabrics B and B' are joined together to manufacture papermaking felt, the first MD direction end region 1 and the second MD direction end region 2 of base fabric B can be overlapped and joined together, the first MD direction end region 1' and the second MD direction end region 2' of base fabric B' can be overlapped and joined together, and the first CD direction end region 3 of base fabric B and the second CD direction end region 4' of base fabric B' can be overlapped and joined together.

[0075] In addition, such as Figure 3 As shown in (B), when two base fabrics B and B' are rolled into a spiral shape and joined together to manufacture papermaking felt, the first CD direction end region 3 and the second CD direction end region 4 of base fabric B can be overlapped and joined together, the second MD direction end region 2 of base fabric B and the first MD direction end region 1' of base fabric B' can be overlapped and joined together, the first CD direction end region 3 of base fabric B and the second CD direction end region 4' of base fabric B' can be overlapped and joined together, and the first CD direction end region 3' of base fabric B' and the second CD direction end region 4' of base fabric B' can be overlapped and joined together.

[0076] When the ends in the MD direction or the CD direction are overlapped, the overlap width (when the ends in the MD direction are overlapped, it refers to the overlap length in the MD direction; when the ends in the CD direction are overlapped, it refers to the overlap length in the CD direction) is preferably 1.0 mm or more and 3.0 mm or less. The weld width (weld width) after joining (welding) is preferably 1.0 mm or more and 5.0 mm or less. If the overlap width is less than 1.0 mm, the weld width (weld width) will also be smaller depending on the joining conditions (welding conditions), and the strength after joining may not be sufficiently maintained. If the overlap width is greater than 3.0 mm, the weld width will be greater than 5.0 mm depending on the joining conditions (welding conditions), which may cause problems with surface smoothness (resulting in weld marks or base fabric marks).

[0077] In this specification, the term "joint" refers to the complete welding between overlapping MD-direction end regions and / or between overlapping CD-direction end regions, wherein the overlapping end regions are fixed to each other. Furthermore, it also includes a state where a portion of the welding material within the overlapping portion overflows outside the overlapping portion during welding, thus fixing the periphery of the overlapping portion as well; in this case, the weld width is greater than the overlap width.

[0078] The preferred constituent material for the fibers constituting MD and CD wires is a thermoplastic resin with a heat resistance temperature of 60°C to 200°C and a melting point of 80°C to 300°C. Examples of suitable materials include polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, polyethylene terephthalate, polyamide resin, acetal resin, and carbonate resin, with polyamide resin being the most preferred.

[0079] The fibers constituting MD and CD yarns can be monofilaments, multifilaments, short fiber yarns, or processed yarns such as textured yarns, bulked yarns, and stretch yarns that have undergone crimping, bulking, or other processing, as well as twisted yarns made by twisting these yarns together. The cross-sectional shape of the fibers can be circular, approximately elliptical, polygonal, approximately star-shaped, or approximately rectangular.

[0080] The fineness of the fibers constituting MD and CD yarns is not particularly limited. For monofilaments, a fineness of 89–2240 dtex (0.10–0.50 mm) is preferred, and 200–1440 dtex (0.15–0.40 mm) is even more desirable. For multifilaments, the fineness of the monofilaments constituting the multifilament is typically 20–90 dtex, preferably 40–60 dtex. The number of fibers constituting the multifilament is typically 5–20, preferably 7–15. Furthermore, when these yarns are twisted together to form twisted yarn, the number of these yarns is typically 2–15, preferably 3–10.

[0081] The MD and CD wires that make up the base fabric can be one type or two or more types.

[0082] The base fabric can be any single-layer or multi-layer weave, and the weaving structure is not particularly limited. It can be any of the following: plain weave, twill weave, satin weave, fancy weave, or combinations thereof.

[0083] There is no particular limitation on the unit area mass of the base fabric, which is usually set at 100-500 g / m². 2 The ideal value is 150–400 g / m³. 2 The thickness of the base fabric is not particularly limited, but is usually set at 0.4–1.3 mm, preferably 0.6–1.1 mm. The density of the base fabric is not particularly limited, but is usually set at 0.25–0.55 g / cm³. 3 The optimal value is 0.35–0.45 g / cm³. 3 The density of the base fabric is determined by dividing the mass per unit area of ​​the base fabric by the thickness of the base fabric. If the density is too low, the energy during welding will be difficult to transfer to the wire, which may lead to poor welding. If the density is too high, the energy during welding will be insufficient, which may also lead to poor welding.

[0084] There are no special restrictions on the size of the base fabric. The ends of the base fabric are overlapped and fused together, as long as the size can meet the size of the final product (paper felt).

[0085] There are no particular restrictions on the welding method for the base fabric, for example... Figure 4 As shown, it is preferable to use ultrasonic welding with a welding head 10 and an anvil 11. By arranging the overlapping portion of the base fabric between the welding head 10 and the anvil 11, ultrasonic waves are emitted from the welding head 10 to apply pressure to the welding head 10 toward the anvil 11, causing the base fabric to move in the direction along the overlapping portion, thereby fusing the overlapping portion of the base fabric.

[0086] For example, the first MD direction end region 1 and the second MD direction end region 2 of a base fabric are connected by... Figure 4 In the case of ultrasonic welding, the joined base fabric is in an endless shape including the dotted line portion.

[0087] The papermaking felt of the present invention is characterized in that it includes a portion fused to a base fabric, wherein the average thickness of the fused portion is 50% or more and 95% or less, preferably 60% or more and 80% or less, of the average thickness before fusion, that is, satisfying the above formula (1), preferably satisfying the above formula (2). This can be achieved by appropriately setting the fusion conditions (ultrasonic energy, distance between welding head and anvil (spacing), welding head pressure, base fabric conveying speed, and length of overlapping portion of base fabric (overlapping width of base fabric)).

[0088] In addition, such as Figure 5 As shown in (A) (before welding) and (B) (after welding), the welded portion 6 preferably includes at least the entire overlapping portion of the base fabric, and is welded linearly in such a way that the weld width and weld thickness are approximately equal, thereby maintaining the strength of the welded portion and ensuring good surface smoothness (no weld marks or base fabric marks).

[0089] There are no particular limitations on the method used for welding the overlapping portion of the base fabric; examples include ultrasonic welding, high-frequency welding, and thermal welding. Furthermore, in the case of ultrasonic welding, if pressure is applied to the overlapping portion of the base fabric with the welding head, the density of the overlapping portion is high, so the ultrasonic energy is concentrated and transmitted to that overlapping portion. Therefore, even if the width of the welding head is greater than the overlapping width of the base fabric, the welding will not be accelerated by the edge of the welding head extending beyond the overlapping portion.

[0090] Furthermore, the present invention also relates to a method for manufacturing paper felt, comprising: (a) a step of forming a base fabric having at least one of the MD direction end regions and CD direction end regions overlapping each other, which is formed by a CD wire of felt traveling direction (MD direction) and felt cross direction (CD direction) and having an MD direction end region formed by a first MD direction end region and a second MD direction end region and a CD direction end region formed by the first CD direction end region and the second CD direction end region;

[0091] (b) Without removing part or all of the overlapping MD or CD wires in step (a), the overlapping portions are completely welded together, and the overlapping end regions are joined together, such that when the average thickness of the welded portion in each base fabric is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y satisfies the following equation (1):

[0092] 0.5≤x / y≤0.95 (1);

[0093] (c) Repeat steps (a) and (b) as needed to form a ring shape that closes at least one piece of base fabric.

[0094] The manufacturing method of the present invention preferably includes: in step (b), joining the overlapping end regions together such that when the average thickness of the welded portion is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y satisfies the following equation (2):

[0095] 0.6≤x / y≤0.8 (2).

[0096] In addition, the present invention also relates to a papermaking felt, wherein the felt is manufactured by the aforementioned manufacturing method.

[0097] Example

[0098] The following describes in detail the base fabric for papermaking felt of the present invention using examples, but these examples do not limit the present invention in any way.

[0099] The base fabrics of Examples 1-5 and Comparative Examples 1 and 2 were fabricated using the MD and CD wires shown below. The MD-direction ends of the fabricated base fabrics were welded together under the welding conditions described in Table 1. The welding was performed using an ultrasonic welding machine with a welding head width of 5 mm (cubic parallelepiped, without a rotating mechanism) and an anvil of 30 mm (cylindrical, with a rotating mechanism).

[0100] The weld width, weld thickness x, base thickness y, ratio of weld thickness to base thickness x / y, trace index, and strength of the welded portion after welding are shown in Table 2.

[0101] ·MD wire: 550dtex polyamide 6 monofilament

[0102] 100 pieces / 5cm

[0103] • CD wire: 500dtex polyamide 6 monofilament

[0104] 40 pieces / 5cm

[0105] • Weave: Satin weave (31 flecks) single-layer weave

[0106] • Mass per unit area: 200g / m² 2

[0107] • Thickness before welding (base thickness): 0.63mm

[0108] • Base fabric dimensions: Length (MD direction) 3m × Width (CD direction) 1m

[0109] [Table 1]

[0110]

[0111] [Table 2]

[0112]

[0113] In addition, the base fabrics of Examples 6-10 and Comparative Examples 3 and 4 were fabricated using the MD and CD wires shown below. The MD-direction ends of the fabricated base fabrics were welded together under the welding conditions described in Table 3. The welding was performed using an ultrasonic welding machine with a welding head width of 5 mm (cubic parallelepiped, without a rotating mechanism) and an anvil of 30 mm (cylindrical, with a rotating mechanism).

[0114] The weld width, weld thickness x, base thickness y, ratio of weld thickness to base thickness x / y, trace index, and strength of the welded portion after welding are shown in Table 4.

[0115] •MD Wire: A twisted wire made by further twisting two monofilaments of polyamide 6 with a diameter of 330dB.

[0116] 35 pieces / 5cm

[0117] • CD wire: A monofilament twisted wire made by twisting three 330dN polyamide 6 monofilaments together.

[0118] 40 pieces / 5cm

[0119] • Structure: Plain weave (11 yarn repeats), single-layer structure

[0120] • Mass per unit area: 250g / m² 2

[0121] • Base thickness: 0.82mm

[0122] • Base fabric dimensions: Length (MD direction) 3m × Width (CD direction) 1m

[0123] [Table 3]

[0124]

[0125] [Table 4]

[0126]

[0127] The trace index in Tables 2 and 4 refers to the index used to evaluate surface smoothness. The evaluation method is as follows: a needle-punched fiber layer (fineness 22 dtex, 100 g / m²) is placed on a base fabric with welded sections. 2 Then, carbon paper and PPC paper are placed on top, and the resulting product is passed between two rollers (roller pressure: 50 kgf / cm). The weld line (base fabric mark) is transferred to the PPC paper until the weld line (base fabric mark) can no longer be identified. Then, 100 g / m² is added. 2 The number of fiber layers per unit area is used for evaluation. In this evaluation, for a product under a certain pressure, the smaller the unit area mass of the fiber layers disposed on the base fabric, the better the traceability (surface smoothness).

[0128] In addition, in Examples 1-5 and Comparative Examples 1 and 2, the unit area mass of the fiber layer of Comparative Example 1 with unconfirmed weld marks (base fabric marks) was 1800 g / m². 2 Set to 100%, in Examples 6-10 and Comparative Examples 3 and 4, the unit area mass of the fiber layer of Comparative Example 3 with unconfirmed weld marks (base fabric marks) was 2600 g / m². 2 The percentage was set to 100%, and relative evaluations were conducted accordingly.

[0129] The strength in Tables 2 and 4 refers to the breaking strength of the base fabric when it is stretched at 200 mm / min along the length direction by sampling a sample taken at the center of the length direction with a length of 30 cm and a width of 5 cm, with the welded part parallel to the width direction.

[0130] As shown in the table, by making the thickness of the welded portion 50% to 95% of the base thickness, the trace index is improved, and the surface smoothness of the paper felt is enhanced. Furthermore, since the MD or CD wires in the end region are not removed from the welded portion, the density of the welded portion is increased, thus the strength of the embodiment is higher than that of the comparative example.

[0131] Explanation of symbols

[0132] B、B'、B” base cloth

[0133] 1, 1', 1” First MD direction end region

[0134] 2, 2', 2” Second MD direction end region

[0135] 3, 3' First CD direction end region

[0136] 4, 4' Second CD direction end region

[0137] 5. Central area (base)

[0138] 6. Welded section

[0139] 10 Welding heads

[0140] 11 Anvil

Claims

1. A papermaking felt comprising at least one base fabric formed from CD wires in a felt transition direction (MD direction) and a felt cross-sectional direction (CD direction) and having MD-direction end regions formed by a first MD-direction end region and a second MD-direction end region, and CD-direction end regions formed by the first CD-direction end region and the second CD-direction end region, wherein at least one of the MD-direction end regions and CD-direction end regions overlaps with each other, without removing part or all of the MD wires or CD wires in the overlapping portion, wherein the overlapping portion is fused together, wherein... When the average thickness of the welded portion in each base fabric is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y of at least one base fabric satisfies the following equation (1): 0.5≤x / y≤0.95 (1); The first MD direction end region, the second MD direction end region, the first CD direction end region, and the second CD direction end region are each composed of MD wires and CD wires; and, The fibers that make up MD and CD wires are made of thermoplastic resin. The fibers that make up MD and CD wires are monofilaments, multifilaments, short fiber yarns, processed yarns, or twisted yarns made by twisting these yarns together. The base fabric can be a single-layer or multi-layer fabric.

2. The papermaking felt according to claim 1, wherein, When the average thickness of the welded portion is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y of at least one base fabric satisfies the following equation (2): 0.6≤x / y≤0.8 (2).

3. The papermaking felt according to claim 1 or 2, wherein, The first MD direction end region and the second MD direction end region of a base fabric overlap each other, without removing part or all of the overlapping CD wire, and the overlapping part is fused together.

4. The papermaking felt according to claim 1 or 2, wherein, The first MD direction end regions and the second MD direction end regions of two or more base fabrics overlap each other, without removing part or all of the overlapping CD wire, and the overlapping part is fused together.

5. The papermaking felt according to claim 1 or 2, wherein, The first MD direction end regions and the second MD direction end regions of two or more base fabrics overlap with each other, and the first CD direction end regions and the second CD direction end regions do not remove part or all of the overlapping CD wires or MD wires, and the overlapping parts are fused together.

6. The papermaking felt according to claim 1 or 2, wherein, The first CD-direction end region and the second CD-direction end region of a base fabric overlap each other, without removing part or all of the overlapping MD wire, and the overlapping part is fused together.

7. The papermaking felt according to claim 1 or 2, wherein, The first CD direction end regions and the second CD direction end regions of two or more base fabrics overlap each other, without removing part or all of the overlapping MD wire, and the overlapping part is fused together.

8. The papermaking felt according to claim 1 or 2, wherein, The overlap width (length in the MD direction) when the end regions in the MD direction overlap with each other, or the overlap width (length in the CD direction) when the end regions in the CD direction overlap with each other, is 1.0 mm to 3.0 mm.

9. The papermaking felt according to claim 1 or 2, wherein, The weld width (length in the MD direction) of the overlapping portion when the end regions in the MD direction overlap each other, or the weld width (length in the CD direction) of the overlapping portion when the end regions in the CD direction overlap each other, is 1.0mm to 5.0mm.

10. The papermaking felt according to claim 1 or 2, wherein, At least one of the MD or CD wires of the base fabric is a thermoplastic resin with a heat resistance temperature of 60℃~200℃ and a melting point of 80℃~300℃.

11. The papermaking felt according to claim 1 or 2, wherein, At least one base fabric has a unit area mass of 100 g / m². 2 ~500g / m 2 .

12. A method for manufacturing papermaking felt, wherein, include: (a) A process in which a base fabric formed by a CD wire in the felt moving direction (MD direction) and the felt transverse direction (CD direction) and having an MD direction end region formed by a first MD direction end region and a second MD direction end region and a CD direction end region formed by a first CD direction end region and a second CD direction end region overlaps with at least one of the MD direction end regions and the CD direction end regions. (b) Without removing part or all of the overlapping MD or CD wires in step (a), the overlapping portions are completely welded together, and the overlapping end regions are joined together, such that when the average thickness of the welded portion in each base fabric is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y satisfies the following equation (1): 0.5≤x / y≤0.95 (1); The first MD direction end region, the second MD direction end region, the first CD direction end region, and the second CD direction end region are each composed of MD wires and CD wires; (c) Repeat steps (a) and (b) as needed to form a ring shape that closes at least one piece of base fabric; and, The fibers that make up MD and CD wires are made of thermoplastic resin. The fibers that make up MD and CD wires are monofilaments, multifilaments, short fiber yarns, processed yarns, or twisted yarns made by twisting these yarns together. The base fabric can be a single-layer or multi-layer fabric.

13. The manufacturing method according to claim 12, wherein, include: In step (b), the overlapping end regions are joined together such that when the average thickness of the welded portion is set as x (mm) and the average thickness before welding is set as y (mm), the relationship between x and y satisfies the following equation (2): 0.6≤x / y≤0.8 (2).

14. A type of felt for papermaking, wherein, The felt is manufactured by the method described in claim 12 or 13.

Images