Crimping device, crimped fiber manufacturing device, method for manufacturing crimped fiber, and pair of side members

Abstract

To provide a crimping device capable of suppressing agglutination of fibers due to friction.SOLUTION: The present invention provides a crimping device, which includes a pair of rollers to nip fibers and a pair of lateral members disposed on both lateral surfaces of the pair of rollers so as to face each other. The pair of lateral members individually have a concavity having an opening on a surface facing the roller and are formed using resin material, and the concavity has a specific size. The present invention also provides a crimped fiber manufacturing device including the crimping device. The present invention also provides a crimped fiber manufacturing method using the crimping device or the crimped fiber manufacturing device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a crimping device, a crimped fiber manufacturing device, a method for manufacturing crimped fibers, and a pair of side members. to.

Background Art

[0002] Crimped fibers can generally be manufactured by collecting a large number of undrawn yarns obtained by spinning into a tow, subjecting this tow to stretching heat treatment, and imparting mechanical crimping as necessary. In a crimping device for imparting mechanical crimping, the fibers may adhere or break due to friction.

[0003] Means for reducing the friction of fibers have been variously proposed so far, and a so-called slide plate is known as one of such means. The slide plate is a pair of flat contact plates arranged at both ends of the pushing roller for the purpose of protecting the end portions of both ends of the tow passing through the nip points at both ends of the pushing roller from friction. The slide plate is generally formed of a metal material such as a copper alloy or an aluminum alloy having a lower hardness than the pushing roller, or a plastic material.

[0004] The metal slide plate can wear over time. The cause of the wear is the contact with both ends of the pushing roller and the friction with the tow passing through the nip points at both ends of the pushing roller. Due to the wear of the slide plate, contamination of the product with metal powder and line contamination by metal ions can occur. Therefore, the metal slide plate is not particularly suitable for the production of fibers for industrial materials such as battery separators.

[0005] The plastic slide plate can wear in a relatively short time. The cause of the wear is the friction with the tow passing through the nip portions at both ends of the pushing roller. The ends of the tow may adhere or break due to friction with the slide plate, and the dispersibility of the fibers may be significantly impaired.

[0006] Also, as another means for reducing the friction of the fibers, Patent Document 1 below discloses a technique in which the inner wall portion of a pressure box is composed of a metal belt in a pressure box type crimping device.

Prior Art Document

Patent Document

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The main object of the present invention is to provide a crimping device capable of suppressing the adhesion of fibers due to friction.

Means for Solving the Problems

[0009] That is, the present invention includes a pair of rollers for nipping the fibers and a pair of side members disposed opposite to both side surfaces of the pair of rollers, each of the pair of side members includes a recess having an opening on the surface facing the roller, and is formed using a resin material, each of the recesses is located at a position corresponding to each nip point of the pair of rollers, in the opening, when a first virtual line parallel to the moving direction of the fiber is drawn through the point corresponding to the nip point, the intersection of the first virtual line and the upstream end of the opening in the moving direction is defined as the first intersection point, and the intersection of the first virtual line and the downstream end of the opening in the moving direction is defined as the second intersection point, the second length between the point corresponding to the nip point and the second intersection point is longer than the first length between the nip point and the point corresponding to the first intersection point, the present invention provides a crimping device in which the second length is 4.0% or more of the diameter of the roller. The second length may be 8.0% or less of the diameter of the roller. The first length may be 0.5% or more and 2.5% or less of the diameter of the roller. In the opening, a second virtual line perpendicular to the moving direction of the fiber is drawn through the point corresponding to the nip point. Assuming the moving direction is the left - right direction, the intersection of the second virtual line and the upper - side end of the opening is defined as the third intersection point, and the intersection of the second virtual line and the lower - side end of the opening is defined as the fourth intersection point. When this is the case, the first width between the point corresponding to the nip point and the third intersection point and / or the second width between the point corresponding to the nip point and the fourth intersection point may be 0.15% or more and 1.25% or less of the diameter of the roller. The depth of the recess may be 0.1% or more and 0.4% or less of the diameter of the roller. The resin material may have a Rockwell hardness of 112 or more as measured by the R scale. The resin material may have a water absorption rate of 0.25 mass% or less. The resin material may contain polyetheretherketone or polyacetal. The present invention also provides a crimped fiber manufacturing apparatus including the crimping device. The present invention also provides a method for manufacturing crimped fibers using the crimping device or the crimped fiber manufacturing apparatus. The method for manufacturing crimped fibers may include supplying a sizing agent for papermaking to each of the nip points on both side surfaces of the pair of rollers. The supply rate of the sizing agent for papermaking may be 70 mL / min or more and 130 mL / min or less. The present invention A pair of side members for a crimping device, The crimping device includes a pair of rollers for nipping fibers, The pair of side members are arranged to face both side surfaces of the pair of rollers and are used, Each of the pair of side members has a recess with an opening on the surface facing the roller, and is formed using a resin material. Each of the recesses is arranged at a position corresponding to each nip point of the pair of rollers. At the opening, a first virtual line parallel to the moving direction of the fiber is drawn through the point corresponding to the nip point. When the intersection of the first virtual line and the upstream end of the opening in the moving direction is defined as the first intersection point, and the intersection of the first virtual line and the downstream end of the opening in the moving direction is defined as the second intersection point, the second length between the point corresponding to the nip point and the second intersection point is longer than the first length between the point corresponding to the nip point and the first intersection point. A pair of side members are also provided, wherein the second length is 4.0% or more of the diameter of the roller.

Advantages of the Invention

[0010] The present invention provides a crimping device capable of suppressing adhesion of fibers due to friction. Note that the effects of the present invention are not limited to the effects described herein, and may be any of the effects described in this specification.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0012] Hereinafter, preferred embodiments for carrying out the present invention will be described. The embodiments described below show typical embodiments of the present invention, and the scope of the present invention is not limited only to these embodiments.

[0013] 1. Crimping device

[0014] Referring to FIG. 1, the crimping device 1 according to the present embodiment will be described. FIG. 1 is a diagram schematically showing the crimping device 1. In FIG. 1, (A) is a schematic side view, (B) is a schematic front view, and (C) is a schematic upper perspective view.

[0015] The crimping device 1 is a device used to impart mechanical crimps to fibers. The crimping device 1 includes a pair of rollers 10, 10 that nip the fibers, and a pair of side members 20, 20 disposed opposite to both side surfaces of the pair of rollers 10, 10.

[0016] 1-1. A pair of rollers

[0017] The pair of rollers 10, 10 consists of two rollers 10. The two rollers 10 have the same shape and the same diameter. The diameter of the rollers may be, for example, 200 mm, but is not limited thereto. The pair of rollers 10, 10 are arranged vertically. The pair of rollers 10, 10 rotate and feed the tow T (fiber) in a certain direction while nipping it. The arrow MD shown in FIG. 1 indicates the moving direction of the tow T. The tow T is pressed at the nip point (the portion where the pair of rollers 10, 10 nip the tow T). For example, when the tow T passes through the nip point and the pressing is released, fine crimps can be imparted to the tow T. The tow T that has passed through the nip point is, for example, pushed into a stuffing box (not shown), and crimps can be imparted.

[0018] 1-2. A pair of side members

[0019] The pair of side members 20, 20 consists of two side members 20. The outer shapes of the two side members 20 are preferably the same. The pair of side members 20, 20 are arranged to face both side surfaces of the pair of rollers 10, 10. Specifically, one side member 20 (hereinafter also referred to as "the first side member 20a") faces at least a part of one side surface of each roller 10. That is, the first side member 20a faces at least a part of one side surface of the pair of rollers 10, 10 (hereinafter also referred to as "the first side surface of the pair of rollers 10, 10"). The other side member 20 (hereinafter also referred to as "the second side member 20b") faces at least a part of the other side surface of each roller 10. That is, the second side member 20b faces at least a part of the other side surface of the pair of rollers 10, 10 (hereinafter also referred to as "the second side surface of the pair of rollers 10, 10").

[0020] Each of the pair of side members 20, 20 (the first side member 20a and the second side member 20b) is provided with a recess having an opening on the surface facing the roller 10. The recesses of the first side member 20a and the second side member 20b are preferably the same shape. Each of these recesses is at a position corresponding to the nip point of the pair of rollers 10, 10. That is, the recess of the first side member 20a is at a position corresponding to the nip point of the first side surface of the pair of rollers 10, 10. The recess of the second side member 20b is at a position corresponding to the nip point of the second side surface of the pair of rollers 10, 10.

[0021] Examples of the shape of the opening include circular shape, elliptical shape, semi-circular shape, triangular shape, rounded triangular shape, square shape, rounded square shape, rectangular shape, rounded rectangular shape, polygonal shape with five or more sides, and rounded polygonal shape with five or more sides. The shape of the opening is preferably an elliptical shape or a rounded rectangular shape.

[0022] The recess has a bottom surface in addition to the opening. Examples of the shape of the bottom surface include flat bottom shape, round bottom shape, U-bottom shape, and V-bottom shape. The shape of the bottom surface is preferably a round bottom shape or a U-bottom shape.

[0023] FIG. 2 is a diagram schematically showing an example of the shape of the recess 22 having the opening 21. The shape of the recess 22 is preferably a shape composed of an elliptical opening 21 and a round bottom surface portion, a shape composed of an elliptical opening 21 and a U-shaped bottom surface portion, a shape composed of a rounded rectangular opening 21 and a round bottom surface portion, or a shape composed of a rounded rectangular opening 21 and a U-shaped bottom surface portion.

[0024] Referring to FIG. 3, the size of the opening 21 will be described. FIG. 3 is a schematic diagram showing the opening 21. The arrow MD shown in FIG. 3 indicates the moving direction of the fiber (ear). In FIG. 3, the left side is the upstream side in the moving direction of the fiber (ear), and the right side is the downstream side.

[0025] The units of length, width, and depth described below are not particularly limited, but may be, for example, "mm".

[0026] The opening 21 is located at a position corresponding to the nip point NP of the pair of rollers 10, 10. In the opening 21, a first virtual line VL1 parallel to the moving direction of the fiber is drawn through the point corresponding to the nip point NP. The intersection of the first virtual line VL1 and the upstream end of the moving direction of the opening 21 is defined as the first intersection point P1. The intersection of the first virtual line VL1 and the downstream end of the moving direction of the opening 21 is defined as the second intersection point P2. At this time, the second length L2 between the point corresponding to the nip point NP and the second intersection point is longer than the first length L1 between the point corresponding to the nip point NP and the first intersection point P1, and the second length L2 is 4.0% or more of the diameter of the roller 10. If the second length L2 is shorter than the first length L1, or if the second length L2 is less than 4.0% of the diameter of the roller 10, the adhesion at both ends of the ear may not be sufficiently suppressed.

[0027] The lower limit of the second length L2 is preferably 4.5% or more, more preferably 5.0% or more, still more preferably 5.5% or more of the diameter of the roller 10. The upper limit of the second length L2 is preferably 8.0% or less, more preferably 7.5% or less, still more preferably 7.0% or less, particularly preferably 6.5% or less of the diameter of the roller 10. The preferable numerical range of the second length L2 may be a combination selected from the lower limit and the upper limit described above. The second length L2 is preferably 4.0% or more and 8.0% or less, more preferably 4.5% or more and 7.5% or less, still more preferably 5.0% or more and 7.0% or less, particularly preferably 5.5% or more and 6.5% or less or 5.5% or more and 6.0% or less of the diameter of the roller 10. In order to more effectively suppress the sticking or breaking of both ends of the ear, the numerical range of the second length L2 as described above is preferable. Also, it is preferable that the second length L2 is not excessively long. This is to enable the ear passing through the nip point NP to be smoothly sent to the next process.

[0028] The lower limit of the first length L1 is preferably 0.5% or more, more preferably 0.75% or more, still more preferably 1.0% or more, particularly preferably 1.25% or more or 1.5% or more of the diameter of the roller 10. The upper limit of the first length L1 is preferably 2.5% or less, more preferably 2.25% or less, still more preferably 2.0% or less of the diameter of the roller 10. The preferable numerical range of the first length L1 may be a combination selected from the lower limit and the upper limit described above. The first length L1 is preferably 0.5% or more and 2.5% or less, more preferably 0.75% or more and 2.5% or less, still more preferably 1.0% or more and 2.25% or less, particularly preferably 1.25% or more and 2.25% or less or 1.5% or more and 2.0% or less of the diameter of the roller 10. In order to more effectively suppress the sticking or breaking of both ends of the ear, the numerical range of the first length L1 as described above is preferable.

[0029] Next, with reference to FIG. 3, the opening 21 will be described. In the opening 21, a second virtual line VL2 perpendicular to the fiber movement direction is drawn through the point corresponding to the nip point NP. The movement direction is the left - right direction. The intersection of the second virtual line VL2 and the upper - side end of the opening 21 is defined as the third intersection point P3. The intersection of the second virtual line VL2 and the lower - side end of the opening 21 is defined as the fourth intersection point P4. At this time, the first width W1 between the point corresponding to the nip point NP and the third intersection point P3 and / or the second width W2 between the point corresponding to the nip point NP and the fourth intersection point P4 are preferably a predetermined length with respect to the diameter of the roller 10.

[0030] The lower limit of the first width W1 and / or the second width W2 is preferably 0.15% or more, more preferably 0.25% or more, even more preferably 0.5% or more of the diameter of the roller 10. The upper limit of the first width W1 and / or the second width W2 is preferably 1.25% or less, more preferably 1.0% or less, even more preferably 0.75% or less of the diameter of the roller 10. The preferable numerical range of the first width W1 and / or the second width W2 may be a combination selected from the lower limit and the upper limit described above. The first width W1 and / or the second width W2 is preferably 0.15% or more and 1.25% or less, more preferably 0.25% or more and 1.0% or less, even more preferably 0.25% or more and 0.75% or less, particularly preferably 0.5% or more and 0.75% or less of the diameter of the roller 10. In order to more effectively suppress the adhesion or breakage at both ends of the tow, it is preferable that the first width W1 and / or the second width W2 is in the above - mentioned numerical range, and it is more preferable that both the first width W1 and the second width W2 are in the above - mentioned numerical range. The first width W1 and the second width W2 are preferably the same numerical value.

[0031] The depth D of the recess 22 is preferably a predetermined length with respect to the diameter of the roller 10. The depth D of the recess 22 is the distance from the opening surface surrounded by the opening 21 to the deepest part of the bottom surface. An example of the depth D is shown in FIG. 2. The lower limit of the depth D is preferably 0.1% or more, more preferably 0.15% or more, and even more preferably 0.2% or more of the diameter of the roller 10. The upper limit of the depth D is preferably 0.4% or less, more preferably 0.35% or less, and even more preferably 0.3% or less of the diameter of the roller 10. The preferable numerical range of the depth D may be a combination selected from the lower limit and the upper limit described above. The depth D is preferably 0.1% or more and 0.4% or less, more preferably 0.1% or more and 0.35% or less, even more preferably 0.1% or more and 0.3% or less, and particularly preferably 0.15% or more and 0.3% or less or 0.2% or more and 0.3% or less of the diameter of the roller 10. Such a numerical range of the depth D is preferable in order to more effectively suppress sticking or breakage at both ends of the ear.

[0032] The reason why sticking at both ends of the ear is suppressed by the recess 22 having the opening 21 of a specific size is considered to be that the recess 22 can effectively accommodate the ear. This reason will be specifically described with reference to FIG. 4.

[0033] First, FIG. 4 will be described. FIG. 4 is a diagram schematically showing the positional relationship between both ends of the ear T and the recess 22 having the opening 21. The diagrams of (A) to (C) in FIG. 4 correspond to the diagrams of (A) to (C) in FIG. 1. (A) in FIG. 4, specifically (A1) to (A3), is an enlarged schematic view of the vicinity of the nip point in (A) of FIG. 1. In (A) of FIG. 4, the arrow MD indicates the moving direction of the ear T, and the virtual line (two-dot chain line) is a line passing through the nip point and perpendicular to the moving direction MD of the ear. (B) in FIG. 4, specifically (B1) to (B3), is an enlarged schematic view of the vicinity of one side member in (B) of FIG. 1 with the recess 22 visualized. (C) in FIG. 4, specifically (C1) to (C3), is an enlarged schematic view of the vicinity of one side member in (C) of FIG. 1 with the recess 22 visualized. In (C) of FIG. 4, the arrow MD indicates the moving direction of the ear T. (A1), (B1), and (C1) in FIG. 4 are examples where sticking and breaking at both ends of the ear are suppressed, and Example 1 described later is given as an example. (A2), (B2), and (C2) in FIG. 4 are examples where sticking and breaking at both ends of the ear are not suppressed, and Comparative Example 11 described later is given as an example. (A3), (B3), and (C3) in FIG. 4 are other examples where sticking and breaking at both ends of the ear are not suppressed, and Comparative Example 15 described later is given as an example.

[0034] Next, the reason why sticking and breaking at both ends of the ear are suppressed will be explained. In Example 1, the second length L2 of the opening 21 is longer than the first length L1, and the second length L2 is 4.0% or more of the diameter of the roller 10. Therefore, the opening 21 is wider on the downstream side than on the upstream side of the nip point. As a result, as shown in (A1), (B1), and (C1) of FIG. 4, it is considered that the ear T1 spreading from the pair of rollers 10, 10 enters from the opening 21 into the recess 22 and is effectively accommodated inside the recess 22. It is considered that the recess 22 effectively releases the ear T1 spreading from the pair of rollers 10, 10. In this way, it is considered that the friction at both ends of the ear is reduced, and as a result, sticking and breaking at both ends of the ear are suppressed.

[0035] In Comparative Example 11, the second length L2 of the opening 21 is shorter than the first length L1. That is, the opening 21 is wider on the upstream side than on the downstream side of the nip point. Therefore, as shown in (A2) and (C2) of FIG. 4, the tow T2 spreading out from the pair of rollers 10, 10 is considered to be pushed into the downstream side of the recess 22. As a result, the spreading tow T2 is considered to adhere and break.

[0036] In Comparative Example 15, the opening 21 is not at the position corresponding to the nip point. Therefore, as shown in (A3) and (C3) of FIG. 4, the tow T3 spreading out from the pair of rollers 10, 10 is considered to be crushed before being accommodated in the recess 22. As a result, the spreading tow T3 is considered to adhere and break.

[0037] In the present embodiment, the pair of side members are formed using a resin material. The pair of side members are preferably formed only from the resin material. That is, the pair of side members preferably consist of a resin material.

[0038] The resin material preferably has a Rockwell hardness measured on the R scale of 112 or more, more preferably 115 or more, even more preferably 120 or more, and particularly preferably 125 or more. By having such a high hardness, wear of the pair of side members can be effectively suppressed.

[0039] The Rockwell hardness of the resin material can be the nominal value of the manufacturer that produced the resin material. For example, when such a nominal value does not exist (for example, when it is not a commercially available resin material) or when the nominal value is unknown, the Rockwell hardness can be a value measured in accordance with ASTM D785 (scale: R).

[0040] The water absorption rate of the resin material is preferably 0.25% by mass or less, more preferably 0.20% or less, and even more preferably 0.15% or less. Due to such a low water absorption rate, even when the pair of side members are used for a long period of time, it is difficult for them to absorb moisture and as a result, they are difficult to expand. Therefore, the pair of side members formed using a resin material having such a water absorption rate are suitable for long-term use.

[0041] The water absorption rate of the resin material may be the nominal value of the manufacturer that produced the resin material. For example, when such a nominal value does not exist (for example, when it is not a commercially available resin material) or when the nominal value is unknown, the water absorption rate may be the value measured in accordance with ASTM D570.

[0042] The resin material may be one kind or a combination of two or more kinds of known resin materials. The resin material preferably contains polyetheretherketone (PEEK) or polyacetal (POM), and more preferably contains PEEK.

[0043] As described in detail above, the pair of side members can suppress the adhesion of fibers in the coiling device. Therefore, the present invention also provides a pair of side members for a coiling device. The pair of side members according to an embodiment of the present invention are as described in 1-2. above, and the description also applies to this embodiment.

[0044] An example of a pair of side members for a crimping device according to this embodiment is as follows. The crimping device includes a pair of rollers that nip a fiber. The pair of side members are disposed opposite to both side surfaces of the pair of rollers and used. Each of the pair of side members includes a recess having an opening on a surface facing the roller and is formed using a resin material. Each of the recesses is disposed at a position corresponding to each nip point of the pair of rollers. A first virtual line parallel to the moving direction of the fiber is drawn through a point corresponding to the nip point at the opening, and an intersection of the first virtual line and an upstream end of the moving direction of the opening is defined as a first intersection point, and an intersection of the first virtual line and a downstream end of the moving direction of the opening is defined as a second intersection point. At this time, a second length between the point corresponding to the nip point and the second intersection point is longer than a first length between the point corresponding to the nip point and the first intersection point, and the second length is 4.0% or more of the diameter of the roller.

[0045] 1-3. Other members

[0046] The crimping device according to this embodiment may include other members. The other members may be, for example, known members used in a fiber crimping device. The crimping device according to this embodiment may include, for example, a stuffing box. The stuffing box is disposed on the downstream side in the moving direction of the fiber (tow) of the pair of rollers. The tow that has passed through the nip point of the pair of rollers is pushed into the stuffing box. The fiber buckles inside the stuffing box and crimps are imparted.

[0047] 1-4. Crimped fiber

[0048] By the crimping device according to this embodiment, the fibers are crimped to produce crimped fibers. The material used for the fibers may be, for example, a resin material, preferably at least one selected from polyolefin, polyester, polyamide, polyacetal, polycarbonate, and polyetherimide, and more preferably polyolefin. The polyolefin is preferably at least one selected from high-density polyethylene, polypropylene, and ethylene copolymer random copolymer. In particular, fibers containing such polyolefin on the surface are preferred. The unit fineness of the crimped fibers is preferably 0.2 dtex or more and 20 dtex or less, and more preferably 0.8 dtex or more and 6.6 dtex or less.

[0049] 2. Crimped Fiber Manufacturing Apparatus

[0050] The present invention also provides a crimped fiber manufacturing apparatus including the crimping device described in 1. above. The crimping device included in the crimped fiber manufacturing apparatus according to an embodiment of the present invention is as described in 1. above, and this description also applies to this embodiment.

[0051] The crimped fiber manufacturing apparatus according to this embodiment may include devices other than the crimping device. Devices other than the crimping device may be appropriately selected by those skilled in the art from known devices in the art according to the type and use of the crimped fibers, etc. For example, when manufacturing crimped staple fibers using a resin material, the crimped fiber manufacturing apparatus may include a device for melt-spinning the resin material, a device for stretching the spun fibers (tows), a device for attaching an oil agent to the fibers (tows), a device for drying the crimped fibers obtained by the crimping device, and a device for cutting the dried crimped fibers, etc.

[0052] 3. Manufacturing Method of Crimped Fibers

[0053] The present invention also provides a method for manufacturing crimped fibers using the crimping device described in 1. above or the crimped fiber manufacturing device described in 2. above. The crimping device or the crimped fiber manufacturing device used in the manufacturing method according to an embodiment of the present invention is as described in 1. or 2. above, and the description thereof also applies to this embodiment.

[0054] The manufacturing method according to this embodiment preferably includes supplying a sizing oil agent to each nip point on both side surfaces of a pair of rollers. Supplying the sizing oil agent increases the lubricity at both ends of the tow, contributes to preventing breakage and sticking at both ends of the tow, and can also contribute to suppressing wear of the side members. In this case, the crimping device or the crimped fiber manufacturing device may include, for example, an oil agent supply unit that supplies the sizing oil agent to each of the nip points. The supply of the sizing oil agent is preferably carried out continuously while imparting crimp to the fibers.

[0055] The sizing oil agent may be an oil agent used when manufacturing a non-woven fabric by a papermaking method using fibers as raw materials, and may be one kind or a combination of two or more kinds of such oil agents. The sizing oil agent used in this embodiment is preferably at least one selected from ester-based oil agents, fatty acid soaps, phosphate metal salts of higher alcohols having 8 to 22 carbon atoms, silicone-based oil agents, and anionic surfactants.

[0056] Depending on the type, the sizing oil agent may be diluted with water and used. In this case, the concentration of the diluted sizing oil agent is preferably 1% by mass or more and 10% by mass or less.

[0057] In the manufacturing method according to this embodiment, for example, when the fibers are stretched and a finishing oil agent is used after stretching, the sizing oil agent is preferably the same or similar to the finishing oil agent or a dilution thereof, and more preferably the same as the finishing oil agent or a dilution thereof. For example, the sizing oil agent may be an aqueous solution obtained by diluting the finishing oil agent with water.

[0058] The speed of supplying sizing oil for papermaking to each nip point on both side surfaces of a pair of rollers is preferably 70 mL / min or more and 130 mL / min or less at each nip point. At such a supply speed, the lubricity at both ends of the tow increases, which is effective in preventing breakage and sticking at both ends of the tow, and is also effective in suppressing wear of the side members. From the viewpoint of obtaining sufficient lubricity, the above lower limit value is preferable, and from the viewpoint of cost, the above upper limit value is preferable.

Example

[0059] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0060] (1) Production of crimped staple fibers

[0061] Using a crimped fiber production apparatus including a crimping device, crimped staple fibers were produced according to the following procedure. The crimping device was an apparatus including at least a pair of rollers, a pair of side members disposed opposite to both side surfaces of the pair of rollers, and a stuffing box.

[0062] <Example 1>

[0063] A first resin material (polypropylene) forming a core part and a second resin material (high-density polyethylene) forming a sheath part were melt-spun in a sheath-core form to obtain an undrawn yarn. After stretching in warm water at 85°C or higher or in steam at 100°C or higher, a sizing oil for papermaking (an anionic surfactant containing polyether) was attached. Then, crimps were imparted to the fibers using a crimping device. In the crimping device, an aqueous solution of sizing oil for papermaking (a 5 mass% aqueous solution of an anionic surfactant containing polyether) was supplied to each nip point on both side surfaces of a pair of rollers at a speed of 100 mL / min. In the crimping device, the nip pressure was 0.11 MPa and the stuffing pressure was 0.09 MPa. Then, the crimped fibers were cut to 5 mm with a rotary cutter. Thereby, crimped staple fibers having a single-fiber fineness of 1.7 dtex, a crimp number of 11 to 25 pieces / 25 mm, and a fiber length of 5.2 mm were obtained.

[0064] As shown in Fig. 1, the pair of rollers consists of two rollers of the same shape arranged vertically, and the diameter of each roller was 200 mm. Each of the pair of side members had a recess consisting of a rounded rectangular opening and a bottom surface portion with a round bottom shape. The pair of side members was made of the following resin material, and the recess had the following dimensions (length, width, and depth). Note that the definitions of these length, width, and depth are as described in 1-2 above.

[0065] [Resin material] Polyetheretherketone (PEEK) Rockwell hardness of R scale: 125 (manufacturer's nominal value) Water absorption rate: 0.14 mass% (manufacturer's nominal value)

[0066] [Dimensions of the recess] First length L1: 3.0 mm Second length L2: 12.0 mm First width W1: 1.5 mm Second width W2: 1.5 mm Depth D: 0.50 mm

[0067] <Example 2>

[0068] Except that the single fiber fineness of the crimped staple fiber was changed to 3.3 dtex and the number of crimps was changed to 6 to 24 per 25 mm, the crimped staple fiber was obtained under the same conditions as in Example 1. The fiber length of the crimped staple fiber was the same as 5.2 mm in Example 1.

[0069] <Example 3>

[0070] Except that the first length L1 was changed to 4.0 mm and the second length L2 was changed to 11.0 mm, and the sizing agent for papermaking was not supplied in the crimping device, the crimped staple fiber was obtained under the same conditions as in Example 1.

[0071] <Example 4>

[0072] Except for not supplying the sizing agent for papermaking in the crimping device, crimped short fibers were obtained under the same conditions as in Example 1.

[0073] <Example 5>

[0074] A pair of side members were changed to those made of the following resin materials, and except for not supplying the sizing agent for papermaking in the crimping device, crimped short fibers were obtained under the same conditions as in Example 1.

[0075] [Resin material] Polyacetal (POM) Rockwell hardness of R scale: 112 (manufacturer's nominal value) Water absorption rate: 0.22 - 0.25 mass% (manufacturer's nominal value)

[0076] <Example 6>

[0077] Except for changing the first width W1 to 0.5 mm and the second width W2 to 0.5 mm, crimped short fibers were obtained under the same conditions as in Example 5.

[0078] <Example 7>

[0079] Except for changing the first length L1 to 4.0 mm and the second length L2 to 16.0 mm, and supplying an aqueous solution of the sizing agent for papermaking (5 mass% aqueous solution of an anionic surfactant containing polyether) at a rate of 100 mL / min to each nip point on both sides of the pair of rollers in the crimping device, crimped short fibers were obtained under the same conditions as in Example 5.

[0080] <Example 8>

[0081] Except for changing the second length L2 to 11.0 mm, the first width W1 to 2.0 mm, and the second width W2 to 2.0 mm, crimped short fibers were obtained under the same conditions as in Example 7.

[0082] <Example 9>

[0083] Except for changing the second length L2 to 11.0 mm, the first width W1 to 0.5 mm, and the second width W2 to 0.5 mm, the crimped staple fibers were obtained under the same conditions as in Example 7.

[0084] <Example 10>

[0085] Except for changing the second length L2 to 11.0 mm and the depth D to 0.30 mm, the crimped staple fibers were obtained under the same conditions as in Example 7.

[0086] <Comparative Example 1>

[0087] Except for changing the second length L2 to 7.0 mm, the first width W1 to 1.0 mm, and the second width W2 to 1.0 mm and not supplying the papermaking oil agent in the crimping device, the crimped staple fibers were obtained under the same conditions as in Example 1.

[0088] <Comparative Example 2>

[0089] Except for changing the first width W1 to 1.5 mm and the second width W2 to 1.5 mm, the crimped staple fibers were obtained under the same conditions as in Comparative Example 1.

[0090] <Comparative Example 3>

[0091] Except for changing the depth D to 1.00 mm, the crimped staple fibers were obtained under the same conditions as in Comparative Example 2.

[0092] <Comparative Example 4>

[0093] Except for supplying an aqueous solution of the papermaking oil agent (5% by mass aqueous solution of an anionic surfactant containing polyether) at a rate of 100 mL / min to each nip point on both side surfaces of the pair of rollers in the crimping device, the crimped staple fibers were obtained under the same conditions as in Comparative Example 2.

[0094] <Comparative Example 5>

[0095] Except for changing the pair of side members to those without recesses and not supplying the papermaking oil agent in the crimping device, the crimped staple fibers were obtained under the same conditions as in Example 1.

[0096] <Comparative Example 6>

[0097] Shrinkable staple fibers were obtained under the same conditions as in Comparative Example 1, except that the pair of side members were changed to those made of POM described in Example 5 above and having no recesses.

[0098] <Comparative Example 7>

[0099] Shrinkable staple fibers were obtained under the same conditions as in Comparative Example 1, except that the pair of side members were changed to those made of the following resin material and having no recesses.

[0100] [Resin Material] Polytetrafluoroethylene (PTFE) Rockwell hardness on the R scale: 20 (manufacturer's nominal value) Water absorption rate: 0.01% by mass (manufacturer's nominal value)

[0101] <Comparative Example 8>

[0102] Shrinkable staple fibers were obtained under the same conditions as in Comparative Example 1, except that the pair of side members were changed to those made of the following resin material and having no recesses.

[0103] [Resin Material] Perfluoroalkoxy alkane (PFA) Rockwell hardness on the R scale: 50 (manufacturer's nominal value) Water absorption rate: 0.01% by mass (manufacturer's nominal value)

[0104] <Comparative Example 9>

[0105] Shrinkable staple fibers were obtained under the same conditions as in Comparative Example 1, except that the pair of side members were changed to those made of the following resin material and having no recesses.

[0106] [Resin Material] Ultra-high molecular weight polyethylene (UHPE) Rockwell hardness on the R scale: 52 (manufacturer's nominal value) Water absorption rate: less than 0.01% by mass (manufacturer's nominal value)

[0107] <Comparative Example 10>

[0108] Shrinkable short fibers were obtained under the same conditions as in Comparative Example 1, except that a pair of side members were changed to those made of the following resin material and having no recesses.

[0109] [Resin material] Polyamide (PA) Rockwell hardness on the R scale: 120 (manufacturer's nominal value) Water absorption rate: 0.8% by mass (manufacturer's nominal value)

[0110] <Comparative Example 11>

[0111] Shrinkable short fibers were obtained under the same conditions as in Comparative Example 1, except that the first length L1 was changed to 7.0 mm and the second length L2 was changed to 3.0 mm.

[0112] <Comparative Example 12>

[0113] Shrinkable short fibers were obtained under the same conditions as in Comparative Example 11, except that the first width W1 was changed to 1.5 mm and the second width W2 was changed to 1.5 mm.

[0114] <Comparative Example 13>

[0115] Shrinkable short fibers were obtained under the same conditions as in Comparative Example 12, except that the depth D was changed to 1.00 mm.

[0116] <Comparative Example 14>

[0117] Shrinkable short fibers were obtained under the same conditions as in Example 1, except that the resin material of a pair of side members was changed to POM described in Example 5 above, the first length L1 was changed to 9.0 mm, and the second length L2 was changed to 6.0 mm.

[0118] <Comparative Example 15>

[0119] Except for changing the first length L1 to -1.0 mm and the second length L2 to 16.0 mm, crimped staple fibers were obtained under the same conditions as in Comparative Example 14. That the first length L1 is "-1.0 mm" means that the first intersection point P1 shown in FIG. 3 is located 1.0 mm downstream from the nip point NP.

[0120] In Examples 3 to 10 and Comparative Examples 1 to 15, the fineness per unit, the number of crimps, and the fiber length of the obtained crimped staple fibers were all the same as in Example 1.

[0121] (2) Evaluation of crimped tow

[0122] In Examples 1 to 10 and Comparative Examples 1 to 15, 20 m of crimped tow was collected from the crimping device. The ends of the crimped tow were stretched by finger by about 50 mm each, and the number of breakage parts (dozens of broken wires) buried in the crimps was made visible, and the number of breakage parts existing at both ends of the crimped tow was counted. The total number of breakage parts existing at both ends of the crimped tow was divided by 20 to calculate the breakage frequency (unit: pieces / m) at both ends of the tow. In the following Table 1 in which the breakage frequency is described, the term "continuous adhesion" indicates that almost the entire length of the tow end was adhered, and the term "partial adhesion" indicates that the tow end was intermittently adhered.

[0123] (3) Evaluation of crimped staple fibers

[0124] The water dispersibility of the crimped staple fibers of Examples 1 to 10 and Comparative Examples 1 to 15 was evaluated based on the results of primary opening and secondary opening. It can be said that the less the adhesion of the fibers, the better the water dispersibility. In primary opening, 20 g of crimped staple fibers were stirred in 150 L of inspection water at 1100 rpm for 50 seconds. In secondary opening, the fiber bundles that were undispersed in primary opening were extracted, and the fiber bundles were vigorously stirred at 7000 rpm in 300 mL of inspection water. The evaluation was carried out according to the following evaluation criteria. Among the following evaluation criteria, A and B were judged as qualified, and C and D were judged as unqualified.

[0125] <Evaluation criteria> A(Very good water dispersibility): There are no undispersed fiber bundles after the first stage of fiber opening, and each single fiber spreads neatly in water. B(Good water dispersibility): Undispersed fiber bundles are extracted after the first stage of fiber opening, and there are one or more but less than two undispersed fiber bundles after the second stage of fiber opening. C(Poor water dispersibility): There are two or more undispersed fiber bundles after the second stage of fiber opening. D(Very poor water dispersibility): There are several or more undispersed fiber bundles after the first stage of fiber opening, and there are many entanglements between single fibers.

[0126] (4) Evaluation of a pair of side members

[0127] In Examples 1 to 10 and Comparative Examples 1 to 15, the surfaces of a pair of side members that had been used for a total of about 24 hours were observed with a microscope, and the degree of wear of the side members was evaluated according to the following evaluation criteria.

[0128] <Evaluation criteria> Small: Almost no dents are confirmed. Medium: Slight dents are confirmed. Large: Wear marks are confirmed.

[0129] The evaluation results of Examples 1 to 10 and Comparative Examples 1 to 15 are shown in Table 1 below.

[0130]

Table 1

[0131] As shown in Table 1, in Comparative Examples 5 to 10 where a pair of side members without recesses were used, the water dispersibility of the fibers was very poor. Even in those with recesses, in Comparative Examples 11 to 14 where the second length L2 was shorter than the first length L1, the water dispersibility of the fibers was very poor, and breakage was observed in the tows. Even when the second length L2 was longer than the first length L1, in Comparative Examples 1 to 4 where the second length L2 was 3.5% (7.0 mm) of the diameter of the roller, the water dispersibility of the fibers was poor, and breakage was observed in the tows. In Comparative Example 15 where the recess was not at the position corresponding to the nip point, the water dispersibility of the fibers was very poor, and breakage was observed in the tows.

[0132] On the other hand, in Examples 1 to 10 where the second length L2 is longer than the first length L1 and the second length L2 is 4.0% or more of the diameter of the roller, the water dispersibility of the fiber was good. From these results, it is considered that the opening of the recess having a specific size in the present invention contributes to suppressing the adhesion of the fiber.

Explanation of Signs

[0133] 1 Crimping device 10 Roller 20 Side member 21 Opening 22 Recess NP nip point P1 First intersection point P2 Second intersection point P3 Third intersection point P4 Fourth intersection point T Tow VL1 First virtual line VL2 Second virtual line

Claims

1. A pair of rollers for nipping a fiber, and a pair of side members arranged to face both side surfaces of the pair of rollers, each of the pair of side members having a recess with an opening on the surface facing the roller and being formed using a resin material, each of the recesses being at a position corresponding to each nip point of the pair of rollers, in the opening, when a first virtual line parallel to the moving direction of the fiber is drawn through the point corresponding to the nip point, the intersection of the first virtual line and the upstream end of the opening in the moving direction is defined as the first intersection point, and the intersection of the first virtual line and the downstream end of the opening in the moving direction is defined as the second intersection point, the second length between the point corresponding to the nip point and the second intersection point is longer than the first length between the point corresponding to the nip point and the first intersection point, the second length is 4.0% or more of the diameter of the roller, A crimping device.

2. The second length is 8.0% or less of the diameter of the roller, the crimping device according to claim 1.

3. The first length is 0.5% or more and 2.5% or less of the diameter of the roller, the crimping device according to claim 1 or 2.

4. In the opening, when a second virtual line perpendicular to the moving direction of the fiber is drawn through the point corresponding to the nip point, with the moving direction being the left - right direction, the intersection of the second virtual line and the upper end of the opening is defined as the third intersection point, and the intersection of the second virtual line and the lower end of the opening is defined as the fourth intersection point, the first width between the point corresponding to the nip point and the third intersection point and / or the second width between the point corresponding to the nip point and the fourth intersection point is 0.15% or more and 1.25% or less of the diameter of the roller, the crimping device according to any one of claims 1 to 3.

5. The depth of the recess is 0.1% or more and 0.4% or less of the diameter of the roller, the crimping device according to any one of claims 1 to 4.

6. The resin material has a Rockwell hardness measured by the R scale of 112 or more, the crimping device according to any one of claims 1 to 5.

7. The resin material has a water absorption rate of 0.25% by mass or less, the crimping device according to any one of claims 1 to 6.

8. The resin material contains polyetheretherketone or polyacetal, the crimping device according to any one of claims 1 to 7.

9. A crimped fiber manufacturing apparatus including the crimping device according to any one of claims 1 to 8.

10. A method for manufacturing crimped fibers, using the crimping device according to any one of claims 1 to 8 or the crimped fiber manufacturing apparatus according to claim 9.

11. The method for manufacturing crimped fibers according to claim 10, including supplying a papermaking oil agent to each of the nip points on both side surfaces of the pair of rollers.

12. The method for manufacturing crimped fibers according to claim 11, wherein the supply rate of the papermaking oil agent is 70 mL / min or more and 130 mL / min or less.

13. A pair of side members for a crimping device, wherein the crimping device includes a pair of rollers for nipping fibers, the pair of side members are arranged to face both side surfaces of the pair of rollers and used, each of the pair of side members is provided with a recess having an opening on a surface facing the roller and is formed using a resin material, each of the recesses is arranged at a position corresponding to each nip point of the pair of rollers, in the opening, a first virtual line parallel to the moving direction of the fiber is drawn through a point corresponding to the nip point, and when an intersection of the first virtual line and an upstream end of the opening in the moving direction is defined as a first intersection point and an intersection of the first virtual line and a downstream end of the opening in the moving direction is defined as a second intersection point, a second length between the point corresponding to the nip point and the second intersection point is longer than a first length between the point corresponding to the nip point and the first intersection point, the second length is 4.0% or more of the diameter of the roller, A pair of side members.

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