Sheet manufacturing method and processing device

Abstract

The present invention provides a sheet manufacturing method and processing device that can impart greater stretchability to a base sheet. The sheet manufacturing method includes a conveying step of conveying a base sheet (2) and a processing step of rotationally driving a pair of processing rollers (12, 14) arranged with a conveying path (3) for conveying the base sheet (2) so that irregularities (13, 15) formed along respective outer peripheral surfaces (12s, 14s) of the processing rollers (12, 14) engage each other with a gap to stretch the base sheet (2) as the base sheet (2) passes between the processing rollers (12, 14). In the conveying step, as the base sheet (2) is conveyed, the base sheet (2) comes into contact with and is conveyed along the outer peripheral surface (12s) of one processing roller (12) before passing between the processing rollers (12, 14), and a tension (T1) applied to the base sheet (2) in the conveying direction before the base sheet reaches the outer peripheral surface (12s) of one processing roller (12) is less than 10% of a breaking load of the base sheet (2) in the conveying direction before being processed.

Description

Technical Field

[0001] This invention relates to a sheet manufacturing method and processing apparatus, and more particularly to a technique for manufacturing stretchable sheets. Background Technology

[0002] Current conventional techniques can stretch sheets to give them tensile properties. For example, Figure 6 This is a schematic diagram of the sheet processing apparatus 101. (As shown...) Figure 6 As shown, the sheet processing apparatus 101 is equipped with a pair of rollers 102 and 103, each roller having a pair of meshing teeth 120 and 130 disposed on its peripheral portion; and tension applying devices 105 and 106 disposed in front of and behind the rollers 102 and 103. When the rollers 102 and 103 are driven to rotate in the directions of arrows 202 and 203, the teeth 120 and 130 of the processing rollers 102 and 103 mesh with each other with a certain gap, and a substrate sheet 110 is disposed in the gap between the meshing teeth 120 and 130, and the substrate sheet 110 is subjected to stretching treatment in its flow direction to acquire tensile properties. The tension applying devices 105 and 106 are provided before and after the processing of the rollers 102 and 103, which can effectively impart tensile properties to the substrate sheet 110.

[0003] The tension applying device 105 has a set of rolls 151 and 152 arranged upstream of the pair of rolls 102 and 103; a tension detector (not shown) is arranged on the conveying path between the rolls 151 and 152 and the rolls 102 and 103; and a controller (not shown) controls the circumferential speed of the rolls 151 and 152 according to the detection output of the tension detector.

[0004] A tension applying device 106 provides a set of rolls 161 and 162 downstream of the pair of rolls 102 and 103; a tension detector (not shown) is provided on the conveying path between the rolls 161 and 162 and the rolls 102 and 103; and a controller (not shown) controls the circumferential speed of the rolls 161 and 162 based on the detection output of the tension detector.

[0005] The pre-processing tension applied to the substrate sheet 110 by the rolls 151 and 152 of the tension applying device 105 is 10% to 90%, preferably 20% to 80%, of the breaking load of the substrate sheet 110 along its flow direction before processing. The post-processing tension applied to the substrate sheet 110 by the rolls 161 and 162 of the tension applying device 106 is 5% to 80%, preferably 10% to 70%, of the breaking load of the substrate sheet 110 along its flow direction before processing (see, for example, Patent Document 1).

[0006] Patent document 1: Japanese Patent No. 4757139. Summary of the Invention

[0007] However, when processing the sheet material according to the above method, the tensile strength applicable to the substrate sheet 110 is also limited because the range of tension applied to the substrate sheet 110 before and after processing is limited, making it difficult to impart greater tensile strength to it.

[0008] Therefore, the problem to be solved by the present invention is to provide a sheet manufacturing method and processing apparatus that can impart greater tensile strength to the substrate sheet.

[0009] To address the above problems, the present invention provides a sheet manufacturing method, the structure of which is as follows:

[0010] The sheet manufacturing method includes: (i) a conveying step of conveying a substrate sheet; and (ii) a processing step of rotary driving a pair of processing rollers, the pair of processing rollers being arranged with a conveying path for conveying the substrate sheet spaced apart, such that as the substrate sheet passes between the processing rollers, irregular portions formed along the respective outer peripheral surfaces of the processing rollers engage with each other at a certain gap to stretch the substrate sheet. In the conveying step, as the substrate sheet is conveyed, it contacts the outer peripheral surface of one of the processing rollers and is conveyed along the outer peripheral surface before passing between the processing rollers, and the tension applied to the substrate sheet in the conveying direction before the substrate sheet reaches the outer peripheral surface of one of the processing rollers is less than 10% of the breaking load of the substrate sheet in the conveying direction before being processed.

[0011] According to the above method, when the substrate sheet is conveyed along the outer peripheral surface of a processing roller, the friction between the substrate sheet and the outer peripheral surface of the processing roller can be utilized to gradually reduce the tension applied to the substrate sheet in the conveying direction as the substrate sheet moves upstream in the conveying direction from the meshing portion where the irregular parts of the processing rollers interlock. Furthermore, the tension applied to the substrate sheet in the conveying direction can be reduced before the substrate sheet reaches the outer peripheral surface of a processing roller. Moreover, by utilizing the friction between the outer peripheral surface of the substrate sheet and the processing roller, the shrinkage of the substrate sheet in the width direction perpendicular to the conveying direction can be limited. Therefore, compared to stretching treatment performed at the meshing portion under tension in the conveying direction, greater tensile strength can be imparted to the substrate sheet.

[0012] When the tension of the substrate sheet in the conveying direction is less than 10% of the breaking load of the substrate sheet in the conveying direction before processing, the shrinkage of the substrate sheet in the width direction can be more limited before the substrate sheet reaches the outer circumferential surface of a processing roller, compared with the case where the tension of the substrate sheet before processing in the conveying direction is not less than 10% of the breaking load of the substrate sheet in the conveying direction before processing, thereby giving the substrate sheet greater tensile strength.

[0013] Preferably, the sheet manufacturing method further includes a heating step of heating a processing roller, such that the temperature of the outer peripheral surface of the processing roller is not lower than 10°C and not higher than 60°C, preferably not lower than 30°C and not higher than 60°C.

[0014] In this case, even when the substrate sheet is transported at high speed, it can be ensured that the substrate sheet will not break or be damaged during processing.

[0015] Preferably, in the conveying step, the substrate sheet is conveyed along the outer circumferential surface of a processing roller within a range of not less than 180° and not more than 270°, with the rotation center line of the processing roller as the center.

[0016] In this case, the substrate sheet is conveyed a longer distance along the outer circumference of a processing roller, and when the substrate sheet is heated by a processing roller, the substrate sheet can be heated sufficiently, thereby giving the substrate sheet greater tensile strength.

[0017] Preferably, the processing rollers are supported such that the distance between the processing rollers can be changed by moving at least one processing roller. During the processing step, the amount of meshing between the irregular portions of the processing rollers remains constant or is controlled within a predetermined range.

[0018] In this configuration, the increased distance between the pair of processing rollers makes it easier to prepare the substrate sheet by threading it between the rollers before starting the stretching process. Since the engagement amount between the irregular portions of the processing rollers remains constant or is controlled within a predetermined range during the stretching process, the variation in the stretching amount of the substrate sheet can be controlled.

[0019] Furthermore, in order to solve the above problems, the present invention provides a sheet processing apparatus, the structure of which is as follows:

[0020] A sheet processing apparatus includes a pair of processing rollers arranged with a conveying path for conveying a substrate sheet spaced apart. As the processing rollers rotate, they engage with each other at a certain gap along irregular portions formed on their respective outer circumferential surfaces. In the sheet processing apparatus, when conveying the substrate sheet, the substrate sheet contacts the outer circumferential surface of one of the processing rollers and is conveyed along the outer circumferential surface before passing between the processing rollers. The sheet processing apparatus further includes: (a) a drive roller arranged along the conveying path for bringing the substrate sheet to a processing roller and rotating and conveying the substrate sheet; and (b) a tension control device that controls the rotation of the drive roller and one or both processing rollers such that the tension applied to the substrate sheet in the conveying direction before the substrate sheet reaches a processing roller is less than 10% of the breaking load of the substrate sheet in the conveying direction before processing.

[0021] According to the above structure, the friction between the outer peripheral surfaces of the substrate sheet and a processing roller can be utilized to reduce the tension applied to the substrate sheet in the conveying direction as it moves upstream from the meshing portion where the irregular parts of the processing rollers interlock. Furthermore, the tension applied to the substrate sheet in the conveying direction can be reduced before the substrate sheet reaches the outer peripheral surface of the processing roller. Additionally, by utilizing the friction between the outer peripheral surfaces of the substrate sheet and the processing roller, the shrinkage of the substrate sheet in the width direction perpendicular to the conveying direction can be limited. Therefore, compared to stretching treatment performed at the meshing portion under tension in the conveying direction, greater tensile strength can be imparted to the substrate sheet.

[0022] When the tension of the substrate sheet in the conveying direction is less than 10% of the breaking load of the substrate sheet in the conveying direction before processing (before the substrate sheet reaches the outer peripheral surface of a processing roller), the shrinkage of the substrate sheet in the width direction can be restricted to a greater extent compared with the case where the tension of the substrate sheet before processing in the conveying direction is not less than 10% of the breaking load of the substrate sheet in the conveying direction before processing, thus giving the substrate sheet greater tensile strength.

[0023] Preferably, the sheet processing apparatus is further provided with a heater for heating a processing roller, such that the temperature of the outer circumference of the processing roller is not lower than 10°C and not higher than 60°C, preferably not lower than 30°C and not higher than 60°C.

[0024] In this case, even if the substrate sheet is transported at a high speed, it can be ensured that the substrate sheet 2 will not break or be damaged during processing.

[0025] Preferably, in the sheet processing apparatus, the substrate sheet is conveyed along the outer circumferential surface of a processing roller within a range of not less than 180° and not more than 270°, with the rotation center line of the processing roller as the center.

[0026] In this case, the substrate sheet is conveyed a longer distance along the outer circumference of a processing roller, and when the substrate sheet is heated by a processing roller, the substrate sheet can be heated sufficiently, thereby giving the substrate sheet greater tensile strength.

[0027] Preferably, the sheet processing apparatus further includes: (c) a processing roller support mechanism that supports the processing rollers so that the distance between them can be varied; (d) a processing roller moving device that moves at least one processing roller; and (e) an anti-separation device for fixing or controlling the amount of engagement between irregular portions of the processing rollers within a predetermined range.

[0028] In this configuration, the increased distance between the pair of processing rollers facilitates the preparation of the substrate sheet by passing it between the rollers before processing. By employing a separation prevention device, the engagement amount between the irregular portions of the processing rollers remains constant or is controlled within a predetermined range during the stretching process, thus allowing control over variations in the stretching amount of the substrate sheet.

[0029] According to the present invention, the substrate sheet can be given greater tensile strength. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the sheet processing apparatus in Example 1.

[0031] Figure 2 This is a block diagram of the sheet processing apparatus in Example 1.

[0032] Figure 3 This is an enlarged schematic diagram of relevant parts of the sheet processing apparatus in Example 1.

[0033] Figure 4 This is a schematic diagram of relevant parts of the sheet processing apparatus in Example 2.

[0034] Figure 5 This is a schematic diagram of the locking mechanism in Example 2.

[0035] Figure 6 This is a schematic diagram illustrating the traditional sheet processing technology. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] Example 1: As Figures 1-3 As shown, the sheet processing apparatus 10 and the sheet manufacturing method of the present invention will be described.

[0038] like Figure 1 The diagram shows the external structure of the sheet processing apparatus 10 of the present invention. In the sheet processing apparatus 10, the following components are arranged along the conveying path 3 of the substrate sheet 2 from the upstream side to the downstream side of the conveying direction of the substrate sheet 2: a first drive roller 16; guide rollers 31 and 32; a pair of processing rollers 12 and 14; guide rollers 33 and 34; a second drive roller 18; guide rollers 35 and 36; a coiling roller 20 and a rolling roller 22; and a guide roller 37.

[0039] The first drive roller 16 is rotated in the direction indicated by arrow 16r to deliver the substrate sheet 2, and conveys the substrate sheet 2 in contact with the outer peripheral surface 16s of the first drive roller 16 at the same speed as the circumferential speed of the first drive roller 16. The substrate sheet 2 conveyed in the direction indicated by arrow 2x passes between a pair of processing rollers 12 and 14 via guide rollers 31 and 32.

[0040] The circumferential speed of the first drive roller 16 is higher than that of the processing rollers 12 and 14. For example, the circumferential speed of the first drive roller 16 is 1.5 times that of the processing rollers 12 and 14. During the time until the first drive roller 16 reaches the processing rollers 12 and 14, if the tension applied to the substrate sheet 2 in the conveying direction is reduced to a level that will not cause the substrate sheet 2 to stretch, the width of the substrate sheet 2 remains unchanged, for example, 350 mm.

[0041] The pair of processing rollers 12 and 14 are arranged with a conveying path 3 spaced apart. One processing roller 12 has a plurality of spur gear-shaped teeth or teeth 13 along its outer peripheral surface 12s. The teeth 13 are arranged radially and circumferentially from the rotation center line 12x of the processing roller 12 with a predetermined tooth pitch, and each tooth 13 extends parallel to the rotation center line 12x of the processing roller 12. Similarly, the other processing roller 14 has a plurality of spur gear-shaped teeth or straight teeth 15 along its outer peripheral surface 14s. The teeth 15 are arranged radially and circumferentially from the rotation center line 14x of the processing roller 14 with a predetermined tooth pitch, and each tooth 15 extends parallel to the rotation center line 14x of the processing roller 14.

[0042] The pair of processing rollers 12 and 14 are driven to rotate synchronously in the directions indicated by arrows 12r and 14r, such that teeth 13 and 15 mesh with each other with a certain gap. For example, a meshing drive gear (not shown) is fixed to the shaft end of the rotating shaft (not shown) of the processing rollers 12 and 14, and a third motor 12m (such as...) Figure 2 The rotation (as shown) is transmitted to the drive gear. The irregular portions of teeth 13 and 15 mesh with each other with a certain gap.

[0043] When the substrate sheet 2 passes through the meshing portion 12b of the teeth 13 and 15 of processing rollers 12 and 14, which mesh with each other at a certain gap, the substrate sheet 2 is subjected to stretching treatment, processed, and given stretchability. At this time, the substrate sheet 2 stretched in the conveying direction shrinks in the width direction perpendicular to the conveying direction. When the width of the substrate sheet 2 is 350 mm when it is guided toward one processing roller 12, the width of the substrate sheet 2 after exiting from processing rollers 12 and 14 is 330 mm.

[0044] The temperatures of the outer peripheral surfaces 12s and 14s of processing rollers 12 and 14 are preferably not lower than 10°C and not higher than the melting point temperature of the substrate sheet 2, more preferably not lower than 10°C and not higher than 60°C, and even more preferably not lower than 30°C and not higher than 60°C. For this purpose, at least one processing roller 12, and preferably both processing rollers 12 and 14, are provided with heaters 11h (e.g., Figure 2(As shown). For example, the outer peripheral surface 12s of processing roller 12 is heated by heater 11h, so that its temperature is not lower than 10°C and not higher than 60°C, preferably not lower than 30°C and not higher than 60°C. Optionally, the outer peripheral surfaces 12s and 14s of the two processing rollers 12 and 14 are heated, so that their temperature is not lower than 10°C and not higher than 60°C, preferably not lower than 30°C and not higher than 60°C. By heating the substrate sheet 2 before processing, even when the substrate sheet 2 is conveyed at high speed, it can be ensured that the substrate sheet 2 will not break or be damaged during processing, thereby improving production efficiency. Although the heater is preferably located inside the processing rollers 12 and 14, it can also be located outside them.

[0045] A residual heat heater for preheating the substrate sheet 2 before processing can be set upstream of the processing rollers 12 and 14.

[0046] When conveying the substrate sheet 2, the substrate sheet 2 contacts the outer peripheral surface 12s of one of the processing rollers 12 and is conveyed along the outer peripheral surface before passing between the processing rollers 12 and 14. That is, the conveying path 3 includes a winding portion 12a that follows the outer peripheral surface 12s of the processing roller 12 immediately before the meshing portion 12b.

[0047] The range of the winding portion 12a and the engaging portion 12b, i.e., the angle θ centered on the rotation center line 12x of a processing roller 12, is preferably not less than 180° and not greater than 270°. In this case, the substrate sheet 2 is conveyed a longer distance along the outer peripheral surface 12s of a processing roller 12, and the substrate sheet 2 can be given greater tensile strength when heated by a processing roller 12.

[0048] After passing between a pair of processing rollers 12 and 14, the substrate sheet 2 reaches the second drive roller 18 via guide rollers 33 and 34.

[0049] The second drive roller 18 is rotated in the direction indicated by arrow 18r and conveys the substrate sheet 2 that is in contact with the outer peripheral surface 18s of the second drive roller 18 at the same speed as the circumferential speed of the second drive roller 18.

[0050] Based on the stretching ratio of the substrate sheet 2, the circumferential speed of the second drive roller 18 is made higher than the circumferential speed of the processing rollers 12 and 14, so that the stretched substrate sheet 2 is pulled out from between the processing rollers 12 and 14 in a stable state. For example, the circumferential speed of the second drive roller 18 is 3.2 times the circumferential speed of the processing rollers 12 and 14.

[0051] In this case, since the substrate sheet 2 is no longer restricted in its width direction perpendicular to the conveying direction after it separates from the teeth 13 and 15 of the processing rollers 12 and 14, the substrate sheet 2 shrinks in the width direction between the processing rollers 12 and 14 and the second drive roller 18 when it is pulled out from between the processing rollers 12 and 14. For example, when the width immediately after being discharged from between the processing rollers 12 and 14 is 330 mm, the width at the second drive roller 18 is 290 mm.

[0052] The substrate sheet 2 is laminated onto the additional sheet 4 at the coiling roller 20, thereby forming a composite sheet 6 in which sheets 2 and 4 are bonded together. As shown by arrow 6x, the composite sheet 6 is conveyed to the subsequent process via guide roller 37.

[0053] For example, when hot melt adhesive is applied by the hot melt adhesive application device 40, the substrate sheet 2 is bonded to the attachment sheet 4. In addition to bonding, the substrate sheet 2 and the attachment sheet 4 can also be engaged by means of ultrasound or the like.

[0054] The crimping roller 20 is driven to rotate in the direction indicated by arrow 20r and conveys the substrate sheet 2 that is in contact with the outer peripheral surface 20s of the crimping roller 20 at the same speed as the circumferential speed of the crimping roller 20.

[0055] The circumferential speed of the crimping roller 20 can be the same as or faster than the circumferential speed of the second drive roller 18.

[0056] In the latter case, since the substrate sheet is pulled out from the second drive roller 18 by the curling roller 20, the substrate sheet 2 shrinks in the width direction between the second drive roller 18 and the curling roller 20.

[0057] It is possible to process a single-layer sheet consisting only of the substrate sheet 2 without attaching the additional sheet 4. In this case, there is no need to install components such as the curling roller 20, the rolling roller 22, and the hot melt adhesive application device 40.

[0058] Figure 2 This is a schematic diagram of the sheet processing apparatus 10. (As shown...) Figure 2 As shown, in the sheet processing apparatus 10, the following components are connected to the control section 11 that controls the entire sheet processing apparatus 10, such as a sequencer; a first motor 16m that rotates and drives the first drive roller 16; a second motor 18m that rotates and drives the second drive roller 18; a third motor 12m that rotates and drives the pair of processing rollers 12 and 14; and a first tension T1 (e.g., 16m) applied to the substrate sheet 2 in the conveying direction before the substrate sheet 2 reaches the outer peripheral surface 12s of a processing roller 12. Figure 1 The first detector 17 (as shown) detects the second tension T2 applied to the substrate sheet 2 in the conveying direction after the substrate sheet 2 is discharged from between the processing rollers 12 and 14. Figure 1The second detector 19 (shown) and heater 11h.

[0059] When the first tension T1 is monitored based on the output signal from the first detector 17, the control unit 11 (a) adjusts the rotational speed of the first motor 16m to control the rotation of the first drive roller 16, and / or (b) adjusts the rotational speed of the third motor 12m to control the rotation of a pair of processing rollers 12 and 14, such that the first tension T1 is less than a first predetermined value. In this case, the control unit 11, the first detector 17, the first motor 16m, and / or the third motor 12m act as a tension control device. The first predetermined value may be less than 10% of the breaking load of the substrate sheet 2 in the conveying direction before processing.

[0060] Furthermore, when monitoring the second tension T2 based on the output signal from the second detector 19, the control unit 11 can (a) adjust the rotational speed of the second motor 18m to control the rotation of the second drive roller 18, and / or (b) adjust the rotational speed of the third motor 12m to control the rotation of a pair of processing rollers 12 and 14, such that the second tension T2 is greater than a second predetermined value. Since the second predetermined value only needs to be high enough for the substrate sheet 2 stretched at the meshing portion 12b to be pulled out from between the processing rollers 12 and 14 in a stable state, when the stretch ratio at the meshing portion 12b is high enough, for example, the second predetermined value can be less than 10% of the breaking load of the substrate sheet 2 in the conveying direction before processing, and more preferably less than 5%.

[0061] Figure 3 This is a schematic diagram of the relevant portion near the meshing part 12b of a pair of processing rollers 12 and 14 in the enlarged sheet processing apparatus 10. (See diagram for example.) Figure 3 As shown, the substrate sheet 2, conveyed along the conveying path 3, is conveyed in the direction indicated by arrow 2x while being supported by the teeth 13 of a processing roller 12. When it reaches the meshing portion 12b, the portion of it supported between adjacent teeth 13 is pushed downward toward the interior of a processing roller 12 by the teeth 15 of another processing roller 14. Thus, at the meshing portion 12b, in the conveying direction, tension Td (not shown, the magnitude of which varies depending on the position of the substrate sheet 2 meshing with the teeth 13 and 15 of the processing rollers 12 and 14) is applied to the substrate sheet 2.

[0062] At the winding portion 12a before the meshing portion 12b, the frictional force with the teeth 13 acts on the substrate sheet 2. As the substrate sheet 2 moves away from the meshing portion 12b, that is, as the substrate sheet moves upstream in the conveying direction, the tension of the substrate sheet 2 in the conveying direction decreases.

[0063] Therefore, before the substrate sheet 2 reaches the outer peripheral surface 12s of a processing roller 12, a first tension T1 (such as...) is applied to the substrate sheet 2 in the conveying direction. Figure 1(As shown) can be less than the tension Td applied to the substrate sheet 2 in the conveying direction at the meshing portion 12b. Therefore, the substrate sheet 2 can be stretched under the processing condition that the first tension T1 is less than 10% of the breaking load of the substrate sheet 2 in the conveying direction before processing.

[0064] At the meshing portion 12b, the middle position of a portion of the substrate sheet 2 supported by the adjacent teeth 13 of one processing roller 12 is pushed downward by the teeth 15 of another processing roller 14, thereby generating friction on the substrate sheet 2. Through this friction, after the substrate sheet 2 passes through the meshing portion 12b, the second tension T2 of the substrate sheet 2 in the conveying direction (as shown in the image) is increased. Figure 1 (As shown) is less than the tension Td applied to the substrate sheet 2 in the conveying direction at the meshing portion 12b.

[0065] Furthermore, when the substrate sheet 2 is conveyed along the outer peripheral surface 12s of a processing roller 12 at the winding portion 12a, its contraction in the width direction perpendicular to the conveying direction is limited by the frictional force with the outer peripheral surface 12s of the processing roller 12, so that even if the tension Td of the substrate sheet 2 in the conveying direction exceeds the breaking load at the processing roller 12b, the substrate sheet 2 will not break. Therefore, under processing conditions where the tension Td applied to the substrate sheet 2 at the engagement portion 12b is higher than 90% of the breaking load of the substrate sheet 2 in the conveying direction before processing, stretching treatment can be performed on the substrate sheet 2 without causing any breakage or damage to the substrate sheet 2.

[0066] As described above, by winding the substrate sheet 2 onto a processing roller 12, the substrate sheet 2 can be stretched even when the tension applied to the substrate sheet 2 before and after processing exceeds the conventionally known range (e.g., 10% to 90% of the breaking load). Therefore, the substrate sheet 2 can be given greater tensile strength.

[0067] Experimental Example: An experimental example will be described in which a sheet endowed with tensile properties is processed using the sheet processing apparatus 10 of Example 1.

[0068] When processing rollers 12 and 14 are heated to 35°C-55°C, substrate sheet 2, which is a 350mm wide polyolefin-based stretchable nonwoven fabric, is processed under various conditions combining the circumferential speeds of processing rollers 12, 14, 16, and 18. During processing, the tension of substrate sheet 2 in the conveying direction is measured between the first drive roller 16 and one processing roller 12. Furthermore, the stretch ratio of substrate sheet 2 after processing is determined.

[0069] As a result, when the tension is 0.3N to 7.5N, the stretch ratio of substrate sheet 2 is 1.8 to 2.8 times.

[0070] Furthermore, when a test piece (25 mm wide and 100 mm long) for tensile testing was made from substrate sheet 2 before processing and the tensile test was performed at a force sensor speed of 300 mm / min, the breaking load was 23.2 N (the average of three test pieces). Therefore, before processing, the breaking load of substrate sheet 2 with a width of 350 mm in the conveying direction is (23.2 N / 25 mm) × 350 mm = 325 N.

[0071] Therefore, the tension (0.3N to 7.5N) applied to the substrate 2 with a width of 350mm in the conveying direction before the substrate 2 reaches the outer peripheral surface 12s of a processing roller 12 is 0.9% to 2.3% of the breaking load (325N) of the substrate 2 in the conveying direction before it is processed, and less than 10%.

[0072] Even if the tension applied to the substrate sheet 2 in the conveying direction before it reaches a processing roller 12 exceeds the conventionally known tension limit range (10% to 90% of the breaking load), the substrate sheet 2 can be stretched, and greater tensile strength can be imparted to the substrate sheet 2 compared to when the tension is within the conventionally known tension limit range.

[0073] The sheet manufacturing method of the present invention in Example 1 will be further described below.

[0074] The sheet manufacturing method includes: (i) a conveying step of conveying a substrate sheet 2; and (ii) a processing step of rotary driving a pair of processing rollers 12 and 14, the pair of processing rollers being arranged with a conveying path 3 for conveying the substrate sheet 2, such that when the substrate sheet 2 passes between the processing rollers 12 and 14, the teeth 13 and 15 along the respective outer peripheral surfaces 12s and 14s of the processing rollers 12 and 14 mesh with each other at a certain gap to stretch the substrate sheet 2. In the conveying step, when conveying the substrate sheet 2, the substrate sheet contacts the outer peripheral surface 12s of one of the processing rollers 12 and is conveyed along the outer peripheral surface before passing between the processing rollers 12 and 14, and the tension applied to the substrate sheet 2 in the conveying direction before the substrate sheet 2 reaches the outer peripheral surface 12s of one of the processing rollers 12 is less than 10% of the breaking load of the substrate sheet 2 in the conveying direction before being processed.

[0075] According to the above method, the friction between the substrate sheet 2 and the outer peripheral surface 12s of a processing roller 12 can be utilized to reduce the tension applied to the substrate sheet 2 in the conveying direction as it moves upstream in the conveying direction from the meshing portion where the irregular portions 13 and 15 between processing rollers 12 and 14 engage with each other. Furthermore, the tension applied to the substrate sheet 2 in the conveying direction can be reduced before it reaches the outer peripheral surface 12s of the processing roller 12. In addition, by utilizing the friction between the substrate sheet 2 and the outer peripheral surface 12s of the processing roller 12, the shrinkage of the substrate sheet 2 in the width direction perpendicular to the conveying direction can be limited. Therefore, compared to stretching processing performed at the meshing portion under tension in the conveying direction, greater tensile strength can be imparted to the substrate sheet.

[0076] When the tension of the substrate sheet 2 in the conveying direction is less than 10% of the breaking load of the substrate sheet 2 in the conveying direction before it is processed (before the substrate sheet 2 reaches the outer peripheral surface 12s of a processing roller 12), the shrinkage of the substrate sheet 2 in the width direction can be restricted to a greater extent compared with the case where the tension of the substrate sheet 2 before processing in the conveying direction is not less than 10% of the breaking load of the substrate sheet 2 in the conveying direction before processing. This can give the substrate sheet greater tensile strength.

[0077] Preferably, the sheet manufacturing method further includes a heating step of heating a processing roller 12, such that the temperature of the outer peripheral surface 12s of the processing roller 12 is not lower than 10°C and not higher than 60°C, preferably not lower than 30°C and not higher than 60°C.

[0078] In this case, even if the substrate sheet 2 is transported at an excessively high speed, it can be ensured that the substrate sheet 2 will not break or be damaged during processing.

[0079] Preferably, in the conveying step, the substrate sheet 2 is conveyed along the outer peripheral surface 12s of a processing roller 12 with the rotation center line 12 of the processing roller 12 as the center, within a range of not less than 180° and not more than 270°.

[0080] In this case, the substrate sheet 2 is conveyed a longer distance along the outer peripheral surface 12s of a processing roller 12, and when the substrate sheet 2 is heated by a processing roller 12, the substrate sheet 2 can be heated sufficiently, thereby giving the substrate sheet 2 greater tensile strength.

[0081] In modified embodiment 1, detectors 17 and 19 for detecting the tension of the substrate sheet 2 can also be omitted (e.g., Figure 2(As shown). For example, when the pre-processing tension and post-processing tension of the substrate sheet 2 can be set to predetermined values ​​and the operating conditions of motors 12m, 14m, and 16m that can process the substrate sheet at a desired stretch ratio are known in advance, the pre-processing tension and post-processing tension of the substrate sheet 2 become predetermined values, and the rotational speed, load torque, etc. of motors 12m, 14m, and 16m are controlled. During operation, detectors 17 and 19 do not detect the tension of the substrate sheet 2, so that the substrate sheet can be processed at a desired stretch ratio.

[0082] Example 2: Figure 4 and Figure 5 As shown, the sheet processing apparatus 10a and sheet manufacturing method of the present invention enable an increase in the distance between processing rollers 12 and 14. The sheet processing apparatus 10a of Embodiment 2 has a structure substantially the same as that of the sheet processing apparatus 10 of Embodiment 1. Hereinafter, the differences from the sheet processing apparatus 10 of Embodiment 1 will be mainly described, and the same reference numerals will be used to denote the same elements as those in the sheet processing apparatus 10 of Embodiment 1.

[0083] Figure 4 This is a schematic diagram of the relevant parts of the sheet processing device 10a. Figure 4 (a) is a schematic diagram viewed from the rotation center lines 12x and 14x of the processing rollers 12 and 14. Figure 4 (b) is along Figure 4 (a) is a schematic diagram of line BB observed. For example... Figure 4 As shown, the sheet processing device 10a is equipped with processing roller support mechanisms 11p and 11q and a cylinder 50.

[0084] The processing roller support mechanisms 11p and 11q support processing rollers 12 and 14 and allow the distance between processing rollers 12 and 14 to be variable. Specifically, the bearing portions 13p and 13q of the shaft portions 12p and 12q for rotatably supporting one processing roller 12 are fixed to the main frame 10k of the sheet processing apparatus 10a. The bearing portions 15p and 15q of the shaft portions 14p and 14q for rotatably supporting the other processing roller 14 are supported by the main frame 10k, thereby allowing them to move in the directions indicated by arrows 50a and 50b.

[0085] Cylinder 50 is fixed to the main frame 10k, with rod 52 facing downwards. The bearing portions 15p and 15q of another processing roller 14 are connected to rod 52 of cylinder 50. When rod 52 of cylinder 50 retracts, the other processing roller 14... Figure 4 The position indicated by the solid line moves upward in the direction shown by arrow 50b. Cylinder 50 serves as a processing roller moving device 51 for moving at least processing roller 14 of processing rollers 12 and 14.

[0086] When the substrate sheet is stretched, the rod 52 of the cylinder 50 extends to be stretched, such as... Figure 4 As shown, the corresponding teeth 13 and 15 of the processing rollers 12 and 14 mesh with each other with a certain gap, as... Figure 3 As shown. For example, when rod 52 extends, the bearing portions 15p and 15q of processing roller 14 are prevented from moving against a predetermined portion (not shown) of the main frame 10k, thereby maintaining the distance between processing rollers 12 and 14 at a predetermined value. Thus, the amount of pushing of the substrate sheet during stretching can be set to a predetermined value.

[0087] The amount of material pushed during the stretching process can be defined by the amount of meshing between the teeth 13 and 15 of the processing rollers 12 and 14. In this case, when the amount of material pushed during the stretching process, i.e., the amount of meshing between the teeth 13 and 15 of the processing rollers 12 and 14, is D, the radii of the outer peripheral surfaces 12s and 14s of the processing rollers 12 and 14 (e.g., ...) Figure 1 (As shown) R1 and R2, the distance between the rotation center lines 12x and 14x of processing rollers 12 and 14 is L, and the pushing amount D of the substrate sheet during the stretching process and the meshing amount D between the teeth 13 and 15 of processing rollers 12 and 14 are expressed as the following expression 1:

[0088] D = R1 + R2 - L (Expression 1)

[0089] When the rod 52 of cylinder 50 is Figure 4 When contracting in the direction indicated by the middle arrow 50b, another processing roller 14... Figure 4 The position indicated by the solid line moves upward in the direction shown by arrow 50b, separating from the processing roller 12. This causes the teeth 13 and 15 of the processing rollers 12 and 14 to disengage, thereby creating a gap between the processing rollers 12 and 14, which is beneficial for preparation work, such as inserting the substrate sheet between the processing rollers 12 and 14 before processing.

[0090] When a typical cylinder is used as cylinder 50, rod 52 moves backward when the reaction force overcomes the protruding force to protrude from rod 52. Depending on the weight, width, conveying speed, etc. of the substrate sheet made of nonwoven fabric or the like, the following may occur: the resistance (reaction force) of the substrate sheet overcomes the protruding force of rod 52, thereby increasing the distance L between the rotation center lines 12x and 14x of the processing rollers 12 and 14, and changing the pushing amount D of the substrate sheet, thus causing a change in the stretching amount of the substrate sheet.

[0091] To suppress this change in the stretch of the substrate sheet, each cylinder 50 is equipped with... Figure 5 The locking mechanism 60 shown.

[0092] Figure 5 This is a schematic diagram of the locking mechanism 60. Figure 5(a) shows the unlocked state. Figure 5 (b) shows the locked state. For example... Figure 5 As shown, in the locking mechanism 60, the tapered portion 64 is fixed to the release piston 62, and the release piston 62 and the tapered portion 64 are pushed by the disconnecting spring 66 in the direction indicated by arrow 60a. The tapered portion 64 is a tubular member having a cylindrical outer circumferential surface and a conical inner circumferential surface, the inner diameter of which increases in the direction indicated by arrow 60a. Inside the tapered portion 64, the steel ball 70 is rotatably held by the steel ball holder 72. The brake shoe bracket 74 and the brake shoe 76 are disposed between the steel ball 70 and the rod 52.

[0093] like Figure 5 As indicated by arrow 60p in (a), when compressed air is supplied to the open port 78, the release piston 62 and the cone 64 move in the direction indicated by arrow 60b against the spring force of the disconnecting spring 66, thereby releasing the rod 52. At this time, as indicated by reference numeral A, the ball retainer 72 rests against the housing 68.

[0094] When the air is like Figure 5 (b) As the brakes discharge from the open port 78, as indicated by arrow 60q, the disconnect spring 66 pushes the release piston 62 and the conical portion 64 to move in the direction indicated by arrow 60a. The spring force of the disconnect spring 66 increases due to the wedging effect of the conical portion 64, is transmitted to the steel ball 70, and acts on the brake shoe bracket 74 and the brake shoe 76. Therefore, the lever 52 is tightened and locked under the action of a strong force.

[0095] The locking mechanism 60 serves as an anti-separation device, used to fix the engagement amount D between the irregular portions 13 and 15 of the processing rollers 12 and 14 in a disengaged manner. Since the pushing amount D of the substrate sheet can be kept constant by the locking mechanism 60 during the stretching process of the substrate sheet, the variation in the stretching amount of the substrate sheet caused by differences in the substrate sheet's weight, width, conveying speed, etc., can be controlled.

[0096] In addition to providing a locking mechanism 60 for cylinder 50, it is also possible to... Figure 4 The processing roller holding device 80 is shown.

[0097] The processing roll holding device 80 includes: a detector 82 for detecting the amount of pushing D of the substrate sheet during the stretching process; and a controller 84 for controlling the cylinder 50. For example, the detector 82 is a sensor used to detect the position of another processing roll 14, the position of the bearing portions 15p and 15q of the other processing roll 14, and the extension length of the rod 52 of the cylinder 50.

[0098] The controller 84 calculates the pushing amount D of the substrate sheet during the stretching process based on the detection signal 83 from the detector 82, and controls the cylinder 50 to keep the pushing amount D within a certain range, while monitoring the pushing amount D. For example, when the pushing amount D of the substrate sheet during the stretching process is lower than a predetermined value, the controller 84 sends a control signal 85 to the cylinder 50 to cause the teeth 15 of another processing roller 14 to push the substrate sheet again to the pushing amount of the substrate sheet at the beginning of the stretching process.

[0099] The processing roller holding device 80 serves as an anti-separation device, used to control the engagement amount D between the irregular portions 13 and 15 of the processing rollers 12 and 14 to remain within a predetermined range. Since the amount of pushing of the substrate sheet can be kept substantially constant by the processing roller holding device 80 during the stretching process of the substrate sheet, the variation in the amount of stretching of the substrate sheet caused by differences in the substrate sheet's weight, width, conveying speed, etc., can be controlled.

[0100] The anti-separation device can be configured to fix or control the position of the bearing portions 15p and 15q of the other processing roller 14 (instead of the cylinder 50) within a predetermined range.

[0101] In addition, the following structure can be adopted: processing roller support mechanisms 11p and 11q movably support a pair of processing rollers 12 and 14, a processing roller moving device moves a pair of processing rollers 12 and 14, and an anti-separation device makes the meshing amount D between the irregular portions 13 and 15 of the processing rollers 12 and 14 disengageable and fixed or controlled within a predetermined range.

[0102] The sheet manufacturing method of Example 2 is based on Example 1 with the following added features: processing rollers 12 and 14 are supported such that the distance between processing rollers 12 and 14 can be changed by moving at least processing roller 14. During the processing steps, the meshing amount D between the irregular portions 13 and 15 of processing rollers 12 and 14 is fixed or controlled within a predetermined range.

[0103] In this case, since the distance between the pair of processing rollers 12 and 14 can be increased, it is easy to insert the substrate sheet 2 between the processing rollers 12 and 14 for preparation before starting the stretching process. Since the meshing amount between the irregular portions 13 and 15 of the processing rollers 12 and 14 remains constant or is controlled within a predetermined range during the stretching process, the variation in the stretching amount of the substrate sheet 2 can be controlled.

[0104] As described above, since the tension applied to the substrate sheet 2 in the conveying direction when the substrate sheet 2 passes between the processing rollers 12 and 14 can be increased by the friction between the substrate sheet 2 and the outer peripheral surface 12s of the processing roller 12, the substrate sheet 2 can be given greater tensile strength.

[0105] The present invention is not limited to the above-described embodiments, and various modifications can be made during implementation.

[0106] For example, the irregular portions of a pair of processing rollers 12 and 14 are not limited to spur gear teeth or straight teeth, but can be in various forms, such as helical gears or staggered irregular portions.

[0107] Icon labels:

[0108] 2. Substrate sheet

[0109] 3. Teleportation Path

[0110] 10, 10a Sheet Processing Equipment

[0111] 11. Control Section (Tension Control Device)

[0112] 11h heater

[0113] 11p, 11q processing roll support mechanism

[0114] 12 processing rollers

[0115] 12m third motor (tension control device)

[0116] 12s outer periphery

[0117] 13 teeth (irregular section)

[0118] 14 Processing Rollers

[0119] 14s outer periphery

[0120] 15 teeth (irregular section)

[0121] 16 First drive roller

[0122] 16m First Motor (Tension Control Device)

[0123] 18 Second drive roller

[0124] 18m Second Motor

[0125] 19 Second Detector

[0126] 50 cylinders

[0127] 51 Processing Roller Moving Device

[0128] 60 Locking mechanism (anti-separation device)

[0129] 80 processing roll holding device (anti-separation device)

Claims

1. A method of sheet manufacturing, characterized by: The method steps include: a conveying step of conveying a substrate sheet; and a processing step of rotationally driving a pair of processing rollers arranged to be spaced apart with a conveying path for conveying the substrate sheet so that irregularities formed along respective outer peripheral surfaces of the processing rollers engage with each other with a gap to stretch the substrate sheet as the substrate sheet passes between the processing rollers; wherein, in the conveying step, the substrate sheet is in contact with the outer peripheral surface of one of the processing rollers and is conveyed along the outer peripheral surface before passing between the processing rollers while the substrate sheet is being conveyed; and a tension applied to the substrate sheet in a conveying direction is less than 10% of a breaking load of the substrate sheet in the conveying direction before being processed, before the substrate sheet reaches the outer peripheral surface of one of the processing rollers.

2. The sheet manufacturing method according to claim 1, characterized by: The method steps further include a heating step of heating one of the processing rollers so that the temperature of the outer peripheral surface of one of the processing rollers is not lower than 10°C and not higher than 60°C.

3. The sheet manufacturing method according to claim 1 or 2, characterized by: In the conveying step, the substrate sheet is conveyed along the outer peripheral surface of one of the processing rollers in a range of not less than 180° and not more than 270° with respect to a rotational center line of one of the processing rollers.

4. The sheet manufacturing method according to any one of claims 1 to 3, characterized by: The processing rollers are supported so that the distance between the processing rollers can be changed by moving at least one of the processing rollers, and in the processing step, the amount of engagement between the irregularities of the processing rollers is fixed or controlled within a predetermined range.

5. A sheet processing apparatus characterized by comprising: It includes a pair of processing rollers arranged to be spaced apart with a conveying path for conveying a substrate sheet; and irregularities formed along respective outer peripheral surfaces of the processing rollers engage with each other with a gap when the processing rollers are rotated; wherein, in conveying the substrate sheet, the substrate sheet is in contact with the outer peripheral surface of one of the processing rollers and is conveyed along the outer peripheral surface before passing between the processing rollers; and includes a driving roller provided along the conveying path for bringing the substrate sheet to one of the processing rollers and rotationally driving and feeding out the substrate sheet; and a tension control device that controls the rotation of the driving roller and one or both of the processing rollers so that a tension applied to the substrate sheet in a conveying direction is less than 10% of a breaking load of the substrate sheet in the conveying direction before being processed, before the substrate sheet reaches one of the processing rollers.

6. The sheet processing device of claim 5, wherein: It further includes a heater for a heating step of heating one of the processing rollers so that the temperature of the outer peripheral surface of one of the processing rollers is not lower than 10°C and not higher than 60°C.

7. The sheet processing device according to claim 5 or 6, characterized by: The substrate sheet is conveyed along the outer peripheral surface of one of the processing rollers in a range of not less than 180° and not more than 270° with respect to a rotational center line of one of the processing rollers.

8. The sheet processing device according to any one of claims 5 to 7, characterized by: It further includes: a processing roller support mechanism that supports the processing rollers so that the distance between the processing rollers can be changed; a processing roller moving device that moves at least one of the processing rollers; and a separation prevention device for releasably fixing or controlling the amount of engagement between the irregularities of the processing rollers within a predetermined range.

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