Method for manufacturing a composite sheet

Abstract

To provide a composite sheet manufacturing method that enables quality of product including a composite sheet to be improved and stabilized.SOLUTION: A composite sheet manufacturing method comprises: a step to draw a sheet containing elastic material; a sealing step to form a composite sheet by superimposing a stretchable sheet obtained at the step to draw the sheet on the other sheet and sealing points; a constriction and transportation step to constrict the composite sheet so as to be target stretch magnification while transporting the composite sheet in extended state; an image data acquisition step to obtain image data by imaging a surface of the composite sheet constricted at the constriction and transportation step; a pitch measurement step to measure a pitch width of a seal point formed on the composite sheet at the sealing step on the basis of the image data; a constriction state determination step to determine the constriction state of the composite sheet based on the pitch width; and a constriction control step to control the stretch magnification of the composite sheet based on the determination result at the constriction state determination step.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a composite sheet.

Background Art

[0002] Conventionally, techniques for processing sheets to impart various functions are known. Patent Document 1 describes a method for manufacturing a stretchable sheet using a stretching mechanism including a pair of rolls having tooth grooves that mesh with each other on the outer peripheral surfaces, rotating the rolls, supplying a composite sheet to the meshing portions thereof, and performing stretching processing on the sheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, a manufacturing method is known in which a sheet stretched by a stretching mechanism as described in Patent Document 1 and another sheet are superimposed and joined to form a composite sheet. Further, in some cases, processing such as joining the composite sheet with still another sheet is performed in a line for manufacturing the composite sheet. Since the composite sheet is in an extended state in the manufacturing line, it may be required to suitably control the extended state of the composite sheet in order to improve the processing quality in subsequent processes. For example, when joining a composite sheet and another sheet to form a product, by suitably reducing the degree of elongation of the composite sheet and joining it with another sheet, it is possible to suppress twisting and wrinkles during shrinkage of the product and improve the product function and appearance quality. However, it is inevitable that the expansion and contraction ratio of the sheet changes due to variations in the base material properties of the composite sheet, fluctuations in operation control, or poor rotation of the roll. Therefore, there was room for improvement in stabilizing the production of products containing the composite sheet and enhancing the quality of composite sheet products.

[0005] In view of the above circumstances, the present invention relates to providing a method for manufacturing a composite sheet capable of enhancing and stabilizing the quality of products containing the composite sheet.

Means for Solving the Problems

[0006] The present invention includes a stretching step of a sheet containing an elastic material, a sealing step of overlapping and point-sealing an elastic sheet obtained by the stretching step of the sheet and another sheet to form a composite sheet, a contraction conveying step of conveying the composite sheet in an extended state and contracting the composite sheet to a target expansion and contraction ratio, an image data acquisition step of imaging the surface of the composite sheet contracted in the contraction conveying step to acquire image data, a pitch measurement step of measuring the pitch width of the seal points formed on the composite sheet in the sealing step based on the image data, a contraction state determination step of determining the contraction state of the composite sheet based on the pitch width, and a contraction control step of controlling the expansion and contraction ratio of the composite sheet based on the determination result of the contraction state determination step. A method for manufacturing a composite sheet is provided.

Effects of the Invention

[0007] According to the method for manufacturing a composite sheet of the present invention, the quality of products containing the composite sheet can be enhanced and stabilized.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0009] Hereinafter, a preferred embodiment of the method for manufacturing a composite sheet of the present invention will be described with appropriate reference to the drawings. However, the present invention is not limited to the embodiments exemplified below. In this specification, the machine flow direction and the conveyance direction of the manufacturing apparatus during the manufacture of the composite sheet are referred to as the MD direction (Machine Direction), and the width direction (orthogonal direction) orthogonal to the machine flow direction is referred to as the CD direction (Cross Direction). Further, the direction orthogonal to the MD direction and the CD direction is referred to as the OD direction (Orthogonal Direction). Note that the MD direction, CD direction, and OD direction shown in FIG. 1 described later are three mutually orthogonal axial directions and are common in all the drawings of this specification.

[0010] First, the manufacturing apparatus 100 preferably used in the method for manufacturing a composite sheet of the present invention will be described. As illustrated in FIG. 1, the manufacturing apparatus 100 includes a stretching mechanism 10, a sealing mechanism 20, a shrinkage conveyance mechanism 30, an inspection device 40, and a lighting device 60.

[0011] The stretching mechanism 10 includes a first guide roll 11, a second guide roll 12, and a serrated roll 13. The first guide roll 11 is provided upstream of the serrated roll 13 in the MD direction and has a pair of rolls 111, 112. The roll 111 is connected to a servo motor (a drive source; hereinafter referred to as the first servo motor) (not shown). The roll 111 is rotated by the first servo motor, and accordingly, the roll 112 is rotated. The first guide roll 11 unwinds the sheet A including the stretchable material from the raw material roll R1, supports (clamps) the sheet A before being stretch-processed by the serrated roll 13, and conveys it in the MD direction. Thereby, the first guide roll 11 supplies the sheet A to the serrated roll 13. Note that the MD direction shown in FIG. 1 is the direction in which the sheet A unwound from the raw material roll R1, the sheet B and the composite sheet AB described later are conveyed, and the CD direction orthogonal to the said direction is the width direction of the sheet A, the stretchable sheet A1, the sheet B, and the composite sheet AB.

[0012] The second guide roll 12 is provided downstream of the first guide roll 11 in the MD direction and has a pair of rolls 121, 122. The roll 121 is connected to a servo motor (hereinafter referred to as the second servo motor) (not shown). The roll 121 is rotated by the second servo motor, and accordingly, the roll 122 is rotated. The second guide roll 12 supports (clamps) the stretchable sheet A1 after the sheet A is stretch-processed by the serrated roll 13, pulls it out from the serrated roll 13, and conveys it in the MD direction. The second servo motor is configured to be able to rotate the roll 121 at a roll peripheral speed different from that of the first guide roll 11.

[0013] The tooth groove roll 13 is provided between the first guide roll 11 and the second guide roll 12 in the MD direction and has a pair of rolls 131, 132. Roll 131 is connected to a servo motor (hereinafter referred to as the third servo motor) (not shown). Roll 131 is rotated by the third servo motor, and accordingly, roll 132 is rotated. When rolls 131 and 132 are rotating, the tooth groove roll 13 performs stretching processing on the sheet A supplied to the meshing portions of the respective rolls 131, 132 to impart stretchability. Thereby, the stretchable sheet A1 is formed.

[0014] On the outer peripheral surface of each of rolls 131, 132, as illustrated in FIG. 1, a plurality of teeth T1, T2 and a plurality of tooth grooves are formed. The plurality of teeth T1, T2 and the plurality of grooves extend along the rotation axes of rolls 131, 132. Each of rolls 131, 132 rotates while meshing teeth T1 and T2 with each other when the driving force from the third servo motor is transmitted to the tooth groove roll 131. Note that the extending direction of the tooth grooves is not limited to the aforementioned rotation axis and may be, for example, the roll circumferential direction.

[0015] In the stretching mechanism 10, the supply speed of the sheet A to the tooth groove roll 13 can be controlled by the roll peripheral speed V1 of the first guide roll 11. The delivery speed of the stretchable sheet A1 stretched by the tooth groove roll 13 can be controlled by the roll peripheral speed V2 of the second guide roll 12. By making the roll peripheral speed V2 of the second guide roll 12 faster than the roll peripheral speed V1 of the first guide roll 11 (V2 > V1), a stretching force can be applied to the sheet A and the stretchable sheet A1. That is, the stretching force can be controlled by appropriately setting the difference in roll peripheral speeds (V2 - V1). Thereby, between the first guide roll 11 and the second guide roll 12, a stretching force in the MD direction necessary for stretching processing can be suitably applied to the sheet A.

[0016] The sealing mechanism 20 includes a pattern roll 21 and a seal point forming device 22. The pattern roll 21 is a roll that rotates while supporting the stretchable sheet A1 and another sheet B. As the pattern roll 21 rotates, it unwinds the sheet B from the original roll R2 of the sheet B, and conveys the stretchable sheet A1 that has been stretched by the stretching mechanism 10 in the MD direction in an extended state. The pattern roll 21 according to the present embodiment is a pattern roll having a plurality of protrusions (not shown) formed on the outer peripheral surface, and each of the plurality of protrusions is pressed against the overlapping sheet in which the stretchable sheet A1 and the sheet B overlap. Note that the other sheet B may be one sheet or two or more sheets.

[0017] The seal point forming device 22 sandwiches the stretchable sheet A1 and the sheet B together with the pattern roll 21, and intermittently forms a plurality of seal points P at predetermined intervals in the MD direction and the CD direction with respect to the stretchable sheet A1 and the sheet B conveyed in the MD direction by the pattern roll 21. Specifically, the seal point forming device 22 joins from the opposite side to the portion where the overlapping sheet of the stretchable sheet A1 and the sheet B is pushed up by the protrusions on the circumferential surface of the pattern roll 21, thereby forming a plurality of seal points P (see Fig. 2). The seal points P are the joining points of the stretchable sheet A1 and the sheet B, and a plurality of them are provided at predetermined intervals in the MD direction and the CD direction. In this embodiment, the number of protrusions formed on the pattern roll 21 substantially matches the number of seal points P formed on the composite sheet AB. As a result, the stretchable sheet A1 and the sheet B are intermittently joined (point-sealed) in the MD direction and the CD direction, and a composite sheet AB in which the stretchable sheet A1 and the sheet B are overlapped is formed. The stretchable sheet A1 is in an extended state and is joined to the sheet B at the seal points P. Therefore, between the seal points P in the MD direction, the sheet B is joined with a length corresponding to the length of the stretchable sheet A1 in the extended state. The sealing method by the seal point forming device 22 is not particularly limited and can be various commonly used methods. For example, an ultrasonic welding method or the like is adopted. The shape of the seal points is not particularly limited and can be various shapes. All the patterns on one pattern roll 21 may have the same shape, or patterns with various shapes may be mixed.

[0018] The shrinkage conveying mechanism 30 is a mechanism that shrinks the composite sheet AB with a plurality of seal points P formed thereon in the MD direction and conveys it downstream. The shrinkage conveying mechanism 30 is provided between the sealing mechanism 20 and the inspection device 40 in the MD direction and has a third guide roll 31 and a fourth guide roll 32.

[0019] The third guide roll 31 is provided upstream of the fourth guide roll 32 in the MD direction and has a pair of rolls 311 and 312. Roll 311 is connected to a servo motor (hereinafter referred to as the fourth servo motor) not shown. Roll 311 is rotated by the fourth servo motor, and accordingly roll 312 is rotated. The third guide roll 31 supports (clamps) the composite sheet AB and conveys it in the MD direction. The fourth servo motor is configured to be able to rotate roll 311 at a roll peripheral speed different from the roll peripheral speeds of the pattern roll 21 and the fourth guide roll 32.

[0020] The fourth guide roll 32 is provided downstream of the third guide roll 31 in the MD direction and has a pair of rolls 321 and 322. Roll 321 is connected to a servo motor (hereinafter referred to as the fifth servo motor) not shown. Roll 321 is rotated by the fifth servo motor, and accordingly roll 322 is rotated. The fourth guide roll 32 supports (clamps) the composite sheet AB and conveys it in the MD direction. The fifth servo motor is configured to be able to rotate roll 321 at a roll peripheral speed different from the roll peripheral speed of the third guide roll 31.

[0021] In the contraction conveying mechanism 30 according to the present embodiment, the roll peripheral speed V4 of the fourth guide roll 32 on the downstream side is made slower than the roll peripheral speed V3 of the third guide roll 31 on the upstream side (V3 > V4). By controlling the roll peripheral speed in this way, the conveying speed of the composite sheet AB at the fourth guide roll 32 is made slower than that at the third guide roll 31. Thereby, the composite sheet 12 can be contracted between the third guide roll 31 and the fourth guide roll 32. This contraction relaxes the stretched state of the stretchable sheet A1 when forming the composite sheet AB and makes it a weakly stretched state in a state where the tension accompanying conveyance is acting. Therefore, the composite sheet AB is placed in a state stretched more than the natural state where no tension is applied. Due to this contraction, as illustrated in FIG. 2, as the stretchable sheet A contracts, the sheet B deforms so as to undulate in the MD direction, and the fold W is formed. Along with this, the pitch width H between a plurality of seal points P is reduced in the MD direction and / or the CD direction as compared with the composite sheet AB before contraction. The pitch width H is the distance in the MD direction and the CD direction between the seal points P in a plan view of the composite sheet AB, and may be the distance between the outer sides of the seal points P, the distance between the inner sides, the distance between the outer and inner sides, or the distance between the centroid points of the seal points P. The interval in the MD direction between each point P is referred to as a first pitch width H1, and the interval in the CD direction is referred to as a second pitch width H2 (see FIG. 5). Regarding the contraction of the composite sheet AB by the above control of the roll peripheral speed, the degree of contraction in the MD direction and the degree of contraction in the CD direction also vary depending on the stretching direction by the above-described serrated roll 13, that is, the extending direction of the teeth of the pair of rolls 131 and 132. For example, when the teeth extend in the roll axis direction and the sheet A is stretched in the MD direction, the composite sheet AB contracts more in the MD direction than in the CD direction. Also, when the teeth extend in the roll circumferential direction and the sheet A is stretched in the CD direction, the composite sheet AB contracts more in the CD direction than in the MD direction.

[0022] As illustrated in FIG. 3, the inspection device 40 includes a control device 41, a storage device 42, an imaging device 43, and a display device 44, which are connected via a bus 45. The inspection device 40, each element (e.g., the first to fifth servo motors) constituting the manufacturing device 100, and the lighting device 60 are connected so as to be communicable with each other. This connection may be wireless or wired, and a network such as the Internet or a LAN (Local Area Network) may be interposed. The inspection device 40 is typically a personal computer but is not limited thereto, and may be, for example, an information processing device different from a personal computer. Also, each of the control device 41, the storage device 42, the imaging device 43, and the display device 44 is typically configured integrally but is not limited thereto, and may be configured separately from each other.

[0023] The control device 41 is a device having a function of controlling each element constituting the above-described manufacturing device 100 and a function of processing various data. The control device 41 includes, for example, a processor such as a CPU (Central Processing Unit). Note that the control device 41 may be configured by a single processor or may be configured by a plurality of processors. Also, part or all of the functions of the control device 41 may be realized by hardware such as a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0024] The storage device 42 is one or more memories that store the program PG executed by the control device 41 and the data used by the control device 41 (such as the reference value B, etc.). The storage device 42 is composed of a commonly used recording medium such as a magnetic recording medium or a semiconductor recording medium, for example. The reference value B stored in the storage device 42 is the value of the pitch width H between the seal points P in the MD direction and the CD direction of the composite sheet AB shrunk to the target expansion / contraction ratio. The reference value B preferably has an upper limit value and a lower limit value. The expansion / contraction ratio is the ratio of the length of the composite sheet AB in the MD direction and / or the CD direction after contraction to the length of the composite sheet AB in the MD direction and / or the CD direction before contraction. The storage device 42 may be composed of a combination of multiple types of recording media. Also, the storage device 42 may be a portable storage medium or an external storage medium (such as online storage, etc.) that can communicate with the control device 41.

[0025] The imaging device 43 is a device that uses various members such as an imaging element such as a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge Coupled Device), and a lens for controlling the formation of a subject image on the imaging element, to image the composite sheet AB (the surface of sheet A) shrunk by the shrinkage conveyance mechanism 30 and generate image data. The imaging device 43 is typically a device that captures still images, but is not limited to this, and may be a device that captures moving images, for example.

[0026] The display device 44 is a device that performs display under the control of the control device 41, and includes a display unit (not shown) and an input unit (not shown). The display unit of the display device 41 is various display panels such as, for example, a liquid crystal display panel or an organic EL (electro-luminescence) display panel. The input unit of the display device 41 is various input means such as, for example, a hardware button, a keyboard, a mouse, or a touch panel. For example, the roll peripheral speeds of the first guide roll 11 to the fourth guide roll 32 and the tooth groove roll 13, the conveyance speeds of the sheet A, the stretchable sheet A1, the sheet B, and the composite sheet AB, and the tensions applied to the sheet A, the stretchable sheet A1, the sheet B, and the composite sheet AB are displayed on the display unit of the display device 41. Data regarding these parameters is displayed on the display unit and is input by the user to the input unit and transmitted to the control device 41.

[0027] In the inspection device 40 according to the present embodiment, the control device 41 reads and executes the program PG from the storage device 42, whereby the control device 41 functions as an image data acquisition unit 411, a pitch measurement unit 412, a contraction state determination unit 413, an image processing unit 414, a contraction control unit 415, a seal point measurement unit 416, and a roll state determination unit 417.

[0028] The image data acquisition unit 411 acquires image data generated when the composite sheet AB contracted by the contraction conveyance mechanism 30 is imaged by the imaging device 43. The pitch measurement unit 412 measures the pitch width H between the seal points P formed on the composite sheet AB by the seal mechanism 20 based on the image data.

[0029] The shrinkage state determination unit 413 determines the shrinkage state of the composite sheet AB from the pitch width H measured by the pitch measurement unit 412. The image processing unit 414 performs predetermined image processing on the image data acquired by the image data acquisition unit 411 from the imaging device 43. The shrinkage control unit 415 controls the expansion / contraction magnification of the composite sheet AB based on the determination result of the shrinkage state determination unit 413. The seal point measurement unit 416 measures the number and area of the seal points P of the composite sheet AB based on the image data acquired by the imaging device 43. The roll state determination unit 417 determines the state of the pattern roll 21 that forms the points P on the composite sheet AB based on the measurement result of the point measurement unit 416. In this embodiment, the functions of the control device 41 (image data acquisition unit 411, pitch measurement unit 412, shrinkage state determination unit 413, image processing unit 414, shrinkage control unit 415, seal point measurement unit 416, and roll state determination unit 417) may be realized by a plurality of devices configured separately from each other, or a part or all of the functions of the control device 41 may be realized by a dedicated device.

[0030] The lighting device 60 is a light provided on the downstream side of the shrinkage conveyance mechanism 30 in the MD direction and illuminates the back surface of the sheet B. The lighting / extinguishing of the lighting device 60 is controlled by the control device 41. The light source of the lighting device 60 is not particularly limited, but for example, an LED (Light Emitting Diode) light source is adopted. In this case, the type of the LED light source is not particularly limited, and for example, a bullet type, a FLUX type, a surface mount type (SMD), or a COB (Chip On Board) type is adopted. Also, the color of the light source is not particularly limited and is appropriately determined according to the specifications and uses of the manufacturing apparatus 100, and may be, for example, white, yellow, green, blue, red, or orange, and preferably blue.

[0031] Next, as a preferred embodiment of the method for manufacturing a composite sheet of the present invention, a method for manufacturing a composite sheet using the above-described manufacturing apparatus 100 will be described.

[0032] As illustrated in FIG. 4, the method for manufacturing the composite sheet of the present embodiment includes a stretching step (step St1), a sealing step (step St2), a shrinkage conveying step (step St3), an image data acquisition step (step St4), a pitch measurement step (step St5), a shrinkage state determination step (step St6), and a shrinkage control step (step St8). Hereinafter, each of these steps will be described with appropriate reference to FIGS. 1, 3, and 4.

[0033] [Step St1: Stretching Step] A sheet A including a stretchable material is continuously supplied in the MD direction from the raw material roll R1 by the first guide roll 11 toward the serrated roll 13. The continuously supplied sheet A is stretched by the serrated roll 13 and pulled out from the serrated roll by the second guide roll 12. In this series of processing steps, the conveyance speed and / or tension of the sheet A (and the stretchable sheet A1 after stretching the sheet A) are controlled by the upstream first guide roll 11 and the downstream second guide roll 12, and an elongation force in the conveyance direction is applied to the sheet A (and the stretchable sheet A1 after stretching the sheet A). Specifically, by performing control to make the roll peripheral speed V2 of the second guide roll 12 faster than the roll peripheral speed V1 of the first guide roll 11 (V2 > V1), the sheet A and the stretchable sheet A1 are put in a state of being stretched in the conveyance direction. The stretching of the sheet A in the stretched state is performed by the meshing of the serrations of the pair of rolls 131 and 132 of the serrated roll 13. The stretchable sheet A1 is formed by this stretching. More specifically, the teeth T1 and T2 arranged on the peripheral surfaces of the rolls 131 and 132 are meshed and rotated so as to enter the grooves on the opposing roll peripheral surfaces, and the sheet A between the teeth T1 of the meshed roll 131 and the teeth T1 of the roll 132 is partially stretched. Thereby, a stretchable sheet 12 in which the stretchability of the stretchable material contained in the sheet A is more strongly expressed is formed. The processing using such a serrated roll 13 can be performed, for example, by the methods described in paragraphs

[0012] to

[0040] of JP-A-2007-177384 and paragraphs

[0055] to

[0085] of JP-A-2008-179128.

[0034] [Step St2: Sealing Process] Next, the sealing mechanism 20 unwinds the sheet B from the raw material roll R2. At the same time, the stretchable sheet A1 that has been stretch-processed in the previous step St1 is conveyed in the MD direction in an extended state, and the stretchable sheet A1 and the sheet B are overlapped and point-sealed. For example, as illustrated in FIG. 2, a plurality of seal points P are intermittently formed in the MD direction and the CD direction. Thereby, a composite sheet AB in which the stretchable sheet A1 and the sheet B are joined (point-sealed) via a plurality of seal points P is formed. The sheet B may be one sheet or two or more sheets. In this sealing process, it is preferable that the extended state of the stretchable sheet A1 in the stretching process is maintained. Also, in the [Sealing Process], the point-sealing is preferably ultrasonic welding.

[0035] [Step St3: Shrink Conveying Process] Next, while the shrink conveying mechanism 30 conveys the composite sheet AB formed in the previous step St2 in the MD direction in an extended state, the composite sheet AB is shrunk so as to have a target stretch ratio. This shrinkage is the shrinkage of the composite sheet AB in the MD direction and / or the CD direction. The shrinkage is performed by the control device 41 controlling the roll peripheral speed so that "the roll peripheral speed V3 of the third guide roll 31 > the roll peripheral speed V4 of the fourth guide roll 32". Thereby, the composite sheet AB in an extended state due to the tension acting during conveyance is shrunk so as to have a target stretch ratio (target stretch ratio) and is put into a weakly extended state. Due to this shrinkage, the stretchable sheet A1 shrinks and folds W as illustrated in FIG. 2 are formed on the sheet B. For example, a composite sheet AB having fine folds such as micro pleats can be obtained. Also, due to this shrinkage, the pitch width H between the seal points P in the MD direction and / or the CD direction is reduced from the state in the sealing process.

[0036] As described above, the expansion / contraction ratio is the ratio of the length of the composite sheet AB in the MD direction and / or CD direction after contraction to the length of the composite sheet AB in the MD direction and / or CD direction before contraction. Before contraction refers to the time point when the point seal is formed in the sealing process. After contraction refers to the time point immediately after the contraction conveyance process. While the composite sheet AB is being continuously conveyed, the length before contraction and the length after contraction described above are measured at the pitch width H (H1, H2) (see FIG. 5). Then, in the contraction conveyance process, in order to contract the composite sheet AB to the target expansion / contraction ratio, the theoretical roll peripheral speeds V3 and V4 that achieve the target expansion / contraction ratio are calculated, and the calculated values are set in the control device in advance. By controlling the roll peripheral speeds V3 and V4 according to the setting, the target expansion / contraction ratio is achieved.

[0037] The composite sheet AB that is subjected to the contraction process and conveyed in the [Contraction Conveyance Process] is in an extended state compared to the natural state as a product, but it is contracted to the target expansion / contraction ratio and the extended state is weakened. As a result, it is possible to reduce processing defects and the like in the subsequent processing steps for the composite sheet AB caused by being in the extended state. For example, when performing a step of conveying the composite sheet AB after contraction and joining it to another sheet, since the joining is performed closer to the product state, it is possible to reduce the sagging of the joined portion due to the contraction of the composite sheet AB, and a product with good product functions and appearance can be manufactured. In particular, when forming a joint portion that intersects the extending direction of the fold W, the effect of reducing sagging and improving the appearance is high because sagging is likely to occur due to contraction. However, conventionally, in the conveyed composite sheet AB, the actual expansion / contraction ratio may vary due to the characteristics of the sheet material and other factors, resulting in a deviation from the target expansion / contraction ratio. In contrast, in the present embodiment, the presence or absence of such a deviation is measured and inspected in the following steps, and control is performed to optimize the expansion / contraction ratio. In the subsequent steps, the pitch width H is measured, and the presence or absence of a deviation between the target expansion / contraction ratio and the actual expansion / contraction ratio and the degree of the deviation can be determined.

[0038] [Step St4: Image Data Acquisition Step] Subsequently, the imaging device 43 images the surface of sheet A of the composite sheet AB that was contracted in the previous step St3 at predetermined time intervals to obtain image data. The acquired image data is transmitted to the image data acquisition unit 411. At this time, it is preferable that the edge E in the CD direction of the composite sheet AB is within the viewing angle of the imaging device 43. The image data acquisition unit 411 transmits the image data acquired from the imaging device 43 to the image processing unit 414.

[0039] The image data acquired in the [Image Data Acquisition Step] preferably includes an image processing step in which the image processing unit 414 performs binarization processing based on a predetermined threshold value to generate binarized image data. In the binarization processing, pixels with a luminance of the captured image equal to or higher than the threshold value are binarized to white, and pixels with a luminance lower than the threshold value are binarized to black. Thereby, the discriminability of the seal point P of the composite sheet AB can be improved.

[0040] [Step St5: Pitch Measurement Step] Next, the pitch measurement unit 412 measures the pitch width H (see FIG. 5) between the seal points P formed on the composite sheet AB in the sealing step based on the image data. The pitch measurement unit 412 outputs data regarding this pitch width H to the contraction state determination unit 413. In the example shown in FIG. 6, the pitch width H is the distance between the outer sides of the seal points P. However, the pitch width H may be the distance between the inner sides of the seal points P. The pitch width H is preferably the average value of each pitch width H in the image data. That is, the average value of the pitch width H is calculated for each image data, and a time series group of the average values of the pitch width H corresponding to the image data acquired in time series is obtained. Also, in the pitch measurement step, it is preferable to measure at least one of the first pitch width H1 in the MD direction and the second pitch width H2 in the CD direction between each point P, and it is more preferable to measure both (see FIG. 5).

[0041] In the pitch measurement step, the expansion / contraction ratio can be measured by measuring the pitch width H between the seal points P. Also, since the pitch measurement step is based on the image data of the composite sheet AB that has been contracted through the contraction conveyance step, the pitch width H changes due to contraction, and the above measurement can be performed in a state closer to the product state.

[0042] [Step St6: Contraction state determination step] Next, the contraction state determination unit 413 determines the contraction state of the composite sheet AB based on the data regarding the pitch width H obtained from the pitch measurement unit 412. The contraction state determination unit 413 outputs this determination result to the contraction control unit 415. When the pitch width H is within a predetermined range (YES in step St7), the composite sheet AB is conveyed while maintaining its contracted state and shifted to the next step. On the other hand, when the pitch width H is not within the predetermined range (NO in step St7), the control device 41 executes step St8.

[0043] In the determination of the contraction state of the composite sheet AB, it is preferable to determine whether the pitch width H is within a predetermined range (the allowable range and the value set as the aforementioned reference value B). By thus judging the quality of the contraction state by comparing the pitch width H with the predetermined range, it becomes possible to judge the quality not only in the case of insufficient contraction but also in the case of excessive contraction of the composite sheet AB. The pitch width H in this case may be the pitch width H of each seal point P, or may be the average value of the pitch widths H of the seal points P for each image data.

[0044] Also, in the [contraction state determination step], it is preferable to determine the contraction state of the composite sheet AB based on both the first pitch width H1 in the MD direction and the second pitch width H2 in the CD direction. Thereby, the measurement accuracy of the expansion / contraction ratio of the composite sheet AB that has undergone the contraction step can be improved.

[0045] [Step St8: Contraction control step] Subsequently, the contraction control unit 415 controls the expansion / contraction ratio of the composite sheet AB based on the determination result of the contraction state determination step. As for this control, when the pitch width H is not within a predetermined range, it is preferable to control so as to reduce the difference between the pitch width H and the reference value B. In this case, the pitch width H is preferably the average value for each piece of image data. For example, the difference between the average value of the measured pitch width H (measured value) and the pitch width H (reference value, ideal value) of the target magnification of expansion and contraction is calculated, and fed back to the conveyance system (servo motor) so as to reduce the difference. The reduction of the above difference can be achieved by controlling a drive source (fourth servo motor, fifth servo motor) that drives a mechanism for shrinking the composite sheet AB in the shrink conveyance step. Specifically, when the pitch width H exceeds the upper limit value of the predetermined range, that is, when it is determined that the composite sheet AB is insufficiently shrunk, the difference between the pitch width H and the reference value B is reduced as much as possible (for example, the average value is within the range of ±10% of the upper limit value of the reference value B), the roll peripheral speed of the fifth servo motor that drives the roll 321 is decreased, or the roll peripheral speed of the fourth servo motor that drives the roll 311 is increased. Thereby, the expansion state of the composite sheet AB is further weakened to lower the magnification of expansion and contraction, narrow the pitch width, and make it fall within the reference value B. On the other hand, when the average value of the pitch width H is below the lower limit value of the predetermined range, that is, when it is determined that the composite sheet AB is overly shrunk, the difference between the average value and the reference value B is reduced as much as possible (for example, the average value is within the range of ±10% of the lower limit value of the reference value B), the roll peripheral speed of the fifth servo motor that drives the roll 321 is increased, or the roll peripheral speed of the fourth servo motor that drives the roll 311 is decreased. Thereby, the expansion state of the composite sheet AB is enhanced to increase the magnification of expansion and contraction, widen the pitch width, and make it fall within the reference value B. Thereby, even if there are factors that vary the magnification of expansion and contraction of the composite sheet AB such as variations in the properties of the raw fabric, the magnification of expansion and contraction of the composite sheet AB in the shrinkage step can be favorably maintained and conveyed to the subsequent processing step.

[0046] According to the method for manufacturing a composite sheet of the present embodiment, it becomes possible to convey the composite sheet AB at a desired magnification of expansion and contraction, and in the subsequent processing step, a product using the composite sheet can be favorably manufactured, improving and stabilizing the quality of the product.

[0047] In the method for manufacturing the composite sheet of the present embodiment, it is preferable to perform a seal point measurement step (step St9) and a roll state determination step (step St10) in parallel with the steps of the above-described shrinkage conveyance step (step St3) to shrinkage control step (step St8). These steps St9 and St10 will be described.

[0048] [St9: Seal Point Measurement Step] The point measurement unit 416 measures the number and area of the seal points P in the captured image in the image data acquired in the image data acquisition step (step St4). The point measurement unit 416 outputs this measurement result to the roll state determination unit 417. In the above measurement, it is preferable that the image processing unit 414 provides an inspection window M for the image data and uses the number and area of the seal points P per unit area (see FIG. 7). The area is preferably the sum of the areas of the respective seal points P within the inspection window M. Further, the measurement of the number and area of the seal points P is preferably performed based on the binarized image data. In this step, not only the pitch width H between the seal points P but also the state of the seal points P is measured. Thereby, data serving as a determination material as to whether the seal points P themselves are properly formed, that is, whether the surface state of the pattern roll 21 of the sealing mechanism 20 is proper is acquired.

[0049] [St10: Roll State Determination Step] The roll state determination unit 417 determines the state of the pattern roll 21 that forms the seal points P on the composite sheet AB based on the measurement results obtained by the point measurement unit 416 in the seal point measurement step. By this determination, the surface condition (chipping or wear of the protrusions) of the pattern roll 21 can be timely and inline known from the surface condition of the composite sheet, which affects the seal failure of the product. The surface condition of the pattern roll 21, combined with the measurement and determination for the pitch width H described above, can contribute to the quality improvement and quality stabilization of the composite sheet AB.

[0050] The roll state determination unit 417 outputs the determination result of the roll state to the display device 41. The display device 41 displays the state of the pattern roll 21 determined by the roll state determination unit 417 and notifies the user. Based on the notification, the roll is repaired or replaced to resume the production of the composite sheet AB. In the manufacturing method of the composite sheet AB of this embodiment, by inspecting the surface condition of the pattern roll 21 that performs the point seal and taking measures against it, together with the control of the expansion and contraction ratio based on the pitch width H described above, the quality of the product including the composite sheet AB can be further improved and the quality can be made more stable.

[0051] In the manufacturing method of the composite sheet AB of this embodiment, the materials of the sheet A and the sheet B as the raw material sheets are not particularly limited, and various materials that can impart stretchability to the composite sheet AB can be adopted. For example, the sheet A contains a stretchable material as described above, and may consist only of a stretchable material, or may contain a stretchable material and a non-stretchable material. In particular, when the sheet A contains a stretchable material and a non-stretchable material, the non-stretchable material is stretched by the stretching process described above to reduce the resistance of the stretchable material to stretching, and a high-strength and high-stretch composite sheet AB can be preferably formed. The "stretchability" of the stretchable material referred to here means the property that a material with a length of 100 is stretched to a length of 150 by applying a force in one direction, and then contracts to a length of 100 or more and 110 or less after removing the force. The "non-stretchability" of the non-stretchable material means the property that it cannot be stretched to a length of 150, or even if it can be stretched, it does not contract to a length of 100 or more and 110 or less when the force is removed.

[0052] Sheet A may be a single-layer sheet or a multi-layer laminated sheet. Examples of the single-layer sheet include a sheet obtained by blending elastic fibers and inelastic fibers. Examples of the laminated sheet include a sheet obtained by laminating and joining an inelastic layer containing inelastic fibers to one or both sides of an elastic layer containing elastic fibers. The elastic layer and the inelastic layer are preferably fiber layers such as non-woven fabrics. Further, the elastic layer may be a film-like layer or a net-like layer having elasticity instead of the fiber layer. Another example of the laminated sheet is a sheet in which a plurality of elastic filaments are arranged between a pair of inelastic layers so as to extend in the longitudinal direction (conveying direction) Y of the sheet without crossing each other. Note that the "elasticity" and "inelasticity" mentioned here are synonymous with the definitions of the above-mentioned "stretchability" and "non-stretchability". The stretchable material contained in the raw material sheet 11 can be such elastic fibers, elastic layers, and elastic filaments.

[0053] The elastic fibers are preferably made of an elastic material. Examples of the elastic material include thermoplastic elastomers, rubbers, ethylene-propylene copolymers, etc. Among these, thermoplastic elastomers are preferred in terms of relatively easily forming fibrous elastic bodies. Examples of thermoplastic elastomers include polyurethanes, styrene-based (SBS, SIS, SEBS, SEPS, etc.), olefin-based (copolymers of ethylene, propylene, butene, etc.), vinyl chloride-based, polyester-based, etc. These can be used alone or in combination of two or more.

[0054] In the elastic layer containing the elastic fibers, the content of the elastic fibers in the elastic layer is preferably 50% by mass or more and 100% by mass or less, and more preferably 75% by mass or more and 100% by mass or less. The elastic resin forming the elastic fibers of the elastic layer may contain non-elastic resins such as polyethylene, polypropylene, polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), nylon, organic or inorganic pigments, and various additives (antioxidants, plasticizers, etc.). Further, the first fiber layer may contain non-elastic fibers, organic or inorganic pigments. When the elastic layer is in the form of a film or a net, the above various elastic resins can be used as the forming material of the film or the net.

[0055] Examples of the non-elastic fibers include fibers made of non-elastic resins such as polyethylene, polypropylene, polyester (polyethylene terephthalate, polybutylene terephthalate, etc.), nylon, and biodegradable resins such as polylactic acid. In the non-elastic layer containing the non-elastic fibers, the constituent fibers may be short fibers or long fibers, and may be hydrophilic or water-repellent. Further, core-sheath type composite fibers, split fibers, profiled cross-section fibers, crimped fibers, heat-shrinkable fibers, etc. can also be used. These fibers can be used alone or in combination of two or more.

[0056] The non-elastic layer containing the non-elastic fibers is preferably stretchable. The "stretchable" as used herein includes (a) the case where the constituent fibers themselves stretch, and (b) the case where even if the constituent fibers themselves do not stretch, the fibers joined at the intersections separate from each other, or the three-dimensional structure formed by a plurality of fibers due to the joining of the fibers, etc. structurally changes, or the constituent fibers are torn, or the sag of the fibers is stretched, and the non-elastic layer as a whole stretches. The non-elastic layer may already be stretchable in the state before the above-mentioned stretching process. Alternatively, it may not be stretchable in the state before the stretching process, but may become stretchable by the stretching process. From the viewpoint of improving the transportability of the raw material sheet containing the non-elastic layer, it is preferable that the non-elastic layer is not stretchable in the state before the stretching process.

[0057] The elastic filament can be a filamentous synthetic rubber or natural rubber. Alternatively, it can be obtained by dry spinning (melt spinning) or wet spinning. It is preferable that the elastic filament is directly obtained by melt spinning without once winding it up. The elastic filament is preferably obtained by stretching an unstretched yarn. The elastic filament is preferably formed by stretching in a state where the elastic resin is melted or softened. Thereby, the elastic filament can be accurately joined to the inelastic layer in a non-stretched state. The stretching process when using such an elastic filament can be performed by the method described in paragraphs

[0055] to

[0085] of the aforementioned Japanese Patent Application Laid-Open No. 2008-179128.

[0058] On the other hand, as the sheet B, various sheets that can be sealed to the stretchable sheet A1 can be used without particular limitation. Among them, it is preferable that the stretchability is lower than that of the sheet A.

[0059] As described above, the manufacturing method of the composite sheet of the present invention has been described in terms of embodiments, but the present invention is not limited to the above-described embodiments, and various modifications can be made.

Explanation of Signs

[0060] 10 Stretching mechanism 11 First guide roll 12 Second guide roll 13 Grooved roll 20 Sealing mechanism 21 Roll 22 Seal point forming device 30 Shrinking mechanism 31 Third guide roll 32 Fourth guide roll 40 Inspection device 60 Lighting device A Sheet A1 Stretchable sheet B Other sheet

Claims

1. A stretching step of a sheet including a stretchable material, A sealing step of overlapping the stretchable sheet obtained by the stretching step of the sheet and another sheet and performing point sealing to form a composite sheet, A shrinkage conveying step of conveying the composite sheet in an extended state and shrinking the composite sheet so as to achieve a target stretch ratio, An image data acquisition step of imaging the surface of the composite sheet shrunk by the shrinkage conveying step to acquire image data, A pitch measurement step of measuring the pitch width of the seal points formed on the composite sheet in the sealing step based on the image data, A shrinkage state determination step of determining the shrinkage state of the composite sheet based on the pitch width, A shrinkage control step of controlling the stretch ratio of the composite sheet based on the determination result of the shrinkage state determination step, A method for manufacturing a composite sheet comprising the above steps.

2. In the shrinkage control step, reducing the difference between the pitch width measured by the pitch measurement step and a reference value The method for manufacturing a composite sheet according to Claim 1.

3. In the shrinkage control step, controlling a drive source for driving a mechanism for shrinking the composite sheet in the shrinkage conveying step based on the difference, The method for manufacturing a composite sheet according to Claim 2.

4. In the pitch measurement step, measuring both a first pitch width of the seal points in the conveying direction of the composite sheet and a second pitch width of the seal points in a width direction orthogonal to the conveying direction, In the shrinkage state determination step, determining the shrinkage state of the composite sheet based on both the first pitch width and the second pitch width, The method for manufacturing a composite sheet according to any one of Claims 1 to 3.

5. In the shrinkage state determination step, Determine whether the pitch width of the seal points is within a predetermined range, Based on the determination result, determine the shrinkage state of the composite sheet The method for manufacturing a composite sheet according to any one of claims 1 to 4.

6. Comprising an image processing step of binarizing the image data acquired in the image data acquisition step based on a predetermined threshold value to generate binarized image data The method for manufacturing a composite sheet according to any one of claims 1 to 5.

7. In the stretching step, In the sheet conveyance direction, the conveyance speed and / or tension are controlled by a first guide roll on the upstream side and a second guide roll on the downstream side with respect to the sheet, and an elongation force in the conveyance direction is applied to the sheet, The first guide roll supplies the sheet to a grooved roll provided between the first guide roll and the second guide roll, The supplied sheet is stretched by the grooved roll and pulled out from the grooved roll by the second guide roll The method for manufacturing a composite sheet according to any one of claims 1 to 6.

8. A seal point measurement step of measuring the number and area of seal points of the composite sheet based on the image data, and A roll state determination step of determining the state of a pattern roll for forming seal points on the composite sheet based on the measurement result of the seal point measurement step The method for manufacturing a composite sheet according to any one of claims 1 to 7, comprising

9. In the sealing step, the point seal is ultrasonic welding The method for manufacturing a composite sheet according to any one of claims 1 to 8.

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