Method for inspecting sheet-like material

Abstract

To provide a method for inspecting a sheet-like material which can reduce loss of time or products even when a sheet-like material is slit in a width direction, and can provide the average value of the basic weight of each sheet-like material after slitted.SOLUTION: The method for inspecting a sheet-like material includes: a basic weight measuring step of continuously measuring the basic weight in a longer direction of a sheet-like material while traversing the material in a width direction, thereby obtaining continuous basic weight data connected to the width directional position and the longer directional position; and a slit step of dividing the sheet-like material in the width direction. The average value of the basic weight data of a position to be for a sheet-like material obtained by division in the slit step is obtained from continuous basic weight data connected to the width directional position and the longer directional position, whereby the average value of the basic weight of each sheet-like material is calculated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for inspecting a sheet-like object, characterized in that an average basis weight of the sheet-like object is calculated. [Background technology]

[0002] When continuously manufacturing sheet-like materials such as nonwoven fabrics and paper sheets using synthetic or natural fibers, the basis weight of the sheet-like material is an important item in determining the quality of the product. Normally, in such a basis weight inspection, a length required for the inspection is cut from a sheet-like material that has been wound up in advance for the inspection, and a sample piece is obtained by cutting it to a specified size with a cutter or the like, and the mass of the sample piece is measured and converted into mass per unit area to measure the basis weight (Patent Document 1).

[0003] In response to this, the basis weight of a sheet-like material is continuously measured in the conveying direction during production, and the basis weight data is fed back to a control system to control and monitor the basis weight in real time (Patent Document 2).In this case, a method is also used in which a basis weight measuring device is traversed in the width direction of the sheet-like material (Patent Document 3).

[0004] In order to enhance the functionality of such a sheet-like material, functional materials such as synthetic resins may be applied to a base material to process it into a final sheet-like product. In this case, the product may go through multiple independent lines before being made into a final product, and it is common to inspect the basis weight of the sheet-like material as an intermediate product for each line. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-190317 [Patent Document 2] JP 2004-36048 A [Patent Document 3] JP 2006-64580 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the online basis weight measurement methods as in Patent Documents 2 and 3 are only used for monitoring the basis weight of the sheet-like material during production and for feedback control using the basis weight information, and are not used to obtain basis weight information of the sheet-like material. Therefore, in order to obtain basis weight information of the sheet-like material, the basis weight has to be confirmed by the method as in Patent Document 1, which takes a lot of time and causes product loss.

[0007] In addition, a wide sheet may be produced and then slit in the width direction to produce multiple products simultaneously. In such a case, the basis weight of each slit sheet must be inspected, resulting in significant product loss and time-consuming processes, which can significantly reduce production efficiency.

[0008] Furthermore, when using a method such as that described in Patent Document 1, typically only the basis weight of the beginning and end of the roll wound on each line can be measured, and there is also the problem that it is not possible to measure the basis weight of the entire sheet-like product, which typically has a length of several hundred meters.

[0009] The present invention is devised to solve such conventional problems, and aims to provide a method for inspecting sheet-like materials that can obtain the average basis weight of each sheet-like material with minimal time and product loss, even when the sheet-like material is slit in the width direction. [Means for solving the problem]

[0010] The present invention for solving the above problems is as follows. (1) A method for inspecting sheet-like objects, comprising: a basis weight measurement process for continuously measuring the basis weight in the longitudinal direction of a sheet-like object while traversing the width direction to obtain continuous basis weight data linked to a width direction position and a longitudinal direction position; and a slitting process for dividing the sheet-like object in the width direction, in which an average value of the basis weight data at positions to become each of the sheet-like objects obtained by dividing in the slitting process is calculated from the continuous basis weight data linked to the width direction position and the longitudinal direction position, thereby calculating an average value of the basis weight of each of the sheet-like objects. (2) The method for inspecting a sheet-like material according to (1), further comprising a cutting step of cutting the sheet-like material at the start and end of the portion to be the product to any desired product length. (3) The method for inspecting a sheet-like material according to (1) or (2), wherein the sheet-like material is a laminate having a base material layer and a thin film layer. (4) The method for inspecting a sheet-like material according to (3), wherein the substrate layer is a porous fibrous substrate made of short fibers. (5) The method for inspecting a sheet-like material according to any one of (1) to (4), further comprising an appearance inspection step of detecting defects in the sheet-like material and marking the defects. (6) The method for inspecting a sheet-like material according to (3) or (4), wherein the sheet-like material is manufactured by forming the thin film layer on the base material layer, the basis weight measuring process is carried out before and after forming the thin film layer, and the basis weight of the thin film layer is calculated by taking the difference between the basis weights obtained in each basis weight measuring process. (7) The method for inspecting a sheet-like object according to (3), (4) or (6), wherein the sheet-like object has two or more thin film layers. (8) The method for inspecting a sheet-like material according to any one of (1) to (7), wherein in the basis weight measuring step, the basis weight of the sheet-like material is measured in a non-contact manner. Effect of the Invention

[0011] According to the present invention, even when sheet-like materials are slit in the width direction, it is possible to obtain an average basis weight of each sheet-like material after slitting with little loss of time or product. [Brief description of the drawings]

[0012] [Figure 1] 1 is a side view of a process for measuring basis weight according to the present invention; [Diagram 2] 2 is an example of a traverse configuration of a basis weight measuring device in a basis weight measuring step of the present invention. [Diagram 3] 1 is a side view of an example of a method for inspecting a sheet-like object according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The sheet-like material inspection method of the present invention includes a basis weight measurement process for continuously measuring the basis weight in the longitudinal direction of the sheet-like material while traversing it in the width direction to obtain continuous basis weight data linked to the width direction position and the longitudinal direction position, and a slitting process for dividing the sheet-like material in the width direction.The constituent elements of the method include calculating an average basis weight of each sheet-like material by calculating an average value of the basis weight data at the positions that should become each sheet-like material, obtained by dividing in the slitting process, from the continuous basis weight data linked to the width direction position and the longitudinal direction position.

[0014] The sheet-like material used in the present invention is not particularly limited as long as it can be continuously transported and wound up, and examples of the sheet-like material include a thin film made of synthetic resin, a woven fabric, a nonwoven fabric, and a paper made of fibers such as carbon fiber, metal fiber, and organic fiber, and a laminate or prepreg made by laminating or impregnating these with a synthetic resin.

[0015] Examples of synthetic resins that can be used for lamination or impregnation include thermosetting resins such as epoxy resins, unsaturated polyester resins, phenolic resins, polyimide resins, and melamine resins, and thermoplastic resins such as acrylic resins, polyvinylidene chloride resins, polytetrafluoroethylene resins, and polyvinyl alcohol resins. These resins can be used alone or in combination, and can also be combined with conductive particles or flame retardants, or with solvents or dispersion media such as water or alcohol, or with dispersants such as surfactants.

[0016] Examples of the conductive particles include metal particles, carbon nanotube particles, carbon microcoil particles, graphite particles, graphite, and carbon black.

[0017] The flame retardant may be a phosphorus-based flame retardant, which may contain a phosphorus atom in the molecule, and examples of the flame retardant include organic phosphorus compounds such as phosphate esters, condensed phosphate esters, and phosphazene compounds, and red phosphorus.

[0018] As the surfactant, for example, non-ionic surfactants such as alkylamine oxide, polyvinyl alcohol, polyoxyethylene alkyl ether, and octylphenoxypolyethoxyethanol are preferred because they contain few impurities.

[0019] Examples of carbon fibers include polyacrylonitrile (PAN)-based carbon fibers made from PAN fibers, pitch-based carbon fibers made from petroleum tar or petroleum pitch, cellulosic carbon fibers made from viscose rayon or cellulose acetate, vapor-grown carbon fibers made from hydrocarbons, and graphitized fibers of these.

[0020] Examples of metal fibers include fibers made of metals such as iron, gold, silver, copper, aluminum, brass, and stainless steel.

[0021] Examples of the organic fibers include fibers made of organic materials such as polyester, polyamide, polyolefin, and polyacrylonitrile.

[0022] It is preferable to form the sheet-like material as a laminate having a thin film layer on a substrate layer made of the above-mentioned film, woven fabric, nonwoven fabric or paper made of fibers, etc., in that the sheet-like material can have high functionality.

[0023] In addition, it is preferable to use a porous substrate using short fibers as the substrate layer, since it is expected that the sheet-like material will have high functionality. The average fiber length of the short fibers is preferably within a range of 3 to 20 mm. When the average fiber length is 3 mm or more, the mechanical strength, electrical conductivity, and thermal conductivity are excellent. Furthermore, when the average fiber length is 20 mm or less, the dispersion of the fibers is improved when the sheet is made into a sheet using a papermaking method, and a homogeneous paper or nonwoven fabric can be obtained.

[0024] The basis weight measuring process of the present invention will now be described. The basis weight measuring process is not limited to any particular configuration as long as it can continuously measure the basis weight in the longitudinal direction of the sheet-like material while traversing the width direction, but may, for example, be configured to include a basis weight measuring device that can continuously measure the basis weight of the conveyed sheet-like material by contact or non-contact means, and a scanning means that reciprocally scans the basis weight measuring device in the width direction of the sheet-like material.

[0025] It is preferable to use a device that can measure the basis weight of a sheet-like material without contact (a non-contact device) as the basis weight measuring device, because it is possible to measure the basis weight during production and because it is a non-destructive test, it is possible to reduce product loss.

[0026] Examples of non-contact devices include those that are composed of an electromagnetic wave generator that generates electromagnetic waves such as visible light, radiation such as X-rays, β-rays, γ-rays, or infrared rays, and an electromagnetic wave detector that detects the electromagnetic waves. In such basis weight measuring devices that use electromagnetic waves, the reflected wave when the electromagnetic waves are irradiated onto a sheet-like material is detected, and data such as the phase difference with the transmitted wave, the amount of attenuation, and the amount of fluorescent X-rays emitted from the sheet-like material is detected, and correction and integration calculations are performed to convert the calculation results into basis weight based on a calibration curve created in advance, thereby measuring the basis weight.

[0027] In addition, it is preferable to use a production management system that is capable of synchronizing and comparing the above-mentioned basis weight data with the elapsed time from the start to the end of production, the conveying speed, the traverse speed of the basis weight measuring device, etc., because this makes it possible to obtain basis weight data linked to the position of each measurement field of view from the start to the end of processing in a state linked to the production process and situation.

[0028] With the above-described configuration, the basis weight of a traveling sheet-like material can be measured quickly and continuously over its entire width, and the basis weight of the product can be accurately determined over its entire area. This allows for a significant improvement in productivity compared to conventional sampling inspections, thereby achieving improved product quality and reduced production costs for the sheet-like material.

[0029] Here, "continuous measurement" means that the basis weight is measured while the sheet is transported at an arbitrary speed from unwinding to winding. Note that the transport speed may be changed or the transport may be stopped temporarily during the transport of the sheet, and in this case, the basis weight measurement and traversal are also stopped.

[0030] Here, the width direction is a direction perpendicular to the conveying direction of the sheet-like material. By traversing so that the measurement field of view of the basis weight measuring device includes the locations of each sheet-like material after slitting, basis weight information linked to the width direction position and the longitudinal direction position for each sheet-like material after slitting can be obtained with one measuring device. In addition, traversing to include the locations that will become both ends of each sheet-like material after slitting is preferable because basis weight information for the entire width of each sheet-like material after slitting can be obtained.

[0031] When inspecting a laminate having a base layer and a thin film layer by the inspection method of the present invention, it is a preferred embodiment to have the above-mentioned basis weight measurement step before and after the step of forming the thin film layer. With this configuration, the basis weight of the thin film layer can be calculated by taking the difference between the basis weight before and after the step of forming the thin film layer. When forming a plurality of thin film layers, a basis weight measurement step may be provided before and after each step of forming the thin film layer.

[0032] The faster the traverse speed in the width direction of the basis weight measuring device, the more the number of measurement points at each width direction position increases and the more accurate the average basis weight becomes. However, due to constraints on the mechanical configuration, the ratio of the conveying speed to the traverse speed is preferably 1:1 to 20:1, and more preferably 1:1 to 11:1.

[0033] The method for producing a sheet-like material of the present invention includes a slitting step for dividing the sheet-like material into pieces of any width in the width direction. The slitting step may be on the same line as the line including the basis weight measuring step, or may be on a line separate from the line including the basis weight measuring step.

[0034] The information on the slitting positions and the width of the sheet-like material after slitting is collated with the continuous basis weight data associated with the widthwise and longitudinal positions obtained in the basis weight measurement process, and the average basis weight data of the positions to become each sheet-like material is calculated, thereby making it possible to calculate the average basis weight of each slit sheet-like material. It is also preferable to perform the above process in a unified production management system.

[0035] In one preferred embodiment of the method for producing a sheet-like material of the present invention, the method further includes a cutting step of cutting the sheet-like material at the start and end of the product to obtain a desired product length. The cutting step may be located on the same line as the slitting step, or may be located on a separate line from the slitting step.

[0036] Even when the cutting process is included, the average basis weight for the product length can be calculated by calculating the average basis weight for the continuous basis weight data obtained in the basis weight measurement process for the section from the start to the end of the product. In this case, the information on the start and end positions can be calculated from information on the conveying speed and the elapsed time from the start to the stop of conveying when cutting the sheet-like material at the corresponding positions. Since the processing of the above information is generally complicated, it is preferable to manage and calculate it centrally in a production management system.

[0037] In one preferred embodiment of the method for producing a sheet-like material of the present invention, the method further includes an appearance inspection step of detecting defects in the sheet-like material and marking the defects. Examples of the defects include foreign matter attached to the sheet-like material, scratches, cloudiness, surface irregularities, holes, and other defects that affect the quality and appearance of the product. The defects are detected visually, optically, or by radiation such as X-rays, and are marked by a marking device such as an inkjet or laser so that the position of the defect can be identified. From the viewpoints of productivity and equipment costs, it is preferable that the device for detecting the defects and the marking device are arranged on the same line.

[0038] Preferred embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these embodiments. Furthermore, the descriptions of preferred devices and their configurations, as well as numerical ranges, in the descriptions of the individual embodiments, can also be construed as descriptions of the inspection method of the present invention as a generic concept.

[0039] An example of the basis weight measuring process in the sheet-like material inspection method of the present invention is shown in Fig. 1. In Fig. 1, the basis weight measuring process 5 is made up of a basis weight measuring device 2 that measures the basis weight of a sheet-like material 1 that runs continuously in a conveying direction 7, a rotary encoder 3 that obtains information on the conveying speed, and a control unit 4 that controls these, and the control unit 4 is connected to a production management system 6.

[0040] An example of a basis weight measuring device 2 is a configuration consisting of an electromagnetic wave generator that irradiates electromagnetic waves onto the sheet-like material 1, a detector that detects the electromagnetic waves (transmitted waves) that have passed through the sheet-like material 1, and a shielding plate for uniformly capturing the transmitted waves.

[0041] The data detected by the basis weight measuring device 2 is subjected to various calculations such as correction calculations and integration calculations in the control unit 4 to be converted into basis weight data, which is then input into the production management system 6.

[0042] In addition, the conveying speed of the sheet-like material 1 read by the rotary encoder 3, the traverse speed and traverse width information input in advance into the production management system 6 are synchronized with the elapsed time from the start of production to the end of production, which is centrally managed by the production management system 6, thereby linking the widthwise position and the longitudinal position to the basis weight data.

[0043] An example of the traverse configuration of the basis weight measuring device in the basis weight measuring step of the present invention is shown in Figure 2. The basis weight measuring device 2 is traversed on a rail installed in the width direction of the sheet-like material 1 by a traverse driving device 8.

[0044] An example of the method for inspecting a sheet-like material of the present invention is shown in FIG. 3. In FIG. 3, there are basis weight measurement steps 5a and 5b before and after the coating step 10 for forming a thin film layer. In the basis weight measurement step 5a, the basis weight of the substrate before the thin film layer is formed is measured in the same manner as in the example of FIG. 1, and then the basis weight of the sheet-like material 1 including the thin film and the substrate after the thin film layer is formed is measured in the basis weight measurement step 5b in the same manner as in the example of FIG. 1. Continuous basis weight data measured in the basis weight measurement steps 5a and 5b are input into the production management system 6, and the basis weight of the thin film layer can be calculated by subtracting the basis weight measured in the basis weight measurement step 5a from the basis weight measured in the basis weight measurement step 5b. The longitudinal position information in the basis weight measurement step 5b is calculated using information on the conveying speed acquired by the rotary encoder 3 in the basis weight measurement step 5a.

[0045] The coating process 10 is not particularly limited as long as it can uniformly coat the substrate with the width of the product, and a die coater, roll coater, comma coater, etc. can be used, but a die coater is preferable from the viewpoint of coating accuracy. In addition, there is no particular limit to the composition and coating amount forming the thin film layer as long as they can be measured in the basis weight measurement process 5b.

[0046] The basis weight measuring step 5b is followed by a slitting step 11 in which slits are made along the longitudinal direction. In the slitting step 11, it is preferable that the sheet can be slit to any width, and the actual slitting width is preferably 1 / 10 to 9 / 10 of the total width of the sheet-like material 1 before slitting. If the sheet is slit finer than 1 / 10, the number of points corresponding to the slitted sheet-like material among the measurement points of the basis weight measured in the basis weight measuring steps 5a and 5b will be reduced, and this may result in a deterioration in the accuracy of the average basis weight.

[0047] Moreover, data on the width of each product slit in the slitting process 11 is input into the production control system 6.

[0048] In addition, after the slitting process 11, a cutting process 12 is included. In the cutting process 12, when the start end of the portion that will become the product in the longitudinal direction reaches the cutting process 12, conveyance is temporarily stopped, the sheet-like material 1 is cut at the start end of the portion that will become the product, and the start end is wound around a core such as a paper tube set in a winding device 13. Thereafter, conveyance is resumed and the sheet-like material 1 is wound into a roll. Conveyance is stopped when the sheet-like material 1 has been wound to a predetermined product length, and the sheet-like material 1 is cut at the end of the portion that will become the product to form a product roll.

[0049] Information on the positions of the start and end of the product roll cut in the cutting process 12 is input into the production control system 6.

[0050] After the slitting process 11, an appearance inspection process may be provided in which defects in the sheet-like material 1 slit in the slitting process 11 are detected and the defects are marked.

[0051] By comparing the continuous basis weight data linked to the widthwise and longitudinal positions measured in the basis weight measurement process 5b with the traverse speed, traverse width information, elapsed time from the start of production to the end of production, and conveying speed information of the basis weight measurement process 5b inputted into the production management system 6, the average basis weight of each sheet-like material after slitting can be obtained.

[0052] In addition, by comparing the continuous basis weight data of the thin film layer calculated from the continuous basis weight data in the basis weight measurement processes 5a and 5b with the various data mentioned above inputted into the production management system 6, it is also possible to obtain an average basis weight of the thin film layer in each sheet-like material after slitting.

[0053] In addition, by comparing the information on the positions of the start and end of the product rolls produced in the cutting process 12, the average basis weight of the sheet-like material in each product roll and the average basis weight of the thin film layer can also be obtained.

[0054] In FIG. 3, the basis weight measuring steps 5a and 5b, the slitting step 11 and the cutting step 12 are arranged on one line, but each of the steps may be arranged on a separate line.

[0055] In addition, two or more thin film layers may be formed in the coating process 10. In this case, the compositions of the respective thin film layers may be the same or different. In addition, multiple coating processes 10 may be provided for each thin film layer, or multiple layers may be coated by passing the same coating process 10 multiple times. When multiple coating processes 10 are provided, they may be provided on the same line or on separate lines. When they are provided on separate lines, a cutting process 12 may be provided on each line. In this case, information on the cutting positions in each cutting process 12 must be input into the production management system 6 and taken into consideration when calculating the average basis weight of each product roll, etc. [Explanation of symbols]

[0056] 1. Sheet-like object 2, 2a, 2b Basis weight measuring device 3 Rotary Encoder 4, 4a, 4b Control section 5, 5a, 5b Basis weight measurement process 6 Production Management System 7 Conveying direction 8 Traverse drive equipment 9 Scanning trajectory 10 Coating process 11 Slitting process 12 Cutting process 13 Winding device [Industrial Applicability]

[0057] The present invention relates to a method for inspecting a sheet-like material, which accurately calculates the average basis weight of the sheet-like material after slitting based on continuous basis weight data linked to widthwise and longitudinal positions.

Claims

1. The method for inspecting sheet-like objects includes a basis weight measurement process for continuously measuring the basis weight in the longitudinal direction of the sheet-like object while traversing the width direction to obtain continuous basis weight data linked to the width direction position and the longitudinal direction position, and a slitting process for dividing the sheet-like object in the width direction, and calculates an average basis weight of each of the sheet-like objects by calculating an average value of the basis weight data at the positions that should become each of the sheet-like objects, obtained by dividing in the slitting process, from the continuous basis weight data linked to the width direction position and the longitudinal direction position.

2. 2. The method for inspecting a sheet-like material according to claim 1, further comprising a cutting step of cutting the sheet-like material at a start end and an end end of a portion to be a product to a desired product length.

3. 2. The method for inspecting a sheet-like object according to claim 1, wherein the sheet-like object is a laminated material having a base material layer and a thin film layer.

4. 4. The method for inspecting a sheet-like object according to claim 3, wherein the substrate layer is a porous fibrous substrate made of short fibers.

5. 2. The method for inspecting a sheet-like object according to claim 1, further comprising an appearance inspection step of detecting defects in the sheet-like object and marking the defects.

6. The method for inspecting a sheet-like material according to claim 3, wherein the sheet-like material is manufactured by forming the thin film layer on the base material layer, the basis weight measurement process is performed before and after forming the thin film layer, and the basis weight of the thin film layer is calculated by taking the difference between the basis weights obtained from each basis weight measurement process.

7. The method for inspecting a sheet-like object according to claim 3, wherein the sheet-like object has two or more thin film layers.

8. The method for inspecting a sheet-like material according to claim 1 , wherein the basis weight measuring step measures the basis weight of the sheet-like material in a non-contact manner.

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