Method and apparatus for evaluating a laminate, and method and apparatus for manufacturing a laminate

Abstract

A method of evaluating a laminate formed by joining two or more layers, the method including: an image acquisition step of acquiring a two-dimensional image of the laminate; a detection step of detecting a gas pocket corresponding region from the two-dimensional image; a characteristic value acquisition step of calculating a characteristic value associated with an area of the gas pocket corresponding region; and an evaluation step of evaluating the laminate based on the characteristic value.

Description

Technical Field

[0001] This invention relates to a method and apparatus for evaluating laminates, and a method and apparatus for manufacturing laminates. Background Technology

[0002] In applications such as vehicle airbags, outdoor products, and clothing, a type of laminate is known, which is formed by bonding together multiple layers of sheet-like materials. For example, Patent Document 1 discloses a fiber gas bag material in which a thin film of airtight material is applied to the wall portion of fabric layer 14 in a manner that covers the entire surface.

[0003] <Prior art documents>

[0004] <Patent Documents>

[0005] Patent Document 1: European Patent Application Publication No. 1044803 Summary of the Invention

[0006] <Problem to be solved by this invention>

[0007] In applications of the laminates described above, exemplified by the gasbag (air bladder) disclosed in Patent Document 1, high quality is typically required. Therefore, a method is needed to accurately and easily evaluate various properties related to the quality of the laminate. For example, high strength is generally required for the laminate, and the strength of the laminate largely depends on the bonding strength between the layers constituting the laminate; thus, a method is needed to accurately and easily evaluate properties such as bonding strength.

[0008] However, conventional methods for evaluating the properties of laminates formed by bonding two layers are often cumbersome. For example, the bonding strength of a laminate formed by bonding two layers is actually evaluated by measuring the load (peel force) applied when one layer is torn from the other. In such conventional methods, mechanical units for breaking the laminate (in the example of evaluating bonding strength above, the unit that tears the layers apart) are required, and the procedures are usually quite complex.

[0009] In view of the above problems, one aspect of the present invention is to solve the problem of accurately and easily evaluating laminates formed by bonding two or more layers.

[0010] <Methods for solving problems>

[0011] To address the aforementioned problems, one aspect of the present invention provides a method for evaluating a laminate, which is formed by bonding two or more layers together. The method includes: an image acquisition step of acquiring a two-dimensional image of the laminate; a detection step of detecting a region corresponding to an air bag from the two-dimensional image; a characteristic value acquisition step of calculating a characteristic value associated with the area of ​​the region corresponding to the air bag; and an evaluation step of evaluating the laminate based on the characteristic value.

[0012] <The Effects of the Invention>

[0013] According to one aspect of the present invention, it is possible to accurately and easily evaluate laminates formed by bonding two or more layers. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a manufacturing apparatus for a laminate according to an embodiment of the present invention.

[0015] Figure 2 It is a cross-sectional photograph of a laminate containing air bags.

[0016] Figure 3 This is a schematic diagram of an evaluation device for a laminate according to an embodiment of the present invention.

[0017] Figure 4 This is a functional configuration diagram of an evaluation device for a laminate according to an embodiment of the present invention.

[0018] Figure 5 This is an example of a two-dimensional image of the obtained stacked volume.

[0019] Figure 6 This is an example of a binarized image generated based on an acquired two-dimensional image.

[0020] Figure 7 The graphs show the relationship between porosity and bonding strength for Examples 1-1 to 1-3.

[0021] Figure 8 The graphs show the relationship between porosity and bonding strength for Examples 2-1 and 2-2.

[0022] Figure 9 The graphs for Examples 3-1 and 3-2 show the correlation between porosity and bonding strength.

[0023] Figure 10 This is a cross-sectional image of the laminate obtained in Example 4-1.

[0024] Figure 11 Based on Figure 10 A binarized image generated from the cross-sectional image.

[0025] Figure 12 This is a cross-sectional image of the laminate obtained in Example 4-2.

[0026] Figure 13 Based on Figure 12 A binarized image generated from the cross-sectional image. Detailed Implementation

[0027] One embodiment of the present invention is a method for evaluating a laminate, which is formed by bonding two or more layers together. The method includes: an image acquisition step, acquiring a two-dimensional image of the laminate; a detection step, detecting a region corresponding to an air bag from the two-dimensional image; a characteristic value acquisition step, calculating a characteristic value related to the area of ​​the region corresponding to the air bag; and an evaluation step, evaluating the laminate based on the characteristic value.

[0028] In addition, one embodiment of the present invention is an apparatus for evaluating a laminate formed by bonding two or more layers. The apparatus includes: an image acquisition unit for acquiring a two-dimensional image of the laminate; a detection unit for detecting an area corresponding to an air bag from the two-dimensional image; a characteristic value acquisition unit for calculating a characteristic value related to the area of ​​the area corresponding to the air bag; and an evaluation unit for evaluating the laminate based on the characteristic value.

[0029] The laminated body evaluated in this embodiment is a sheet-like structure formed by bonding two or more layers together. Preferably, at least one of the two or more layers constituting the laminated body is flexible, and preferably all layers are flexible. Furthermore, it is preferable that the laminated body as a whole is flexible and airtight. For example, the laminated body may be configured such that one of the two or more layers is a base fabric, and another is a polymer layer. In this case, it is preferable that the base fabric is the outermost layer (the frontmost layer or the backmost layer) of the laminated body. The laminated body of this embodiment is suitable for use in vehicle airbags, outdoor products, clothing, packaging materials, etc., and is particularly suitable as a material for vehicle airbags.

[0030] When a base fabric and a polymer layer are laminated to form a laminate, the base fabric functions as a support to ensure the strength of the laminate. The base fabric is a sheet-like structure containing fibers and can be woven fabric, woven cloth, nonwoven fabric, etc. The base fabric can be sewn on entirely or partially. There are no particular limitations on the types of fibers contained in the base fabric; it can be synthetic fibers, natural fibers, regenerated fibers, semi-synthetic fibers, inorganic fibers, and combinations thereof (including blends and weaves).

[0031] On the other hand, the polymer layer is preferably a flexible layer mainly comprising a polymer, and imparts airtightness to the laminate formed by bonding it with the base fabric. There are no particular limitations on the polymer used, including resins, rubbers, and so-called elastomers.

[0032] When the laminate consists of two layers, for example, a base fabric and a polymer layer can be prepared separately, overlapped one on top of the other, and bonded together by heating and / or pressurizing. In this case, at least a portion of the base fabric and / or polymer layer can be melted or softened to bond them together. An adhesive can be used as an auxiliary agent when bonding the two layers. Alternatively, the laminate can be bonded using an adhesive regardless of whether heating and / or pressurizing are applied. The above manufacturing process is the same for laminates consisting of three or more layers.

[0033] Figure 1 An example of a laminate manufacturing apparatus 100 and a bonding device 20 included in the manufacturing apparatus 100 is shown. Figure 1 The illustration shows an example of fabricating a laminate by bonding a base fabric and a polymer layer. Specifically, in the bonding apparatus 20, the pre-wound base fabric 4 and polymer layer 1 are unfolded, overlapped, and conveyed, and then bonded together in the bonding apparatus 20. The overlapping base fabric 4 and polymer layer 1 are heated and / or pressurized in the bonding apparatus 20 by a heating unit 22 and a pressing unit (such as a clamping roller) 23. It should be noted that although the heating unit 22 and the pressing unit 23 are configured separately in the illustrated example, the same components can also be used for heating and pressing.

[0034] Laminates can also be manufactured using methods other than those described above. Laminates can be manufactured by feeding polymer layers, extruded into a layered shape by an extruder or similar device, onto a base fabric in a relatively soft state before cooling, and then heating and / or pressurizing as needed. Alternatively, they can be manufactured by placing a base fabric manufacturing apparatus (loom, etc.) and a polymer layer manufacturing apparatus (extruder, etc.) adjacent to each other, feeding freshly extruded polymer layers onto the freshly produced base fabric, and then heating and / or pressurizing as needed. Furthermore, they can be manufactured by bonding the base fabric and / or polymer layers together with an adhesive without melting or softening the base fabric and / or polymer layers.

[0035] Since the aforementioned laminates are typically used in final products with high quality requirements, it is important to accurately and easily evaluate various quality-related properties according to the intended use of the laminate. The properties evaluated here can be resistance to external physical or chemical factors such as pressure, impact, scratches, temperature, and humidity, and related characteristics, such as pressure resistance (more specifically, pressure at break, internal pressure retention, etc.), flame retardancy, scratch resistance, abrasion resistance, heat resistance, moisture resistance, and weather resistance. Furthermore, depending on the intended use of the laminate, strength, especially bonding strength, internal pressure retention characteristics, air permeability, air tightness, liquid tightness, robustness, and long-term reliability can be evaluated.

[0036] However, traditional evaluation methods for laminates often involve assessing the laminate by applying external physical or chemical factors, requiring specialized instruments or apparatus, and are cumbersome or time-consuming. For example, since the interlayer bonding strength in a laminate is significantly related to the quality of the final product manufactured using the laminate, and its evaluation is particularly important, there is a desire for an accurate and convenient method to evaluate bonding strength. However, traditional methods for evaluating bonding strength measure the peel force when the bonded layers are torn apart (breaking the interlayer bond), which requires not only mechanical units for tearing but also involves a complex tearing process.

[0037] Furthermore, since traditional evaluation methods often involve damaging the laminate as described above, increasing the number of samples to improve inspection accuracy reduces inspection efficiency during laminate quality checks. Additionally, it is difficult to perform traditional evaluations online and feed the results back to the bonding device. Therefore, it is impossible to modify or adjust the bonding conditions to suitable conditions during laminate manufacturing.

[0038] In response, the inventors have discovered a method for evaluating the properties of a laminate by acquiring and analyzing a two-dimensional image of the laminate. According to this embodiment, the properties of the laminate can be evaluated accurately and easily. Furthermore, this method enables non-destructive evaluation of the laminate. Moreover, since online evaluation is also possible, the laminate can be manufactured while receiving evaluation results.

[0039] The following describes the steps for evaluating the characteristics of a two-dimensional image based on a laminate. For example, in the case where the laminate is formed by bonding a base fabric and a polymer layer, sometimes the two layers are not tightly bonded at the bonding portion between the base fabric and the polymer layer, and instead, there is local separation between the surfaces of the base fabric and the polymer layer. That is, sometimes a portion containing air or other gas is formed between the two layers. In this specification, such a portion is referred to as an air pocket or void. This air pocket may form when at least one of the two layers has an uneven surface, at least one of the two layers is flexible, or the two layers are bonded with a small amount of adhesive.

[0040] As an example, Figure 2 A cross-sectional photograph is shown showing a laminate formed by bonding polymer layers to a base fabric, cut in a direction orthogonal to the surface direction of the laminate (along the surface direction of the laminate). Figure 2 In the laminated body, a polymer layer 1 is adhered to a plain-weave base fabric 4, which is woven in a manner that causes multiple single fiber bundles to extend in mutually orthogonal directions. Figure 2 As shown, near the edge of the fiber bundle of the base fabric 4, there is a region where the base fabric 4 is separated from the polymer layer 1, namely the air bag AP.

[0041] The inventors have discovered that the presence of air pockets affects more than one property of the laminate, and that there is a correlation between the proportion of air pockets and more than one property of the laminate. For example, a smaller proportion of air pockets indicates improved resistance to external physical or chemical factors, and properties associated with this resistance tend to improve. For instance, a smaller proportion of air pockets indicates that the laminate is less flammable, thus improving flame retardancy. A smaller proportion of air pockets indicates that the layers are less likely to tear apart, thus improving abrasion resistance and scratch resistance. Furthermore, a smaller proportion of air pockets indicates that air permeability tends to decrease. In particular, the inventors have discovered a good correlation between the proportion of air pockets and bonding strength, and a good correlation between the proportion of air pockets and internal pressure retention rate. Furthermore, by utilizing this correlation, it is possible to obtain a two-dimensional image of the laminate, detect the area corresponding to the air pockets (also called the air pocket corresponding area), calculate the characteristic value associated with its area, and determine more than one property of the laminate based on this characteristic value. The region corresponding to the aforementioned air bag can be easily detected based on the optical features of the acquired image.

[0042] Figure 3 A schematic diagram of the evaluation apparatus 10 used for performing the evaluation method of this embodiment is shown. Figure 3The evaluation device 10 shown is capable of acquiring, analyzing, and evaluating two-dimensional images of the laminate 5 formed by bonding the base fabric 4 and the polymer layer 1. For example... Figure 3 As shown, the evaluation device 10 includes an imaging unit 18 for acquiring a two-dimensional image of the stacked body 5, and an information processing device 19 connected to the imaging unit 18. The imaging unit 18 includes an image magnification unit 18a for magnifying the image of the stacked body 5, and an imaging unit body 18b that is close to or connected to the image magnification unit 18a.

[0043] As the image magnification unit 18a, a stereo microscope or magnifying glass can be used, for example. The image magnification is preferably about 2 to 50 times. Furthermore, the imaging unit body 18b can be, for example, a digital camera such as a CCD camera or a CMOS camera. The image magnification unit 18a and the imaging unit body 18b can be integrated and combined into one unit.

[0044] The imaging unit 18 can be arranged on one side of the laminate 5 (the upper side in the illustrated example). On the other side of the laminate 5, a light source (light projection unit) 17 that projects light L onto the laminate 5 can be arranged. With this arrangement, a transmission image can be captured. Here, in the case where the laminate 5 has two different layers, the image can be captured from one side of either layer. It should be noted that when capturing a transmission image in the case where the laminate 5 is composed of a base fabric and a polymer layer, from the viewpoint of being able to capture the outline of the air bag more clearly, it is preferable to capture from the polymer layer side. In addition, the arrangement of the imaging unit 18 and the light source 17 is not limited to the arrangement shown in the illustration; the light source 17 can also be arranged on the same side as the imaging unit 18, and a reflected image can be captured. In the case of capturing a reflected image, it is preferable to apply the light L from the light source 17 from an oblique direction, rather than applying it perpendicularly to the surface direction of the laminate 5.

[0045] As described above, the image acquired by the imaging unit 18 can be a reflected image or a transmitted image. Both reflected and transmitted images can be captured, and analysis can be performed based on both types of data. Alternatively, multiple images can be captured independently of reflected and transmitted images, and analysis can be performed based on these multiple images. Furthermore, although in Figure 3 In the example, the imaging unit 18 is arranged on a line orthogonal to the surface direction of the laminate 5 to obtain a planar view image. However, the image obtained by the imaging unit 18 is not limited to a planar view image; it can also be an image obtained by photographing the laminate 5 from an oblique direction. It should be noted that the light source 17 can be provided in the imaging unit 18, forming a device that integrates the two. Furthermore, the obtained image can be not only a top view of the laminate but also a cross-sectional image of the laminate, as described later.

[0046] The information processing device 19 acquires, analyzes, and evaluates image data of the laminate 5 captured by the imaging unit 18. The information processing device 19 can be an information processing device with computational processing and display functions, and can be a general-purpose personal computer. In the analysis performed by the information processing device 19, the region corresponding to the airbag can be detected in the two-dimensional image of the laminate 5, a characteristic value related to the area of ​​the detected airbag region can be obtained, and one or more characteristics of the laminate can be evaluated based on this characteristic value. Therefore, the quality of the laminate can ultimately be evaluated.

[0047] Figure 4 An example of the functional configuration of the evaluation apparatus 10 for implementing the evaluation method according to this embodiment is shown. For example... Figure 4 As shown, the evaluation device 10 is configured to include an input unit 11, an output unit 12, an image acquisition unit (image acquisition unit) 13, a storage unit 14, an analysis unit 15, and a control unit 16. The analysis unit 15 may include an air bag detection unit 15a, a characteristic value acquisition unit 15b, and an evaluation unit 15c.

[0048] The input unit 11 accepts various inputs, such as start / end and settings, from users or others, regarding image acquisition or image analysis. The input unit 11 may be an input interface such as a touch screen, keyboard, or mouse, or a voice input device such as a microphone.

[0049] The output unit 12 outputs content input from the input unit 11, or content executed based on the input content. The output unit 12 may be, for example, a display or a speaker.

[0050] The image acquisition unit 13 can acquire images or image information captured by the shooting unit 18. The image acquired by the image acquisition unit 13 can be a black and white image or a color image. A black and white image can be a grayscale image.

[0051] The storage unit 14 stores various data, including images acquired by the image acquisition unit 13 and analysis results obtained by the air bag detection unit 15a, characteristic value acquisition unit 15b, and evaluation unit 15c in the analysis unit 15. Furthermore, as described later, in the case of a manufacturing apparatus 100 that forms a laminate by connecting the evaluation device 10 and the bonding device 20, the storage unit 14 may also store data such as setting values ​​related to the bonding conditions of the bonding device 20, the material or thickness of the layers used, the intended use of the laminate, or values ​​related to the allowable level of bonding strength.

[0052] The air bag detection unit 15a is a unit that performs image processing on the two-dimensional image of the laminate 5 acquired by the image acquisition unit 13 and detects the region corresponding to the air bag. As described above, since the air bag existing between the two layers of the laminate is a part sealed with air or other gases, the refractive index of light in this part is different from the refractive index of the surrounding area, and the transmittance and reflectance of light are different. Therefore, the optical feature quantities of the region corresponding to the air bag in the obtained two-dimensional image are different from those of the surrounding area. Thus, by measuring the distribution of the optical feature quantities of the acquired two-dimensional image, the region corresponding to the air bag in the two-dimensional image can be easily extracted.

[0053] It should be noted that the area corresponding to the air bag can be the two-dimensional region occupied by the air bag (the part where the base fabric and polymer layer are not bonded) in the image, or it can be a region that exhibits different optical characteristics from the surrounding area due to the presence of the air bag. For example, it can be a region that includes the two-dimensional region occupied by the air bag and the surrounding area where the bonding strength is weakened due to the presence of the air bag, or it can be a region within the two-dimensional region occupied by the air bag where the optical characteristics are significantly different from the surrounding area.

[0054] The aforementioned optical features can be, for example, brightness values ​​and contrast values. Furthermore, when the acquired image is a color image, these can be features related to the color space, such as hue or saturation. From the viewpoint of being able to accurately detect the area occupied by the airbag and easily perform image processing, the optical features are preferably brightness values.

[0055] Figure 5 An image acquired by the image acquisition unit 13 is shown as an example. Figure 5 This is a planar view image obtained by photographing the laminate formed by bonding the base fabric and the polymer layer from the polymer layer side. Figure 5 The base fabric used in the layered structure shown is a base fabric made by plain weaving warp and weft yarns as multiple single fiber bundles. Air pockets are observed at the intersection of the warp and weft yarns.

[0056] Image processing performed by the airbag detection unit 15a can be performed directly on the acquired image, or the image can be converted into a predetermined format and processed on the converted image. For example, the acquired image can be converted into a grayscale image first.

[0057] In the airbag detection unit 15a, binarization can be performed on the acquired image or an image acquired and converted into a predetermined format based on a predetermined threshold. For example, in the case of acquiring an 8-bit, 256-level grayscale image (0-255), binarization processing can be performed by setting the threshold to 245, converting pixels with a brightness value below 254 to black (brightness value 0), and converting pixels with a brightness value of 255 to white (brightness value 255), thereby generating a binarized image. When using... Figure 3 In the case of the evaluation device 10 shown, the white area in the above-described binarized image can constitute the area corresponding to the air bag. It should be noted that the threshold is not limited to the value described above, and can be appropriately selected according to the thickness of the laminate being evaluated, the materials used, the shooting conditions, etc.

[0058] Alternatively, after the binarization process described above, the image can be inverted (black and white). This would display the area corresponding to the air sac as black and the other areas as white. Figure 6 This shows an image that has been binarized and then further inverted in black and white. Figure 6 In the example, the black area corresponds to the area of ​​the air bag.

[0059] It should be noted that Gaussian filtering, median filtering, or other smoothing and sharpening processes can be applied to the image before or after binarization. Alternatively, the airbag can be visually inspected while the outline is manually modified.

[0060] The characteristic value acquisition unit 15b is a unit that calculates characteristic values ​​as an indicator of adhesion strength based on the area corresponding to the airbag detected (extracted) by the airbag detection unit 15a. The characteristic value can be a characteristic value related to the area corresponding to the airbag. For example, the characteristic value could be the total area S of the area corresponding to the airbag. AP Relative to the total area S of the analyzed image T The ratio (%) (S) AP / S T ×100), sometimes this ratio is called porosity (%). In the above-mentioned black-and-white inverted binarized image ( Figure 6 In the diagram, the porosity is the total S of the black area. B The total S relative to the white area W Total S with the black area B The ratio of the sums (%) (S) B / (S W +S B (×100).

[0061] Characteristic values ​​related to the area of ​​the region corresponding to the air bag are not limited to porosity (%). They can be the total area, maximum value, average value, etc. of the area corresponding to the air bag, or values ​​obtained from the distribution of the area corresponding to the air bag, such as median, standard deviation, etc.

[0062] Evaluation unit 15c can evaluate the laminate based on characteristic values ​​related to the airbags obtained by unit 15b. More specifically, it can evaluate one or more characteristics of the laminate based on characteristic values ​​related to the area corresponding to the airbags. Furthermore, the quality of the laminate can be evaluated by evaluating one or more characteristics of the laminate.

[0063] As described above, there is a correlation between characteristic values ​​related to the area corresponding to the air bag and one or more characteristics of the laminate. Therefore, by pre-determining this correlation using multiple existing laminates, one or more characteristics of the laminate being evaluated can be assessed. For example, multiple laminates can be prototyped by changing the bonding process conditions without changing the material, thickness, etc., of the two layers used as the laminate material. Then, for each prototype laminate, characteristic values ​​(porosity, etc.) are determined as described above, and predetermined characteristics of each prototype laminate are calculated, and the correlation between the two is determined (by plotting a calibration curve). If this correlation is determined, the predetermined characteristics can be qualitatively or quantitatively evaluated by analyzing a two-dimensional image of the laminate to be evaluated.

[0064] When evaluating the bonding strength of laminates, the peel force can be measured using conventional methods during the stage of establishing the aforementioned correlation, and this measurement can be used as the bonding strength of a prototype laminate including the predetermined two layers. The correlation between the characteristic value of the area corresponding to the air bag and the peel force can be pre-determined, and the bonding strength (peel force) can be estimated based on this correlation. Therefore, it is unnecessary to measure the peel force generated by tearing for laminates with unknown bonding strength, and the process can be completed without damaging the laminate.

[0065] Generally, in laminates composed of two layers, lower peel strength results in lower compressive strength. Therefore, the compressive strength of the laminate can be measured and used to evaluate the bond strength. Compressive strength can be determined, for example, by fixing a predetermined area of ​​the laminate to a measuring fixture, applying pressure from the base fabric side of the laminate using a medium such as air or water, gradually increasing the pressure, and measuring the pressure at which the laminate breaks (pressure at break or pressure at failure (kPa)).

[0066] Furthermore, regarding pressure resistance, for example, internal pressure retention rate can be measured. Regarding internal pressure retention rate, for example, the laminate is arranged on a metal tube such that it covers the end of the tube, and the laminate is fixed in a way that the tube and the laminate are tightly connected using a cap with an attached flange, etc. Gas is filled into the tube, and gas filling is stopped at the point when the internal pressure reaches its maximum. After measuring the maximum internal pressure, the internal pressure can be measured over time, and the decay rate, etc., can be calculated. The correlation between this decay rate and a characteristic value related to the area of ​​the corresponding region of the air bag in the obtained two-dimensional image can be determined, and this value can be used to evaluate the laminate.

[0067] Furthermore, when the laminate used for airbags or the like becomes a bag-shaped structure as described later, the internal pressure retention characteristics of the bag-shaped laminate can be measured. For example, the internal pressure of the bag-shaped laminate is preset to a predetermined initial internal pressure P0, a gas pump or the like is connected to the gas inlet to allow gas to flow in from the gas inlet, and the internal pressure P of the bag-shaped laminate is measured using a pressure sensor installed near the gas inlet. i The internal pressure P of the bag-shaped laminate after a predetermined time can be measured. i The percentage relative to the initial internal pressure P0 is used as the internal pressure retention rate (P). i / P0×100). The correlation between the internal pressure retention rate and the characteristic value related to the area of ​​the corresponding region of the air bag obtained as described above can be determined and used for the evaluation of the laminate. Since the characteristics suitable for actual use can be determined by measuring the internal pressure retention rate in the above manner, a more practical evaluation of the bag-shaped laminate can be performed.

[0068] The correlation between the aforementioned characteristic values ​​and the characteristics of the laminate can be represented by a graph or equation (model). The graph or formula representing the correlation can be pre-stored in storage unit 14. The formula representing the correlation can be obtained by performing a regression analysis with the characteristic value related to the area corresponding to the air bag as the independent variable and the characteristic of the laminate as the dependent variable. In this case, multiple characteristic values ​​can be used as independent variables, or the characteristic value and other physical properties of the laminate (physical properties of the materials constituting the laminate, etc.) can be used as independent variables. As described later, when the characteristic value related to the area corresponding to the air bag is porosity, and the characteristic of the laminate is the pressure resistance of the laminate (pressure at break, internal pressure retention rate, etc.), if porosity is set as X and pressure resistance as Y, the following relationship holds.

[0069] Y = logX + b

[0070] However, the regression equations representing the correlation between characteristic values ​​and the properties of laminates are not limited to the formulas mentioned above. Linear regression equations or power regression equations can be used depending on the layer composition of the laminate, the type or size of the layer-forming materials, etc. Furthermore, when measuring two or more properties of a laminate, for example, determining both the fracture pressure and the internal pressure retention rate, multiple regression analysis can be performed using these two or more properties as independent variables to determine and evaluate the correlation with the overall properties.

[0071] It should be noted that, for example, image processing software such as ImageJ can be used for at least a portion of the processing performed by the air bag detection unit 15a, unit 15b and evaluation unit 15c described above.

[0072] The control unit 16 controls each of the units 11 to 15 constituting the evaluation device 10. Furthermore, as described later, in the case of a manufacturing apparatus 100 that connects the evaluation device 10 and the bonding device 20 to form a laminate, the control unit 16 can also perform feedback control of the bonding device 20.

[0073] Each of the above units 11 to 16 can be generated as a program that can be executed by a computer, and the evaluation device 10 according to this embodiment can be realized by installing it in a general personal computer, server, etc.

[0074] One embodiment of the present invention is a method for manufacturing a laminate, which is formed by laminating two or more layers. The manufacturing method includes: laminating two or more layers to form a laminate, and evaluating the laminate online using the method described above for evaluating the laminate.

[0075] Another embodiment of the present invention is an apparatus for manufacturing a laminate formed by bonding two or more layers. The apparatus includes: a bonding unit for bonding at least one layer made of a polymer and two or more layers to form a laminate; and the aforementioned apparatus for evaluating the laminate, subsequently disposed within the bonding unit.

[0076] Refer again Figure 1 The manufacturing method of the laminate and the manufacturing apparatus 100 for the laminate will be described. Figure 1 An example is shown of a laminate 5 made by bonding a base fabric 4 and a polymer layer 1. Figure 1As shown, the laminate manufacturing apparatus 100 includes a laminate bonding device (laminator) 20 and an evaluation device 10 for the laminate subsequently placed in the bonding device 20. The laminate 5 is typically conveyed by a transport unit such as a belt conveyor and ultimately wound onto rollers or the like. The evaluation device 10 can evaluate the bonding strength of the laminate 5 during the transport period before winding, i.e., evaluate the bonding strength of the laminate 5 in an online manner.

[0077] The evaluation device 10 includes an imaging unit 18, which is capable of capturing two-dimensional images of the stacked body 5 during transport. The data from the images captured by the imaging unit 18 is sent to the information processing device 19 and analyzed as described above.

[0078] As described above, there is a correlation between the air bag region and one or more properties (e.g., bonding strength) of the laminate. Therefore, if this correlation is determined in advance for a laminate using a predetermined base fabric and a predetermined polymer layer, the predetermined properties can be estimated by obtaining an image of the laminate whose predetermined properties are unknown. Thus, if images of the laminate located on the production line can be captured, the laminate during manufacturing can be evaluated. Furthermore, by feeding back this evaluation result, the bonding conditions between the base fabric and the polymer layer, such as heating and / or pressurization conditions, can be modified to manufacture a laminate optimal for its intended use.

[0079] For example, the allowable level of bonding strength can be preset and stored according to the intended use, and the evaluation results obtained by the evaluation unit 15c can be used to determine whether the allowable level has been reached. If the bonding strength of the laminate during manufacturing does not reach the allowable level, a signal is sent to the control unit 16 to change the driving conditions of the heating unit 22 and / or the pressurizing unit 23, so as to change the conditions.

[0080] exist Figure 1 In the example shown, the evaluation device 10 is included in the laminate manufacturing apparatus 100. However, the evaluation device 10 may also be configured as a separate device, i.e., a stand-alone device, rather than being included in the laminate manufacturing apparatus 100.

[0081] When using this stand-alone evaluation device, the laminate can be evaluated offline, not on the production line, but in a state away from the production line. This type of offline evaluation can be performed, for example, by cutting an evaluation sample (a slice of the laminate) from the laminate immediately after manufacturing and analyzing that sample. Alternatively, when evaluating using a planar view image of the laminate, a portion of the laminate can be analyzed without cutting a sample. The analysis performed using this type of stand-alone evaluation device allows for the evaluation of the laminate immediately after manufacturing or the evaluation of the manufacturing method (evaluation of whether the manufacturing conditions, etc., are suitable). Compared with the evaluation device assembled into the laminate manufacturing apparatus 100 (… Figure 1 Similarly, the analysis results from the evaluation can be stored in the evaluation device 10, specifically in the storage unit 14. Users of the manufacturing apparatus can modify the conditions of the manufacturing apparatus during the manufacturing of the laminate or at the next operation of the manufacturing apparatus, based on the stored analysis or evaluation results.

[0082] Furthermore, when using a stand-alone evaluation device, evaluation can be performed not only on laminates immediately after manufacturing but also on laminates that have been stored or placed under predetermined conditions for a predetermined period of time since manufacturing. To evaluate such laminates, an evaluation sample can be cut from the laminate and analyzed, or the laminate can be analyzed intact without cutting off the sample. In either case, the quality changes of the laminate over time can be evaluated by comparing the analytical results obtained from analyzing a laminate that has been stored for a certain period of time with the analytical results obtained from analyzing a laminate immediately after manufacturing.

[0083] Furthermore, a stand-alone evaluation device can be used to evaluate part or all of the process used to manufacture products (such as airbags) from laminates, for example, evaluating the laminate after a process such as cutting has been performed. In this case, the laminate contained in the manufactured product can be evaluated, or the laminate contained in the used product can be evaluated. When evaluating the laminate contained in the used product, the quality changes of the laminate due to use can be evaluated by comparing the analysis results obtained from analyzing the laminate before use with the analysis results obtained from analyzing the laminate used under predetermined time and conditions.

[0084] When evaluating quality changes caused by the passage of time or by use, the evaluation results can help improve storage and usage methods.

[0085] Even when the evaluation device is configured as a standalone device, its specific configuration can still be as described above. Figures 1-4 The basic structure is the same. However, since the independent evaluation device is not assembled into the manufacturing device 100 ( Figure 1 Due to limitations within the scope of evaluation, the more specific configuration of the evaluation device and the composition of the evaluation method can include further diversity.

[0086] For example, through the imaging unit 18 in the evaluation device 10 ( Figure 3 and Figure 4 The obtained two-dimensional image of the laminate can be either a plan view or a cross-sectional image. That is, the laminate can be cut along its thickness direction, and its cross-section can be photographed. By using the cross-sectional image for evaluation, especially when the laminate is configured into a bag shape for use in airbags, etc., it is possible to appropriately and selectively evaluate the structural portions (also called the main body) and / or the seams (also called the ends), particularly the seams, of the bag-shaped laminate. When photographing cross-sectional images, Figure 3 The laminate 5 in the original text is replaced with a sample sheet obtained by thinly cutting the laminate along its thickness direction. It should be noted that the cross-sectional images used can be images taken in a direction orthogonal to the cross-section, or images obtained by taking images of the cross-section in an oblique direction.

[0087] The image magnification unit 18a (such as a microscope) and the main body 18b (of the imaging unit) can be used. Figure 3 The sample slides of the laminate used to prepare cross-sectional images are photographed. There are no particular limitations on the cutting method of the laminate, but a microtome or ultramicrotome is preferred. Thin sections can be prepared by cutting the sample slides. Furthermore, there are no particular limitations on the pretreatment method accompanying the cutting using a microtome, i.e., the sample fixation method; methods such as freezing or embedding with epoxy resin are also acceptable.

[0088] It should be noted that when obtaining sheet-like samples, if the laminate contains a fabric base, the direction of the cutting line that cuts the laminate in the thickness direction can be along any direction of the warp and weft yarns constituting the fabric, or it can be the direction that intersects the two yarns.

[0089] Similarly, the airbag detection unit 15a can be used, as described above, to detect the airbag image. Figure 4 The acquired cross-sectional image is processed. Specifically, the cross-sectional image is converted into a predetermined format and then binarized, or the acquired cross-sectional image is directly binarized. This allows for the detection of the region corresponding to the airbag to be observed in the cross-section.

[0090] There are no particular limitations on the light projection method used when taking cross-sectional images with a microscope. The implementation method described is different from that used for obtaining planar view images. Figure 3 Similarly, the light source (light projection unit) 17 can be arranged from the underside of the sample sheet of the laminate, that is, on the side opposite to the imaging unit 18, or on the same side as the imaging unit 18. In addition, during imaging, bright-field method, dark-field method, etc. can be used.

[0091] Figure 10 An example of a cross-sectional image that can be acquired by the imaging unit 18 is shown. Figure 10 This is a cross-sectional image of the laminate obtained in Example 4-1 described later. This cross-sectional image was obtained by photographing the thin section using a microscope (image magnification unit) (by comparing with...). Figure 2 (The image is obtained by cutting in the same way). The slice is cut from the laminate at a cutting line along one fiber direction using a cryostat. The laminate is formed by bonding polymer layers to both sides of a plain-weave fabric base. It should be noted that... Figure 10 The image was obtained through observation and photography using the dark-field method. According to... Figure 10 It can be seen that the air bag appears black between the base fabric and the polymer layer, especially at the intersection of the warp and weft yarns.

[0092] Figure 11 The figure shows a pair with a predetermined threshold as a reference. Figure 10 An example of a cross-sectional image that has been binarized and whose black and white values ​​have been inverted. Figure 11 In the binarized image shown, in Figure 10 The area corresponding to the black airbag in the middle is displayed as white, and its optical characteristics are different from other areas.

[0093] Even when using a profile image as in this example, it is possible to obtain the data from a binarized image ( Figure 10 The bonding strength index is obtained from the data. Specifically, similar to the case using a planar view image, the characteristic values ​​of unit 15b can be used to obtain the bonding strength index. Figure 4 The porosity and other characteristic values ​​related to the area of ​​the corresponding region of the air bag are calculated. Furthermore, similar to the case using a planar view image, the bonding strength of the laminate can be evaluated by pre-calculating the correlation between the calculated characteristic values ​​and the bonding strength.

[0094] It should be noted that the laminate can be evaluated by combining characteristic values ​​related to the area corresponding to the airbag obtained from the planar view image and characteristic values ​​related to the area corresponding to the airbag obtained from the cross-sectional image. That is, predetermined characteristic values ​​obtained from the planar view image and predetermined characteristic values ​​obtained from the cross-sectional image can be used as benchmarks to evaluate whether the benchmark based on the two characteristic values ​​is met. For example, if the porosity obtained from both the planar view image and the cross-sectional image is less than a predetermined value, it can be judged as having good quality. Regarding the predetermined value of the porosity used as the judgment benchmark, for example, it can be set by pre-calculating a porosity threshold for obtaining the desired fracture pressure based on the porosity obtained from the planar view image, and pre-calculating a porosity threshold for obtaining the desired internal pressure retention rate based on the porosity obtained from the cross-sectional image. Furthermore, when the laminate is configured as a bag, for example, when a single-piece fabric is used as the base fabric, a plan view image can be obtained from the main body of the base fabric, and a cross-sectional image can be obtained from the seam portion of the base fabric (described later), and the porosity can be calculated based on each image. Based on these two criteria, the laminate can be evaluated more accurately.

[0095] Therefore, this embodiment provides a method for evaluating a laminated body formed by bonding two or more layers. The method includes: an image acquisition step, acquiring a planar view image and a cross-sectional image of the laminated body; a detection step, detecting the corresponding area of ​​the air bag from the planar view image and the cross-sectional image respectively; a characteristic value acquisition step, calculating characteristic values ​​related to the area of ​​the corresponding area of ​​the air bag from the planar view image and the cross-sectional image respectively; and an evaluation step, evaluating the laminated body based on the aforementioned characteristic values.

[0096] In this embodiment, the laminate evaluated is sheet-like. This embodiment includes not only planar forms but also forms such as cylindrical, bag-like, and balloon-like shapes. Therefore, by... Figure 1 The laminating device 20 shown can laminate and transport multiple laminates in an overlapping state. Even in this case, if images are acquired and processed under the same conditions, the correlation between the presence of the air pocket corresponding area of ​​the laminate and the predetermined characteristics (e.g., bonding strength) of the laminate can be determined as described above.

[0097] Furthermore, by using the aforementioned evaluation method for laminates, it is also possible to effectively evaluate laminates that have an additional layer further disposed on top of a two-layer laminate. For example, it is possible to evaluate the overall strength of a three-layer laminate with polymer layers adhered to both sides of a base fabric.

[0098] When one of the two layers constituting the laminate is a base fabric, from the viewpoint of higher mechanical strength, the base fabric is preferably a woven fabric. In the case of a woven fabric, it can be a biaxial structure combining multiple warp and weft yarns, or a triaxial structure combining multiple warp, weft, and twill yarns. Furthermore, when the woven fabric is a biaxial structure, the weave can be plain weave, twill weave, satin weave, etc., but from the viewpoint of strength and ease of manufacturing, plain weave is preferred. Additionally, the base fabric also includes a one-piece woven fabric (OPW), which is not a flat base fabric, but rather seamlessly woven into a bag shape in a manner that allows it to have a curved surface according to the three-dimensional shape of the intended product.

[0099] It should be noted that when the laminate is bag-shaped for applications such as airbags, from the viewpoint of obtaining products with high airtightness, the base fabric included in the laminate is preferably a single-piece fabric. When using a bag-shaped base fabric as a single-piece fabric, the base fabric is manufactured, and polymer layers are arranged on both sides of the bag-shaped base fabric. That is, with the gas inside the bag removed and the main body of the base fabric having two overlapping layers, polymer layers are arranged on both sides. Then, at the edge of the base fabric, the polymer layers arranged on both sides are joined. In this case, a seam (end) can be formed at the edge of the base fabric. The seam is a portion where the weaving method of the base fabric is changed relative to the main body of the base fabric (the portion forming the bag body), and it exists as a single layer. Thus, the laminate including the single-piece fabric base fabric can have a main body portion and a seam portion when the gas inside the bag is removed. The main body portion is the portion where polymer layers are glued to both sides of the portion where two unjoined layers of base fabric overlap, and the seam portion is the portion where polymer layers are glued to both sides of the single-layer base fabric. In laminates according to this structure, although it is sometimes difficult to obtain a planar view image of sufficient area near the edge portion of the base fabric, especially at the seams, it is easy to obtain cross-sectional images within a sufficient range. Therefore, in the case of obtaining a two-dimensional image of the laminate, by obtaining a cross-sectional image and evaluating the laminate based on the characteristic values ​​obtained from the obtained image, it is possible to effectively evaluate the bonding strength between the layers of the laminate near the edge portion of the base fabric, especially at the seams.

[0100] There are no particular limitations on the type of fibers contained in the base fabric; they can be synthetic fibers, natural fibers, regenerated fibers, semi-synthetic fibers, inorganic fibers, and combinations thereof (including blends and weaves). Synthetic fibers, especially polymer fibers, are preferred. Core-sheath type fibers, parallel type fibers, split type fibers, and other composite fibers can also be used. When the fiber is a polymer fiber, examples of polymers include polyester fibers, polyamide fibers, aramid fibers, rayon fibers, ultra-high molecular weight polyethylene fibers, sulfone fibers, and polyetherketone fibers.

[0101] When the base fabric is a woven fabric, it can contain two or more types of fibers. For example, fibers with different materials, fineness, or cross-sectional shapes can be used as yarns extending in different directions. For instance, in the case of a biaxial structure including warp and weft yarns, the warp and weft yarns can be made of fibers of different kinds of materials. In this case, at least one of the warp and weft yarns can be polyester fiber.

[0102] The base fabric can be formed using yarns with a total fineness (single yarn fineness × number of blended yarns) of 100 to 700 dtex. Furthermore, the single yarn fineness of the fibers used in the base fabric is preferably 1 to 10 dtex. When the base fabric is a plain weave fabric, the weave density is preferably 5 to 30 yarns / cm for both warp and weft. 2 Basis weight of the base fabric (per 1m) 2 The weight can be approximately 30–300 g / m³. 2 .

[0103] When one of the two layers constituting the laminate is a flexible polymer layer, the polymer used for the polymer layer can be a resin, rubber, or an elastomer, etc. From the viewpoint of being able to be bonded to a base fabric by thermal fusion, a thermoplastic material is preferred. The polymer layer can be a single layer or composed of two or more layers. When the polymer layer is composed of two or more layers, the material and thickness of the two or more layers can be the same or different from each other. Furthermore, in the case of a configuration in which two or more flexible polymer layers are bonded to a base fabric, the layer bonded to one side of the base fabric is preferably a layer made of a thermoplastic material.

[0104] Examples of resins include polyester resins, polyamide resins, polyolefin resins, polystyrene resins, and ethylene-vinyl acetate copolymers. These resins can be modified using acids or the like, depending on their layer structure or intended use.

[0105] Examples of polyolefin resins include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene. The polyolefins used can be modified with unsaturated carboxylic acids such as acrylic acid, maleic acid, and fumaric acid, or their anhydrides and derivatives.

[0106] As an elastomer, one or more of the following can be cited: polyester elastomers, polyamide elastomers, polyolefin elastomers, polyurethane elastomers, polystyrene elastomers, and polybutadiene elastomers.

[0107] As a thermoplastic material, thermoplastic polyester elastomers are preferred. In the case of thermoplastic polyester elastomers, the hard segments include polybutylene terephthalate, polyethylene terephthalate, or polypropylene terephthalate, including polybutylene terephthalate, while the soft segments preferably include aliphatic polyethers and / or aliphatic polyesters. Furthermore, thermoplastic polyester elastomers can be modified in the presence of a free radical generator using unsaturated carboxylic acids such as acrylic acid, maleic acid, and fumaric acid, or their anhydrides and derivatives.

[0108] The melting point of the polymers constituting the polymer layers can range from approximately 70 to 250°C. It should be noted that the melting point of a polymer refers to the temperature at which the layer softens when the temperature is raised, the polymer molecules within the layer begin to move relative to each other, and the polymer exhibits fluidity. The melting point of a polymer can be determined using differential scanning calorimetry (DSC).

[0109] It should be noted that, in the case of multiple polymer layers, it is preferable that at least the polymer layer attached to the base fabric is made of a material exhibiting a melting point, which is preferably within the range described above.

[0110] It should be noted that other components besides the polymer can be added to the polymer layer. Examples of such other components include pigments, fillers, antioxidants, anti-sticking agents, hydrolysis inhibitors, and other additives.

[0111] [Example]

[0112] The present invention will be described in more detail below through embodiments, but the present invention is not limited to these embodiments.

[0113] [I. Example of using a plan view image]

[0114] In the following embodiments, multiple laminates were fabricated using the same base fabric and the same polymer layer, with variations in bonding temperature and bonding speed (transfer speed). The porosity (ratio of air pockets) of each laminate was then measured from plan view images, and the compressive strength (pressure at break) of each laminate was also measured. The correlation between porosity and compressive strength was determined for each laminate.

[0115] (Example 1-1)

[0116] Prepare base fabric CL1 (made of polyester, with a total fineness of 470 dtex for both warp and weft yarns, and a basis weight of 200 g / m²). 2 Additionally, prepare film F1 (a multilayer film formed by stacking a polymer layer with a melting point of 170°C and a polymer layer with a melting point of 125°C). Then, use it with reference... Figure 1 The same apparatus used in the fabrication apparatus 100 described above is used to bond the base fabric CL1 and the film F1 together by heating and pressurizing, with the layer of film F1 having the lower melting point located on the side of the base fabric CL1, to produce a laminate. At this time, a total of four laminates were produced by varying the heating temperature to 150°C and the bonding speed between 3 and 10 m / min.

[0117] The fabricated stack was mapped in planar view at 30x magnification using a stereo microscope (Nikon SMZ1500), and images were captured using a camera. Images were acquired using a camera control unit (Nikon Digital Sight DS-L3, 2560×1920 pixels). The acquired images were converted into 8-bit, 256-grayscale images using image processing software (ImageJ). Furthermore, after black-and-white inversion, the images were converted into binarized images with a brightness value of 254 as the threshold (brightness values ​​below 254 were set to black (brightness value 0), and brightness values ​​below 255 were set to white).

[0118] In the above image after binarization, the ratio of the area of ​​the black region to the area of ​​the entire image is calculated, that is, the total area S of the black region. B / (Total area of ​​black region S) B + Total area of ​​the white region S W )×100, and use this value as the presence ratio of the air bag, i.e., the porosity (%).

[0119] On the other hand, for each of the four laminates, the pressure at fracture (kPa) was used as the compressive strength and was measured. The compressive strength was measured as follows: The laminates were cut into 20cm squares and fixed on a Textest FX3000 4H sample holder. Then, the pressure was increased at a rate of 120kPa / min, and the pressure at which the laminates broke was measured.

[0120] Plot the porosity and pressure resistance of each laminate in a semi-logarithmic chart. Figure 7 It should be noted that, in Figure 7 In the chart, although a dashed line is drawn at the location of the compressive strength of 250 kPa, this compressive strength can be considered an acceptable level of bonding strength of the laminate. Therefore, in the process of... Figure 1 When the manufacturing apparatus 100 shown is used to manufacture the laminate, it is possible to... Figure 7 The permissible levels shown in the chart serve as a benchmark for controlling heating, pressurization, and other processes.

[0121] (Examples 1-2)

[0122] Except that film F2 (a multilayer film formed by laminating polymer layers with a melting point of 209°C and polymer layers with a melting point of 149°C) was used instead of film F1, the base fabric CL1 and film F2 were laminated to create a laminate, similar to Example 1-1. In this case, the lamination temperature was varied between 170 and 180°C, and the lamination speed was varied between 3 and 10 m / min, resulting in a total of three laminates. Furthermore, similar to Example 1-1, the porosity and compressive strength (pressure at break) were determined for each laminate and plotted in a semi-logarithmic graph. Figure 7 ).

[0123] (Examples 1-3)

[0124] Except that film F1 was replaced with film F3 (a multilayer film formed by stacking layers with a melting point of 209°C, a melting point of 150°C, and a melting point of 109°C in that order, each layer being a polymer layer), the laminates were fabricated in the same manner as in Example 1-1. In this case, film F3 was bonded to the base fabric CL1 with the layer of film F3 having the lowest melting point on the base fabric CL1 side. Furthermore, the bonding temperature was varied between 170 and 180°C, and the bonding speed was varied between 3 and 10 m / min, resulting in a total of four laminates. In addition, as in Example 1-1, the porosity and compressive strength (pressure at break) of each laminate were determined and plotted in a semi-logarithmic graph. Figure 7 ).

[0125] (Example 2-1)

[0126] Prepare the base fabric CL2 (polyester, with a total fineness of 470 dtex for both warp and weft yarns, and a basis weight of 220 g / m²). 2 Additionally, prepare the aforementioned film F1. Similar to Example 1-1, the base fabric CL2 and film F1 are bonded together by heating and pressurization to create a laminate. At this time, the bonding temperature is set to 170°C, and the bonding speed is varied between 3 and 10 m / min, thereby creating a total of four laminates. Furthermore, similar to Example 1-1, the porosity and compressive strength (pressure at break) of each laminate are calculated and plotted in a semi-logarithmic graph. Figure 8 ).

[0127] (Example 2-2)

[0128] Except that film F1 was replaced with film F4 (a multilayer film formed by stacking polymer layers with a melting point of 187°C and polymer layers with a melting point of 144°C), a total of four laminates were fabricated in the same manner as in Example 2-1. Furthermore, as in Example 2-1, the porosity and compressive strength (pressure at fracture) of each laminate were determined and plotted in a semi-logarithmic graph. Figure 8 ).

[0129] (Example 3-1)

[0130] Prepare the base fabric CL3 (polyester, with a total fineness of 470 dtex for both warp and weft yarns, and a basis weight of 210 g / m²). 2 Additionally, prepare the aforementioned film F2. Similar to Example 1-1, the base fabric CL3 and film F2 are bonded together by heating and pressurization to create a laminate. At this time, the bonding temperature is set to 170°C, and the bonding speed is varied between 3 and 10 m / min, thereby creating a total of four laminates. Furthermore, similar to Example 1-1, the porosity and compressive strength (pressure at break) of each laminate are calculated and plotted in a semi-logarithmic graph. Figure 9 ).

[0131] (Example 3-2)

[0132] Except that film F3 was used instead of film F2 as described above, a total of four laminates were fabricated in the same manner as in Example 3-1. Furthermore, as in Example 3-1, the porosity and compressive strength (pressure at fracture) of each laminate were determined and plotted in a semi-logarithmic graph. Figure 9 ).

[0133] Depend on Figures 7-9It can be seen that a good correlation was found between porosity and compressive strength (bonding strength) for laminates using a predetermined base fabric and a predetermined polymer layer. Based on this correlation, the bonding strength of the laminate can be accurately and easily evaluated.

[0134] [II. Examples of using cross-sectional images]

[0135] Laminates were fabricated using the same base fabric and the same polymer layer, with variations in the lamination speed. The porosity (the ratio of air pockets) was then measured from cross-sectional images of each laminate, and the internal pressure retention rate, a measure of the pressure resistance of each laminate, was determined.

[0136] (Example 4-1)

[0137] Prepare a base fabric CL1 (in this example, a single-piece fabric woven into a bag-shaped airbag) and a film F3. Unfold the base fabric CL1 into a flat shape (with two layers of the bag-shaped base fabric overlapping), and arrange the film F3 on both sides of the base fabric CL1 such that the layer with the lower melting point among the multiple layers of film F3 is located on the side of the base fabric CL1. Then, by utilizing... Figure 1 The laminating device 20 heats and pressurizes the laminator to create a laminate (a laminate formed by laminating the film F3 onto the outer surface of the bag-shaped base fabric CL1) sandwiching the base fabric CL1 between two films F3. The lamination temperature is 175°C, and the lamination speed is 2.4 m / min. It should be noted that the edge of the laminate does not include the base fabric CL1, but includes the portion where the films F3 are directly bonded to each other.

[0138] On the other hand, a cross-sectional image of the seam (end) of the base fabric CL1 was obtained. That is, a cross-sectional image was obtained at the edge of the base fabric CL1 from the portion of the film F3 protruding from both sides of the base fabric monolayer. More specifically, a thin section cut along the thickness direction of the laminate was prepared using a cryostat. The thin section was mapped and photographed using a Nikon LV-100 at a magnification of 150x.

[0139] Images were acquired using a camera control unit (Nikon Digital Sight DS-L3, 2560×1920 pixels). Image processing software (ImageJ) was used to convert the acquired images into 8-bit, 256-grayscale images. Furthermore, after black-and-white inversion, the images were converted into binarized images with a brightness value of 254 as the threshold (brightness values ​​below 254 were set to black (brightness value 0), and brightness values ​​of 255 were set to white).

[0140] In the above image after binarization, the ratio of the area of ​​the black region to the area of ​​the entire image is calculated, that is, the total area S of the black region.B / (Total area of ​​black region S) B + Total area of ​​the white region S W )×100, and use this value as the presence ratio of the air bag, i.e., the porosity (%). Figure 10 and Figure 11 The cross-sectional image of Example 4-1 and the image after binarization are shown respectively.

[0141] On the other hand, the internal pressure retention rate of the laminate was determined. Specifically, a compressed gas generator was connected to the gas (air) inlet of the bag-shaped laminate, gas was introduced, and the initial internal pressure was set to 70 kPa. Then, the air supply was stopped, and the internal pressure of the laminate was measured using a pressure sensor installed near the gas inlet. The percentage of the internal pressure after 6 seconds relative to the initial internal pressure was then calculated and used as the internal pressure retention rate (%). The results are shown in Table 1.

[0142] (Example 4-2)

[0143] Similar to Example 4-1, a bag-shaped laminate made of base fabric CL1 and film F3 was fabricated, but the bonding speed was 1.6 mm / min. Then, similar to Example 4-1, a cross-sectional image of the seam was obtained, and a binarized image was further obtained from the obtained image. Figure 12 and Figure 13 The cross-sectional image of Example 4-1 and the image after binarization are shown respectively.

[0144] Similar to Example 4-1, the porosity was determined and the internal pressure retention rate was measured. The results are shown in Table 1.

[0145] [Table 1]

[0146] Example 4-1 Example 4-2 porosity 20％ 7％ Internal pressure after 6 seconds <40kPa 47.9 kPa Internal pressure retention rate <57％ 68％

[0147] As can be seen from Table 1, the internal pressure retention rate of the laminate of Example 4-2, which has a smaller porosity, is greater than that of the laminate of Example 4-1, which has a larger porosity. Therefore, by using the evaluation apparatus and method according to this embodiment, and by taking a cross-sectional image of the laminate and determining the porosity, it is possible to estimate the trend of the internal pressure retention rate of the laminate, and further estimate and evaluate the trend of the internal pressure retention characteristics or bonding strength.

[0148] This application claims priority based on Japanese Patent Application No. 2019-132201, filed with the Japanese Patent Office on July 17, 2019, the entire contents of which are incorporated herein by reference.

[0149] Symbol Explanation

[0150] 1. First layer (polymer layer);

[0151] 4. Second layer (base fabric);

[0152] 5-layered structure;

[0153] 10. Evaluation device;

[0154] 11. Input Unit;

[0155] 12 Output Units;

[0156] 13 Image acquisition unit;

[0157] 14 storage units;

[0158] 15 Analysis Units;

[0159] 15a Airbag Detection Unit;

[0160] 15b Characteristic value acquisition unit;

[0161] 15c Evaluation Unit;

[0162] 16. Control unit;

[0163] 17. Light source;

[0164] 18 shooting units;

[0165] 18a Image magnification unit;

[0166] 18b Main shooting unit;

[0167] 19. Information processing device;

[0168] 20. Laminating equipment (laminator);

[0169] 22. Heating section;

[0170] 23. Pressurization section;

[0171] 24. Cooling section;

[0172] A manufacturing apparatus for 100-layer stacks.

Claims

1. A method for evaluating a laminate, the laminate being formed by bonding two or more layers, one of which is a base fabric and the other is a flexible polymer layer bonded to the base fabric, the laminate being bag-shaped, the base fabric being a single-piece fabric, two base fabrics being joined together at their respective sides to form a bag, the flexible polymer layer being disposed on the outer surface of the bag, the bag including a body and a seam, the body being a portion forming a space with the two base fabrics, and the seam being a portion where the two base fabrics are joined together, the method comprising: The image acquisition step involves acquiring a two-dimensional image of the laminate, the two-dimensional image including a cross-sectional image along the thickness direction of the laminate and a planar image of the laminate, the cross-sectional image being obtained from the seam and the planar image being obtained from the body; The detection step involves detecting the region corresponding to the air bag from the cross-sectional image and the planar image, wherein the region corresponding to the air bag is between the base fabric and the flexible polymer layer; The characteristic value acquisition step involves obtaining a first characteristic value associated with the area of ​​the region corresponding to the air bag from the cross-sectional image and obtaining a second characteristic value associated with the area of ​​the region corresponding to the air bag from the planar image. as well as The evaluation step involves evaluating the laminate based on the first characteristic value and the second characteristic value.

2. The method according to claim 1, wherein, The evaluation step includes evaluating the correlation between the first characteristic value and the second characteristic value and the compressive strength of the laminate.

3. The method according to claim 1, wherein, The detection step includes detecting the region corresponding to the air bag based on the optical features of the cross-sectional image and the planar image.

4. The method according to claim 3, wherein, The optical characteristic quantity is the brightness value.

5. The method according to claim 1, wherein, The detection steps include binarization processing.

6. An apparatus for evaluating a laminate formed by bonding two or more layers, one of which is a base fabric and the other is a flexible polymer layer bonded to the base fabric, the laminate being bag-shaped, the base fabric being a single-piece fabric, two base fabrics being joined together at their respective sides to form a bag, the flexible polymer layer being disposed on the outer surface of the bag, the bag including a body and a seam, the body being a portion forming a space with the two base fabrics, and the seam being a portion where the two base fabrics are joined together, the apparatus comprising: The image acquisition unit acquires a two-dimensional image of the laminate, the two-dimensional image including a cross-sectional image along the thickness direction of the laminate and a planar image of the laminate, the cross-sectional image being obtained from the seam and the planar image being obtained from the body; The detection unit detects the corresponding area of ​​the air bag from the cross-sectional image and the planar image, the corresponding area of ​​the air bag being between the base fabric and the flexible polymer layer; The characteristic value acquisition unit calculates a first characteristic value related to the area of ​​the region corresponding to the air bag from the cross-sectional image and a second characteristic value related to the area of ​​the region corresponding to the air bag from the planar image; as well as The evaluation unit evaluates the laminate based on the first characteristic value and the second characteristic value.

7. A method for manufacturing a laminated body, the laminated body being formed by bonding two or more layers together. Two or more layers are laminated to form a laminate, wherein one of the two or more layers is a base fabric and the other is a flexible polymer layer laminated to the base fabric; and The laminate is evaluated online using the method according to claim 1.

8. The method according to claim 7, wherein, The results of the evaluation are fed back to adjust the fitting conditions.

9. An apparatus for manufacturing a laminated body formed by bonding two or more layers, the apparatus comprising: A bonding unit that bonds two or more layers to form a laminate, wherein one of the two or more layers is a base fabric and the other is a flexible polymer layer bonded to the base fabric; and The device according to claim 6 is subsequently placed in the bonding unit.

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