JP2015152412A - defect identification method and defect identification system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a defect identification method and a defect identification system, capable of surely identifying a defective part of a coating film with high accuracy even if concentration of a fluorescent agent in coating liquid is reduced, at low cost.SOLUTION: While transporting a web W having a coating film CF containing a fluorescent agent, in a defect identification method for identifying a defective part during coating, the coating film is irradiated with ultraviolet light so as to straddle the web in the width direction, fluorescent light from an irradiation region IR of the ultraviolet light is detected and the detected ultraviolet light is analyzed to identify a defective part of the coating film.

Description

  The present invention relates to a defect identification method and a defect identification system for identifying a defect portion in a coating film formed on a web surface.

  Conventionally, a process of forming a coating film on one surface or both surfaces of a long web according to the application or modifying the web by irradiating ultraviolet rays has been performed. As an example of such a processing apparatus, a long web wound in a roll shape is fed out and conveyed at a predetermined speed, and a coating liquid is applied to at least one surface of the conveyed web by applying a coating liquid. Generally, a coating apparatus provided with a coating means for forming is widely known.

  Here, when the coating liquid is applied to the web to be transported to form a coating film, uncoated parts, defects such as repellency and pinholes may exist in the coating film, and such defects exist. Then, a quality defect such as being unable to be used for a desired application occurs. Therefore, conventionally, a method for identifying a defective portion in a coating film is known from Patent Document 1 and the like. In this product, a fluorescent agent is included in the coating solution, and the coating film formed by applying the coating solution is irradiated with ultraviolet light, and the operator observes the coating film irradiated with ultraviolet light with the naked eye. To do. At this time, since the normal part in the coating film emits light but the defective part does not emit light, the defective part can be identified.

  By the way, in order to improve productivity, the width of the web (for example, 1 m or 3 m) is increased, and the web conveyance speed is increased (for example, 80 m / min). In such a case, it is practically impossible to identify all the defective portions by observation with the naked eye of the worker of the conventional example. Moreover, in the said conventional example, in order to improve the discriminability of a defect part with the naked eye, although the density | concentration of the fluorescent agent in a coating liquid is set high in the range of 0.1-5 mass%, It is very expensive, leading to high costs.

JP-A-5-157706

  In view of the above, the present invention provides a low-cost defect identification method and defect identification system capable of reliably identifying a defective portion of a coating film without omission even when the concentration of a fluorescent agent in a coating liquid is lowered. The issue is to provide.

  In order to solve the above problems, the defect identification method of the present invention for identifying a defect portion in a coating film while transporting a web having a coating film containing a fluorescent agent, The coating film is irradiated with ultraviolet light, fluorescence from an irradiation region of the ultraviolet light is detected, and the detected fluorescence is analyzed to identify a defective portion of the coating film. Here, in the defective part, not only the part where the coating liquid is not applied, but also the part where the coating liquid is once applied but the wettability with respect to the web is bad and the repelling occurs, the bubbles in the coating liquid and the coating It shall include pinholes caused by bumping of the liquid or dust or resin lump mixed in the coating liquid.

  In order to solve the above-described problem, the defect identification system of the present invention includes a conveying unit that conveys a web having a coating film containing a fluorescent agent, and a defect portion of the coating film that is provided in the conveyance path of the web. A defect identification device for identifying the light, a light irradiation means for irradiating the coating film with ultraviolet light, a detection means for detecting fluorescence from the irradiation region of the ultraviolet light, and the detected fluorescence. And an analysis means for analyzing a defective portion in the coating film.

  In the present invention, the light irradiating means includes at least two ultraviolet light lamps disposed opposite to the coating film forming surface of the web with an interval in the web conveyance direction, and from the ultraviolet light lamp. A condensing unit that collects ultraviolet light into a single band-shaped ultraviolet light, and the detection means includes an imaging unit, and the band-shaped ultraviolet light straddles the web in the width direction to form an irradiation region. It is preferable that the imaging unit is arranged immediately above or directly below the irradiation area.

  According to the present invention, in order to identify the presence or absence of a defective portion by detecting and analyzing the fluorescence from the irradiated region, a wider web is conveyed at a higher speed than in the conventional example observed with the naked eye of the operator. Even in this case, the defective part in the coating film can be identified without omission. In this case, if an irradiation area with high light intensity is created by ultraviolet light obtained by condensing ultraviolet light from an ultraviolet lamp, and the irradiation area is imaged and analyzed from directly above, an analysis in the coating film will be performed. Even when the concentration of the fluorescent agent is low, the contrast between the normal portion and the defective portion is increased, the defective portion can be identified more reliably, and the amount of expensive fluorescent agent used can be reduced, thereby reducing the cost. .

The perspective view which shows the defect identification system of embodiment of this invention. Sectional drawing which shows typically the positional relationship of the light irradiation means with respect to the web W, and a detection means. The figure which shows the contrast difference of a normal part and a defective part.

  Hereinafter, a coating means for applying a coating liquid containing a fluorescent agent to at least one surface of a conveying means for feeding a long web W with a feeding roll and feeding it at a predetermined speed with a driving roll. The defect identification system DM according to the embodiment of the present invention applied to the downstream side of the coating means in the transport path of the web W by a coating apparatus that is a web processing apparatus including a coating means that continuously forms CF will be described. In addition, since what has a well-known structure can be used as a coating apparatus, detailed description is abbreviate | omitted here.

  Referring to FIG. 1, the defect identification system DM includes a conveyance means T for conveying a web W having a coating film CF containing a fluorescent agent, and a defect identification device 1 provided in the conveyance path of the web W. The conveying means T includes not only a take-up roller for winding the illustrated web W but also an unillustrated feeding roller and driving roller. As the web W, a plastic film, paper, non-woven fabric, cloth, metal foil or the like can be used.

  The defect identification device 1 includes a light irradiation means 2 for irradiating the coating film CF with ultraviolet light, a detection means 3 for detecting fluorescence (reflected light) from the ultraviolet light irradiation area, and a coating based on the detected fluorescence. And analyzing means 4 for analyzing a defect portion in the film CF.

  With further reference to FIG. 2, the light irradiation means 2 includes a metal support frame 20 whose lower end is an open surface, and at least one (preferably a plurality of lines as described later) disposed in the support frame 20, In this embodiment, four) a substantially cylindrical fluorescent lamp type ultraviolet light lamp 21 and a light condensing unit 22 that condenses the ultraviolet light from each of the ultraviolet light lamps 21 to form a single belt-like ultraviolet light. Is provided. A socket (not shown) is provided on the side surface of the support frame 20 and is fixed by inserting the terminals of the respective ultraviolet light lamps 21 into the socket. As the ultraviolet lamp 21, a known lamp such as a mercury lamp, a metal halide lamp, or an ultraviolet LED (light emitting diode) can be used. As the condenser 22, a known lamp or the like can be used. Then, detailed explanation is omitted. With such a configuration, a single (one) band-shaped ultraviolet light collected by the light collecting unit 22 straddles the web W in the width direction (that is, has a width wider than the width of the web W). An irradiation region IR having a high light intensity is configured.

  The number of the ultraviolet lamps 21 is preferably 2 to 10, for example, and more preferably 4 to 6. When the number of the ultraviolet lamps 21 is less than two (that is, one), a sufficient amount of light may not be obtained because the fluorescent agent emits light. In the case where a sufficient amount of light can be obtained in the irradiation region, one ultraviolet lamp 21 may be used. On the other hand, if the number exceeds 10, the space for installing the ultraviolet light lamp 21 becomes large, leading to an increase in the size of the defect identification system DM, which may not be installed in an existing web processing apparatus. The shape of the ultraviolet light lamp may be not only a fluorescent lamp type but also a bulb type. In this case, a plurality of ultraviolet light lamps are arranged in series in the width direction of the web W so that a strip-shaped irradiation region is formed, and the light bulb type ultraviolet light lamps arranged in series are regarded as one.

  A belt-like slit 23 extending in the width direction of the web W is opened (opened) on the upper surface 20a of the support frame 20 located immediately above the irradiation region IR, and the detection means faces the irradiation region IR through the slit 23. 3 is arranged. The detection means 3 is connected to the analysis means 4 with a cable. As the detection unit 3, a known imaging unit (imaging device) such as a CCD camera or a CMOS camera can be used, and as the analysis unit 4, a known personal computer or the like that can perform arithmetic processing is used. it can. Note that the number of imaging units can be set as appropriate according to the width of the web W. With the imaging unit arranged in this way, it is possible to detect and image the reflected light from the coating film CF in the irradiation region IR with high light intensity. Here, since the coating film CF contains a fluorescent agent as described above, a normal portion of the coating film CF irradiated with ultraviolet light emits light, whereas a defective portion in the coating film CF does not emit light. Therefore, the analysis unit 4 performs known arithmetic processing on the image of the coating film CF imaged by the imaging unit serving as the detection unit 3, and identifies the defective part by causing a difference in contrast between the normal part and the defective part. (See FIG. 3). The detection means 3 may be provided so as to face the irradiation region IR obliquely from the outside of the support frame 20 instead of directly above the irradiation region IR, and further, a slit is opened on the side surface of the support frame 20 or on the oblique side surface. You may provide so that the irradiation area | region IR may be faced from the slit.

  Next, using the defect identification system DM, the coating CF formed on the surface of the web W by the coating apparatus is used as an adhesive layer, and the defect portion in the adhesive layer CF is identified as an example. A form defect identification method will be described.

  First, the web W is fed out using a feeding roller (not shown), and a coating liquid containing a fluorescent agent and an adhesive main agent is applied to the surface of the web W while conveying the web W using a driving roller (not shown). Then, an adhesive layer CF containing a fluorescent agent is formed. Here, the density | concentration of the fluorescent agent in a coating liquid is lower than the density | concentration (0.1-5 mass%) in the case of the said macroscopic observation of the said prior art example, within the range of 0.001-0.05 mass%. It is preferable to set, and it is more preferable to set within the range of 0.002 to 0.03 mass%. If the amount is less than 0.001% by mass, sufficient light emission for detecting fluorescence may not be obtained by the detection means 3, whereas if it exceeds 0.05% by mass, the coating liquid is about to be applied. In addition to the possibility of impairing the function, the cost of the coating liquid is increased, which is not preferable from an economical viewpoint. Fluorescent agents include dyes that absorb ultraviolet light and emit fluorescence, such as stilbene, diaminostilbene, quinazolone, perylene, coumarin, diaminodiphenyl, imidazole, thiazole, oxazole, triazole, carbazole , Pyridine, naphthalic acid, imidazolone, naphthalimide, and thiophene dyes, and at least one selected from fluorogens such as fluorescein, thioflavine, eosin, rhodamine, and terphenyl can be used. . As other components of the coating liquid, known ones can be appropriately selected according to the application, and thus detailed description thereof is omitted here.

  The preferable range of the blending amount (content) of the fluorescent agent in the coating film is the same as the concentration in the coating solution in the wet state before drying. The range of 0.005-0.5 mass% is preferable and, as for fluorescent agent content in the coating film after drying, the range of 0.010-0.3 mass% is more preferable. If the content of the fluorescent agent in the coating film after drying is less than 0.005% by mass, there may be a case where sufficient fluorescence for detecting fluorescence by the detection means 3 cannot be obtained. On the other hand, if it exceeds 0.5% by mass, not only the function imparted to the coating film may be impaired, but also the production cost is increased, which is not economical.

  While transporting the web W on which the adhesive layer CF is formed in this way, the adhesive layer CF is irradiated with at least one band-like ultraviolet light from the light irradiation means 2 (this band-like ultraviolet light is condensed and the irradiation region IR is focused). create). At this time, since the adhesive layer CF contains a fluorescent agent, the normal part of the adhesive layer CF irradiated with ultraviolet light emits light, whereas the defective part does not emit light. Then, the imaging unit 3 detects (images) the fluorescence (reflected light) from the irradiation region IR, and the analysis unit 4 performs a known calculation process on the image captured by the imaging unit 3 and uses the contrast difference. Identify the presence or absence of a defect. If it is identified that there is a defective part, an image including the defective part may be stored in a storage unit (not shown) included in the analysis unit 4. Here, since the irradiation region IR obtained by condensing ultraviolet light from each of the plurality of ultraviolet light lamps 21 has high light intensity, even when the concentration of the fluorescent agent in the coating liquid is low, FIG. As shown in FIG. 3, the contrast difference between the normal part and the defective part can be increased, and the defective part can be identified with certainty. Therefore, since the usage-amount of an expensive fluorescent agent can be reduced, cost can be suppressed.

  Next, in order to confirm the effect of the present invention, the following experiment was performed. In this experiment, a coating solution for forming the adhesive layer CF was prepared by the following method. That is, 100 parts by mass (solid content 60 wt%) of the adhesive main agent (Mitsui Chemicals “Takelac A-1143”), 11 parts by mass (solid content 75 wt%) of the curing agent (Mitsui Chemicals “Takenate A-50”), 0.1 parts by weight of fluorescent agent (“TINOPAL OB” manufactured by BASF Japan) (solid content: 100 wt%) is further blended and further diluted with 300 parts by weight of a diluent solvent (“Methyl ethyl ketone” manufactured by Maruzen Petrochemical Co., Ltd.) Was prepared. At this time, the blending amount of the fluorescent agent with respect to the total mass of the coating liquid (hereinafter referred to as “fluorescent agent concentration”) was 0.024 mass%. This coating solution was applied to a polyethylene terephthalate web W having a thickness of 125 μm by the Meyer bar method to form an adhesive layer CF having a thickness of 5.0 μm. At this time, the conveyance speed of the web W was 80 m / min, the coating width was 1 m, and the coating length was 1000 m. In this 1000 m long adhesive layer CF, 100 defective portions (uncoated portions) were intentionally randomly formed. The web 1 having the adhesive layer CF containing the fluorescent agent thus formed was used as a sample 1. Furthermore, the coating amount was prepared by changing the blending amount of the fluorescent agent to 0.05 parts by mass and 0.01 parts by mass (the concentration of the fluorescent agent at this time was 0.012% by mass and 0.0024% by mass, respectively) Except for, the adhesive layers obtained in the same manner as in the above sample 1 were designated as sample 2 and sample 3, respectively. Further, the above sample was prepared except that 0.05 part by mass of “O-AN” manufactured by Nippon Fluorescent Chemical Co., Ltd. was used as the fluorescent agent to prepare a coating liquid (the fluorescent agent concentration at this time was 0.012% by mass). The adhesive layer obtained by the same method as in Example 1 was used as Sample 4. When 100 defect portions formed on each of the samples 1 to 4 were identified using the defect identification system DM (the web conveyance speed was 80 m / min), as shown in Table 1, all (100) Thus, it was confirmed that the defective portion could be identified without omission (that is, the identification rate was 100%). On the other hand, when the sample 1 was observed with the naked eye (visually) by an operator as in the conventional example, it was confirmed that only 53 defective portions could be identified among 100 defective portions. In addition, except for the point that 0.005 parts by mass of the fluorescent agent was blended to prepare a coating solution (the fluorescent agent concentration at this time was 0.0012% by mass), the adhesive layer CF obtained in the same manner as the sample 1 was used as a sample. When 100 defect portions formed on the sample 5 were identified in the same manner, 87 defect portions could be identified, and it was confirmed that an identification rate higher than that of the naked eye (viewing) was obtained. Note that “FLR72T6BLB / M” manufactured by NIPPO was used as the ultraviolet light lamp 21 of the defect identification system DM used in the above experiment, and “LSC-4000” manufactured by MEC was used as the detection means 3 and the analysis means 4.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the case where the coating liquid for adding the fluorescent agent to the coating liquid for forming the adhesive layer is applied to form the coating film CF has been described. The present invention can also be applied to the case where a coating film is formed by applying a coating solution containing an ink receiving agent and other functional agents to which a fluorescent agent is added.

  In the above-described embodiment, the case where the fluorescent agent is contained in the coating liquid to be applied to the web has been described. However, the present invention is also applicable to the case where the fluorescent agent is contained in the molten resin of the plastic film film or the paper stock. The invention can be applied. In this case, while transporting plastic film or paper (hereinafter referred to as “film, etc.”), the film, etc. is irradiated with ultraviolet light, the fluorescence from the irradiated area is detected, and the detected fluorescence is analyzed to detect defects in the film, etc. The part can be identified. In addition, the density | concentration of the fluorescent agent in molten resin or paper stock can be set similarly to the density | concentration of the fluorescent agent in the said coating liquid.

  In the above-described embodiment, the case where the defect identification system is applied to the coating apparatus has been described. However, the defect identification system is applied to other web processing apparatuses that perform predetermined processing on a coating film formed on the web surface. Examples of other web processing apparatuses include a cutting apparatus, a film forming apparatus, a paper making apparatus, a laminating apparatus (laminator), an inspection apparatus, and a UV irradiation apparatus.

  Moreover, although the said embodiment demonstrated the case where the presence or absence of the defect part in a coating film was analyzed based on the fluorescence (reflected light) detected from the light irradiation means 2 side (upper side) of the web W, the light of web W Fluorescence (transmitted light) may be detected from the side opposite to the irradiation means 2 (lower side), and the presence / absence of a defective portion in the coating film may be analyzed based on the detected fluorescence. In this case, the detection means may be disposed immediately below the irradiation area.

  DM: Defect identification system, W: Web, CF ... Coating film, 1 ... Defect identification device, 2 ... Light irradiation means, 3 ... Detection means (imaging part), 4 ... Analysis means, T ... Winding roller (conveyance means) , 21... Ultraviolet lamp, 22... Condensing part, IR.

Claims (2)

A defect identification method for identifying defects in a coating film while conveying a web having a coating film containing a fluorescent agent,
Irradiating the coating film with ultraviolet light so as to straddle the web in the width direction, detecting fluorescence from the irradiation region of the ultraviolet light, and analyzing the detected fluorescence to identify defective portions of the coating film A feature defect identification method. Conveying means for conveying a web having a coating film containing a fluorescent agent;
A defect identification device provided in a web conveyance path for identifying a defective portion of the coating film;
The defect identification device comprises a light irradiation means for irradiating the coating film with ultraviolet light, a detection means for detecting fluorescence from the irradiation area of the ultraviolet light, and analyzes a defect portion in the coating film based on the detected fluorescence. A defect identifying system comprising: an analyzing means for performing