JP5781822B2 - Adhesive application state inspection method - Google Patents

Description

The present invention relates to an adhesive application state inspection method for measuring the application state of a lamination adhesive applied to an aluminum foil surface.

  Various composite packaging sheets have been developed that make use of the advantages of each material by bonding other materials such as paper and plastic to aluminum foil. For example, when a non-porous plastic film is bonded to an aluminum foil, an aluminum foil having a relatively low strength is reinforced, and a packaging sheet having excellent moisture resistance and the like can be obtained at the same time. This type of packaging sheet is widely used, for example, for PTP (press through package) in which a medicine tablet or capsule is accommodated in a recess of a container sheet and the opening of the recess is closed by the packaging sheet.

  As a method for bonding a nonporous plastic film to an aluminum foil, for example, there is a dry bonding method. In the dry bonding method, the adhesive is applied to the surface of the aluminum foil with an adhesive application device, and the solvent component in the adhesive is removed by passing through the drying device, and then the aluminum foil is bonded using the film application device. A plastic film is heated and pressure-bonded to the agent application surface to obtain a laminated packaging sheet. In the case of this method, it is required that the adhesive on the surface of the aluminum foil is thinly and evenly attached at the stage of being carried into the film sticking apparatus. However, the amount of coating when applying the liquid adhesive to the aluminum foil is required. Due to fluctuations and changes in viscosity and concentration that occur in the process of scattering of solvent components in the adhesive during drying, there is a risk of unevenness in the amount of residual solids deposited. There was a problem that poor adhesion sometimes occurred.

  In order to prevent such uneven coating of the adhesive from occurring, for example, as disclosed in Patent Document 1, studies are being made to improve the configuration and control method of the adhesive application device. The effect is not sufficient, and the configuration of the apparatus is complicated, and the existing adhesive application apparatus cannot be modified and applied.

  Therefore, in general, when the application state of the adhesive on the surface of the aluminum foil is visually inspected before the plastic film is attached, and an area with uneven coating is found, it is indicated that "There is a defective area in this area". An identification label to be displayed was attached, and the part was lined out in a later process to prevent a poorly bonded packaging sheet from flowing out to the market.

  Patent Document 2 is a method for inspecting food packaging products covered with a packaging sheet in which a laminate film such as a plastic film is bonded to an aluminum foil, and the packaging sheet is subjected to a heat change from the outside, An inspection method is disclosed in which a temperature difference generated due to a heat capacity at which a foreign matter adhering portion of a packaging sheet is different from other portions is measured by an infrared detector, and the presence or absence of foreign matter adhering to the packaging sheet is determined.

JP-A-6-262111 JP 62-28650 A

  When visually inspecting the state of the adhesive on the surface of the aluminum foil, the adhesive is almost transparent and easily affected by the color tone of the aluminum bullion and the reflection of light. It was difficult to make an accurate pass / fail judgment.

  In addition, the inspection method for the presence or absence of foreign matter in Patent Document 2 is a method for detecting the presence or absence of foreign matter attached to a finished product packaging sheet, and a method for preventing poor adhesion between an aluminum foil and a laminate film. is not.

The present invention has been made in view of the above-described background art, and can be easily used in an existing lamination device, and can be applied with an adhesive capable of accurately detecting the application state of the adhesive on the surface of the aluminum foil. An object is to provide a state inspection method .

In this invention, a lamination adhesive is applied to the surface of the aluminum foil, and after removing the solvent component of the adhesive by heating, a sheet material such as a plastic film is pressure-bonded to the adhesive-coated surface of the aluminum foil. Before, with respect to the adhesive-coated surface of the aluminum foil surface, the temperature of a plurality of coordinate points located in the width direction with respect to the feeding direction of the aluminum foil is measured by an infrared temperature measuring device, and individual measurement at the plurality of coordinate points is performed. When the temperature is equal to or lower than a predetermined reference value, the first determination for determining that there is uneven application of the adhesive and the average value in the partial range in the width direction for the measured temperatures at the plurality of coordinate points This is a method for inspecting the application state of the adhesive , in which when the average value is equal to or less than a predetermined reference value, a second determination is made to determine that there is uneven application of the adhesive.

Each reference value used for the first and second determination, in the width direction, it is preferable to set higher than the side edge portions of the central portion of the aluminum foil.

The adhesive application state inspection method of the present invention utilizes the fact that the heat capacity of the adhesive on the aluminum foil surface becomes partially uneven if there is uneven application of the adhesive on the aluminum foil surface. Can be detected quantitatively with high accuracy. Therefore, the variation of the operator's judgment in the conventional visual inspection is eliminated, and an objective and accurate inspection can be performed.

  In addition, because the adhesive unevenness determination is performed at the stage after the solvent component of the adhesive is removed by the drying device, that is, immediately before being attached to the other plastic film, poor adhesion of the packaging sheet It is possible to accurately inspect the adhesion state of the resin component of the adhesive, which is an important factor.

Furthermore , in the case of the inspection method of Patent Document 2 of the above background art, it is necessary to provide a dedicated heating means for heating the aluminum foil to cause a temperature difference on the surface. Since the temperature of the aluminum foil heated by this drying apparatus is measured, it is not necessary to newly provide a heating means, and it can be easily attached to an existing lamination apparatus.

It is a schematic diagram which shows the structure of the lamination apparatus in which one Embodiment of the application | coating state inspection method of the adhesive agent of this invention is used . It is a graph which shows the temperature distribution between the image data of the A section measured by infrared thermography, and A1-A2 of this image data.

Hereinafter, an embodiment of an adhesive application state inspection method according to the present invention will be described with reference to the drawings. The lamination apparatus 10 shown in FIG. 1 is a packaging sheet 18 which is a composite packaging sheet by attaching a sheet material such as a plastic film 16 to one surface of an aluminum foil 12 via a lamination adhesive 14. Is a device that performs lamination by a dry bonding method.

  The aluminum foil 12 thrown into the lamination apparatus 10 is continuously wound in a roll shape with a constant width, and is sent out from the roll. The plastic film 16 is, for example, a synthetic resin sheet such as polyvinyl chloride resin (PVC), polypropylene resin (PP), and nylon, and is continuously wound in a roll with a constant width similar to that of the aluminum foil 12. , And sent out to the lamination device 10 from the roll. The adhesive 14 is diluted with a solvent in which a main component adhesive resin such as a vinyl chloride-vinyl acetate copolymer, a modified polyester resin, an epoxy resin, or a urethane resin is added at a mixing ratio of several tens of percent, and has a constant flow. It has sex. The adhesive 14 is placed in a container 15 having an upper opening.

  As shown in FIG. 1, the lamination device 10 includes an adhesive application device 18, a drying device 20, and a film sticking device 22. The adhesive applicator 28 is configured such that the gravure roll 24 partially immersed in the adhesive 14 rotates, and the adhesive is applied to the lower surface of the aluminum foil 12 that is continuously fed to the presser roll 26. 14 is applied. The adhesive 14 is diluted with a solvent and has good fluidity, and is very thin and spreads almost uniformly so as to cover the surface of the aluminum foil 12.

  The drying device 20 has a tunnel furnace-like structure with both ends open, and the aluminum foil 12 coated with the adhesive 14 is fed from the inlet 20a, and the aluminum foil 12 and the adhesive 14 are heated in a high temperature atmosphere. Then, after removing the solvent and moisture in the adhesive 14, it is sent out from the outlet 20b, and only the solid component which is the main component remains on the adhesive coating surface on the surface of the aluminum foil 12 sent out from the outlet 20b. To do. The thickness of the residual solid content varies depending on the thickness of the aluminum foil 12 and the use of the packaging sheet, and is set in a range of approximately 0.1 to 10 μm.

  The aluminum foil 12 sent from the drying device 20 is guided by the guide roll 27 and sent to the film sticking device 22. In particular, the guide roll 27 is preferably a roll whose surface is made of rubber so as to reflect infrared rays emitted from surrounding machines and illumination so as not to enter an infrared thermography 38 described later.

  The film sticking device 22 heats the surface of the aluminum foil 12 delivered from the drying device 20 on the side where the adhesive 14 is not applied by the heated steel roll 28, and softens the adhesive 14. At the same time, the plastic film 16 is continuously fed so as to face the adhesive application surface, and the aluminum foil 12 and the plastic film 16 are passed between the heated steel roll 28 and the rubber roll 30 and are pressed. Thereafter, the softened adhesive 14 is cooled by a cooling roll 32 and cured, and the resulting packaging sheet 34 is wound into a roll.

  The application state inspection device 36 is attached to the subsequent stage of the drying device 20 of the lamination device 10. The application state inspection device 36 detects the application state of the adhesive 14 based on the infrared thermography 38 which is an infrared temperature measurement device installed in the vicinity A of the outlet 20 b of the drying device 20 and the measurement temperature of the infrared thermography 38. Detection means such as a monitor or a computer (not shown) is provided. The detection unit includes a determination unit 40 that analyzes the measurement temperature of the infrared thermography 38 and determines whether the adhesive 14 is applied or not.

  The infrared thermography 38 includes an infrared camera incorporating an infrared image sensor, is installed on the adhesive application surface side of the aluminum foil 12 that is continuously sent out from the outlet 20b, and applies the adhesive that passes through part A shown in FIG. The infrared energy radiated from the surface is measured at a plurality of coordinate points, the measurement data at each coordinate point is converted into temperature, and the temperature distribution is displayed as an image. In the part A which is the measurement position, the guide roll 27 is not reflected in the image of the adhesive coating surface of the aluminum foil 12 imaged by the infrared thermography 38. As shown in FIG. 2, the temperature distribution image data 39 on a monitor (not shown) is converted into a color difference in the measured temperature, and the temperature distribution is displayed as a color distribution.

  The determination unit 40 selects a coordinate point on a line connecting between A1 and A2 that is substantially perpendicular to the feeding direction of the aluminum foil 12 among the plurality of coordinate points measured by the infrared thermography 38, and determines each coordinate point. By comparing the measurement temperature with the reference temperature (T1, T2 or T3), it is determined whether the adhesive 14 is applied on the surface of the aluminum foil 12, that is, whether the adhesive solid 14 is attached.

  The aluminum foil 12 and the adhesive 14 are heated in a high-temperature atmosphere in the drying device 20 and are uniformly in a high-temperature state as a whole. When the aluminum foil 12 and the adhesive 14 are sent from the outlet 20b into the indoor atmosphere, the temperature starts to decrease.

  Since the aluminum foil 12 itself is a metal, the heat capacity is very small, but the solid content of the adhesive 14 made of synthetic resin has a larger heat capacity than the aluminum foil 12. Therefore, since the heat capacity of the portion where the resin component of the adhesive 14 is thinly attached is relatively small, when the ambient temperature is lowered, the temperature of the portion quickly follows and falls. On the other hand, since the heat capacity of the part where the solid content of the adhesive 14 is thickly attached becomes large, the temperature of the part decreases relatively slowly when the ambient temperature decreases.

  For the area where the adhesive 14 on the surface of the aluminum foil 12 is not unevenly coated and the residual solid content of the adhesive 14 is evenly adhered, the temperature is uniform when sent out from the outlet 20b into the room atmosphere. The temperature distribution in the region becomes almost uniform. On the other hand, in the region where the adhesive 14 has uneven coating and the amount of the residual solid content of the adhesive 14 is non-uniform, when it is sent from the outlet 20b into the room atmosphere, the heat capacity is large. Since a difference occurs in the rate of temperature decrease in a small portion, the temperature distribution in the region becomes non-uniform.

As shown in FIG. 2, the determination means 40 divides A1-A2 into regions 1, 2, and 3, and reference temperatures T1, T2, and T3 are set for each region. Then, the determination means 40 compares the measured temperature of the coordinate point between A1 and A2 measured by the infrared thermography 38 with the reference temperatures T1, T2, and T3, and when the measured temperature is lower, “This coordinate point is bonded. adhesion amount of the solid content of agent 14 is small, "and determining (first determination). Further, the determination means 40 calculates an average value in a partial range in the width direction for the measured temperature at each coordinate point, compares this average value with the reference temperatures T1, T2, T3, and determines the measured temperature. Is low, it is determined that “the amount of solid content of the adhesive 14 is small in this region” (second determination). The reference value used for the second determination may be different from the reference value used for the first determination. By performing the second determination, it is possible to mask the influence of noise when irregular noise is superimposed on the measurement temperature of the infrared temperature measurement device and an error occurs. When the first determination or the second determination determines as described above, an alarm signal indicating abnormality is output. The alarm signal is a buzzer for notifying the operator of an abnormality or an electric signal for notifying the peripheral device of the abnormality, and is not particularly limited.

  Here, the reference temperatures T1, T2, and T3 are set so that T1≈T3 <T2. For example, when the width of the aluminum foil 12 is wide, when the aluminum foil 12 is fed from the outlet 20b of the drying device 20, the temperature at the left and right end portions of the aluminum foil 12 tends to decrease faster than the temperature at the center portion. Therefore, in this determination means 40, different reference temperatures T1, T2, and T3 are set for each of the regions 1, 2, and 3, and the influence of the difference in speed at which the temperature decreases is corrected to thereby apply the adhesive 14. The accuracy of pass / fail judgment is improved.

As described above , according to the adhesive application state inspection method of this embodiment, the heat capacity of the aluminum foil 12 becomes partially uneven when there is uneven coating of the adhesive 14 on the surface of the aluminum foil 12. It is possible to detect the degree of coating unevenness of the adhesive 14 quantitatively with high accuracy. Therefore, the variation of the operator's judgment in the conventional visual inspection is eliminated, and an objective and accurate inspection can be performed.

  Moreover, since the quality determination of the coating unevenness of the adhesive 14 is performed at a stage after the solvent component of the adhesive 14 is removed by the drying device 20, that is, immediately before being attached to the other plastic film 16. In addition to the effect of fluctuations in the coating amount when the adhesive 14 diluted with the adhesive application device 18 is applied, there is also the effect of changes in viscosity and concentration that occur in the process of scattering the solvent component of the adhesive 14 in the drying device 20. In addition, it is possible to directly inspect the adhesion state of the residual solid content of the adhesive 14 which is an important factor of the adhesion failure of the packaging sheet 34.

In addition, the application | coating state inspection method of the adhesive agent of this invention is not limited to the said embodiment. For example, if it is not necessary to display temperature measurement data as an image on a production line or the like, another infrared temperature measurement device that does not have an image display function can be used instead of the infrared thermography 38. The sheet material to be bonded to the aluminum foil may be paper, cellophane, other aluminum foil or other metal foil in addition to the plastic film.

  Further, a line sensor capable of detecting infrared rays as an infrared temperature measuring device is arranged at right angles to the feeding direction of the aluminum foil, and the infrared intensity can be measured on the A1-A2 line as described above. By sampling the output of each element of the sensor at a predetermined timing, the same processing as described above can be performed.

  Moreover, the reference value for determining the application state of the adhesive may be a predetermined constant temperature, but the average temperature or the average temperature is constant based on the average temperature of the adhesive application surface in the measurement range. The determination may be made by setting the temperature minus the temperature as a reference value.

  In the case of the determination means 40 of the above-described embodiment, correction is performed by setting different reference temperatures T1, T2, and T3 for the regions 1, 2, and 3, but this is only an example of a correction method. For example, when there is no need to correct the reference temperature for each region due to the thickness of the aluminum foil, the material and thickness of the applied adhesive, the temperature in the drying device, the room temperature, etc., the same for all coordinate points A reference temperature can be set. On the contrary, it is also possible to make a more strict pass / fail judgment by further dividing the region and setting an appropriate reference temperature for each region.

DESCRIPTION OF SYMBOLS 10 Lamination apparatus 12 Aluminum foil 14 Adhesive 16 Plastic film 18 Adhesive coating apparatus 20 Drying apparatus 20a Inlet 20b Outlet 22 Film sticking apparatus 34 Packaging sheet 36 Application state inspection apparatus 38 Infrared thermography 40 Determination means

Claims (2)

After applying an adhesive for lamination on the surface of the aluminum foil, heating and removing the solvent component of the adhesive, and before pressing the sheet material on the adhesive-coated surface of the aluminum foil, For the adhesive application surface , the temperature of a plurality of coordinate points located in the width direction with respect to the feeding direction of the aluminum foil is measured by an infrared temperature measuring device,
A first determination for determining that there is uneven application of the adhesive when individual measured temperatures at the plurality of coordinate points are equal to or less than a predetermined reference value ;
For the measured temperatures at the plurality of coordinate points, an average value in a partial range in the width direction is calculated, and when the average value is a predetermined reference value or less, it is determined that there is uneven application of the adhesive. A method for inspecting an application state of an adhesive, wherein the second determination is performed . Wherein the first and the reference value used for the second determination, the in the width direction of the aluminum foil, a central portion coated state inspection of the adhesive of claim 1, wherein the higher than a side edge portion of the aluminum foil Method.

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