JP2005172646A - Drying characteristic detection method and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device capable of measuring a drying characteristic of a paint film directly and accurately in a noncontact way, and shortening a drying time. <P>SOLUTION: This drying characteristic detection device is equipped with an electromagnetic wave irradiation means for irradiating the paint film to be measured with an electromagnetic wave, an electromagnetic wave detection means for detecting the electromagnetic wave reflected from the paint film to be measured, an operation means 4 for operating the detected electromagnetic wave characteristic, and a display means 6 for displaying an operation result. In the device for evaluating the drying characteristic of the paint film to be measured, the electromagnetic wave irradiation means is used as an infrared light source 1, and a storage device 5 for storing a calibration curve between the infrared absorbance and the solvent content of various solvents measured beforehand is provided, and the infrared absorbance of an infrared ray reflected or transmitted from the paint film to be measured is measured by using the electromagnetic wave detection means as an infrared spectral analyzer 3, and the operation means operates by collating the measured infrared absorbance with the calibration curve stored in the storage device 5, and calculates the solvent content in the paint film to be measured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a drying characteristic detection device for calculating the drying characteristics of a coating film by calculating the content of the drying characteristics of a paint, an adhesive, etc. from the infrared absorption spectrum of a substance that decreases as the degree of drying progresses. .

Conventionally, in order to evaluate the drying characteristics of coatings, adhesives, etc., the hardness of the film is observed by a pencil hardness test, and the drying characteristics are observed, or the film is covered with gauze, and then a weight is placed on it. There are methods based on JIS standards, such as a method of checking the drying characteristics based on how gauze adheres to the film, and evaluation methods using finger touch.
However, in these methods for evaluating drying characteristics according to JIS standards, the coating film is torn and marks remain after the test. Further, depending on the properties of the coating film, there is a problem that the difference between the dried and undried states does not appear remarkably and the timing of completion of drying is not clearly understood. In making these evaluations, when setting the apparatus and observing the passage of time, drying progresses during that time, and thus highly reliable evaluation cannot be performed.
Therefore, the time change in the dry state appears prominently, and instead of the above evaluation method as an evaluation method that does not leave a trace on the coating film surface, the reduction rate is due to the time change of the weight reduction amount of the coating film applied to the monitor material. A method of determining the end of drying when a certain specified value is reached can be considered. FIG. 8 shows the time change of the weight reduction rate after applying a vinyl chloride resin-based enamel paint on an aluminum foil as a monitor material. When completely dried, the weight of the paint is reduced to about 60% of the initial weight. Sample 1 and sample 2 were the same paint, and the temperature and humidity conditions were all the same, but the initial weight could not be measured accurately, so there was a difference in the weight loss rate.
As a method for evaluating the dry state in a non-contact manner instead of using a monitor material, a method of irradiating the coating film with infrared rays, which are electromagnetic waves, and measuring the light intensity of the reflected wave due to the flatness has been proposed (for example, Patent Document 1).
JP 2002-39723 A

However, in the past, when drying these materials in processes that require drying, such as coating work and bonding work, the timing for ending the drying work is not clear, and drying takes excessive time to complete the drying completely. I was letting. Since the operation is stopped while spending time in the drying operation, the production efficiency is poor, and a method for knowing the drying characteristics and managing the drying time is required.
However, in order to evaluate the drying characteristics, the method of following the change over time of the weight reduction amount of the film is generally very small compared to the workpiece, so it is possible to accurately measure the weight of only the film. Can not. Therefore, it can only be experimentally evaluated by applying it to a light weight alternative monitor material.
In addition, the evaporation rate of a highly volatile solvent is the fastest immediately after coating, and the initial weight of the coating film is reduced during measurement, resulting in an error in the measured value. Therefore, the weight loss calculated by this method is about several percent. An error occurs. Since the properties of the coating film at the end of drying differ depending on the subtle difference in the solvent content, the value calculated from the reduction rate relative to the initial weight contains an error, and the coating properties are obtained. I couldn't.
Also, in the method of evaluating the dry state by irradiating infrared rays and measuring the light intensity of the reflected wave according to the flatness, the coating film with various colors has a different light reflection intensity and has an accurate dryness. It cannot be measured.
Therefore, an object of the present invention is to provide a method and an apparatus that can directly and accurately measure the drying characteristics of a coating film in a non-contact manner and can shorten the drying time.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 is a drying property detection method for irradiating an electromagnetic wave to a film to be measured and detecting the reflected electromagnetic wave to evaluate the drying characteristic of the film to be measured. A calibration curve of the measured infrared absorbance and solvent content of various solvents was stored, and then the infrared absorbance of infrared reflected or transmitted from the coating film to be measured was measured, and the measured infrared absorbance was stored. The solvent content in the coating film to be measured is calculated by collating with a calibration curve.
According to a second aspect of the present invention, there is provided an electromagnetic wave irradiation means for irradiating the film to be measured with an electromagnetic wave, an electromagnetic wave detection means for detecting the electromagnetic wave reflected from the film to be measured, and an operation for calculating the detected electromagnetic wave characteristics. And a drying means for evaluating the drying characteristics of the coating film to be measured, wherein the electromagnetic wave irradiation means is an infrared light source, and the infrared absorbances and solvents of various solvents measured in advance are used. A storage device for storing a calibration curve of the content is provided, and the infrared ray reflected or transmitted from the coating film to be measured is measured using the electromagnetic wave detecting means as an infrared spectroscopic analyzer, and the calculating means measures the infrared absorbance measured. Is calculated by comparing with a calibration curve stored in the storage device to calculate the solvent content in the coating film to be measured.
According to a third aspect of the present invention, the infrared spectroscopic analyzer includes a movable transmission type or reflection type probe corresponding to the shape of the coating film to be measured.

According to the first and second aspects of the invention, since the infrared absorption spectrum is detected and the content of each substance in the coating film is calculated, the material composition ratio at that time can be calculated, and the drying characteristics of the coating film can be calculated. It is possible to know directly and the end of drying can be judged by the drying characteristics.
According to the third aspect of the invention, since the movable transmission type or reflection type probe is provided, it can be used in a production line that handles a small amount of workpieces according to the shape and characteristics of the sample. Since the drying characteristics of the coating applied to the workpiece can be obtained directly, it is not necessary to dry excessively, and the drying time can be shortened.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a drying characteristic detection apparatus according to a first embodiment of the present invention, in which 1 is an infrared light source, 2 is an infrared light receiving unit, and 3 is a Fourier transform infrared spectroscopy analyzer. Reference numeral 5 denotes a storage device for storing calibration curve data, and reference numeral 4 denotes an arithmetic unit for calculating the content of the coating film solvent and determining the coating film drying characteristics. Further, the drying characteristics of the coating film calculated by the arithmetic device 4 can be confirmed at any time by the display unit 6.

Next, the operation of the embodiment of the present invention will be described with reference to FIG.
FIG. 2 is a flow showing a process of dryness detection by the dry characteristic detection apparatus of the present invention. (ST1) First, a calibration curve is created.
A calibration curve between the solvent concentration and the infrared absorbance of the standard sample is obtained by the gas chromatograph analyzer and the infrared spectroscopic analyzer 3.
(ST2) Next, the obtained calibration curve data is stored in the storage device 5.
(ST3) The coating film is irradiated with infrared light from the infrared light source 1 and the light receiving unit 2 receives reflected infrared light.
(ST4) The infrared absorption spectrum of the received infrared absorption spectrum is measured by a Fourier transform infrared spectroscopy analyzer 3.
FIG. 3 is a schematic diagram of the infrared absorption spectrum of the coating film detected by the Fourier transform infrared spectroscopic analyzer 2 of the drying characteristic detector according to Example 2 of the present invention. Here, the three types of solvents A, B, and C and the dryness are shown. Spectra caused by each of the functional groups A that are not affected by are detected.
The functional group A was vinyl chloride, and the solvents A, B, and C were substances made of toluene, acetone, and methanol, respectively.
(ST5) The content of the solvent is calculated by the calculation device 4.
From the data in the storage device 5 and the detected infrared absorption spectrum, the content of the coating film solvent is calculated by the arithmetic device 4. FIG. 4 is a schematic diagram of a calibration curve showing the absorbance ratio of the solvent A, B, C concentration and the functional group A of each solvent. By applying the absorbance ratio obtained from the infrared absorption spectrum to this calibration curve, The concentration of can be accurately known.
(ST6) The dryness is calculated by the calculation device 4.
By calculating the content of each substance in the coating film, the material composition ratio at that time is calculated, and the drying characteristics of the coating film are calculated. FIG. 5 is a diagram showing the change over time of the measured solvent A, B, and C concentrations. As shown in the figure, the concentration of each solvent decreases with time, and when the concentration falls below a certain value, the drying of the coating film is completed.
(ST7) The calculation result is displayed on the display unit 6.
The display unit 6 displays the result of determining the drying characteristics of the coating film from the content of the coating film solvent.

  Thus, by detecting the infrared absorption spectrum and calculating the content of each substance, it is possible to know the solvent concentration and determine the end of drying. Since it is not necessary to dry excessively as in the conventional example, the work time can be greatly shortened in the work of painting the casing.

  FIG. 6 is a block diagram of a drying characteristic detection apparatus according to Embodiment 3 of the present invention. A coated monitor material is installed between the light source 1 and the light receiving unit 2, and infrared rays from the light source 1 are transmitted through the monitor material, and then detected by the light receiving unit 2. Further, the drying characteristics of the coating film calculated by the arithmetic device 4 can be confirmed at any time by the display unit 6. The infrared absorption spectrum inside the coating film can be detected from the transmitted infrared ray, and the content of each substance inside the coating film can be calculated. Therefore, even if there is a difference in the drying behavior between the surface and the inside of the coating film with a thickness of about 50 μm, it is possible to know the concentration of the solvent and judge the end of drying, so there is no need to dry excessively, and the drying time is reduced. It can be shortened.

In this embodiment, as shown in FIG. 7, both the light source 1 and the light receiving unit 2 are movable, and the irradiation direction of infrared rays can be adjusted. Therefore, since the infrared absorption spectrum can be measured regardless of the shape of the workpiece, the drying characteristics of the coating film applied to the workpiece having a convex curved surface as shown in FIG. 7 can also be detected. Since the probe can be installed arbitrarily according to the shape of the workpiece, it can also be used in production lines that handle a small amount of workpieces, and the drying characteristics of the coating applied to the workpiece can be obtained directly from the substitute sample it can.
In addition, the probe of the light source 1 and the light receiving unit 2 can be attached and detached, and various types of probes such as a reflection type, a transmission type, or a microscopic type that expands each can be attached depending on the measurement conditions and environment. The probe can be exchanged according to the shape and characteristics.

  Since the content of the material constituting the sample can be detected from the infrared absorption spectrum, it can be applied to the use of evaluating the drying characteristics of paints, adhesives and the like.

1 is a configuration diagram of a drying characteristic detection apparatus showing a first embodiment of the present invention. The flowchart which shows the drying characteristic detection process of 1st Example of this invention. Schematic diagram of infrared absorption spectrum showing the first embodiment of the present invention Schematic diagram of a calibration curve showing the relationship between solvent concentration and absorbance in the first embodiment of the present invention The graph showing the time change of the solvent content in 1st Example of this invention The block diagram of the drying characteristic detection apparatus which shows 2nd Example of this invention. Schematic diagram of a movable infrared probe of a drying characteristic detection apparatus showing a third embodiment of the present invention The graph which shows the time change of the weight decreasing rate from the initial weight of the conventional coating film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Infrared light source 2 Infrared light-receiving part 3 Infrared spectroscopy analyzer (Fourier transform type)
4 arithmetic device 5 storage device 6 display unit

Claims (3)

In the drying characteristic detection method for irradiating the film to be measured with electromagnetic waves, detecting the reflected electromagnetic waves and evaluating the drying characteristics of the film to be measured,
The electromagnetic wave is an infrared ray, a calibration curve of the infrared absorbance and solvent content of various solvents measured in advance is stored, and then the infrared absorbance of infrared rays reflected or transmitted from the coating film to be measured is measured. A method for detecting a drying characteristic, comprising: comparing the measured infrared absorbance with the stored calibration curve to calculate a solvent content in the coating film to be measured. Electromagnetic wave irradiation means for irradiating the film to be measured with electromagnetic waves, electromagnetic wave detection means for detecting electromagnetic waves reflected from the film to be measured, calculation means for calculating the detected electromagnetic wave characteristics, and display for displaying the calculation result A drying characteristic detecting device for evaluating the drying characteristic of the coating film to be measured.
The electromagnetic wave irradiation means is an infrared light source, and a storage device is provided for storing a calibration curve of the infrared absorbance and solvent content of various solvents measured in advance, and the electromagnetic wave detection means is reflected from the measured coating film as an infrared spectroscopic analyzer. The infrared absorbance of the transmitted infrared is measured, and the calculation means calculates the solvent content in the film to be measured by calculating and comparing the measured infrared absorbance with a calibration curve stored in the storage device. Drying characteristic detection device.   3. The drying characteristic detection apparatus according to claim 2, wherein the infrared spectroscopic analysis apparatus includes a movable transmission type or reflection type probe according to the shape of the coating film to be measured.

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