JPH0579826A - Method and apparatus for measuring coating weight of multilayered coating film - Google Patents

Abstract

PURPOSE:To measure the attached amounts of primer and paint which are applied to, e.g. a zinc-plated steel plate accurately and readily without destruction. CONSTITUTION:A sample to be measured 10 has a lower applied film (primer) 14 and an upper applied film (paint) 15 on a ground substrate of a zinc-plated steel plate 13 or the like. The upper applied film 15 of the sample 10 is measured with this method and apparatus. Radiation B1 is applied to the surface of the applied film 15. The intensity of Compton scattering rays Bc from the sample to be measured 10, which has received the radiation B1, the intensity of fluorescence X rays B2 of zinc and the intensity of fluorescence X-rays B3 of strontium from the lower applied film 14 are measured. The coating weight of the upper applied film 15 is operated based on the three measured intensities.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring an amount of a multi-layer coating film obtained by coating a plurality of coating films on a base substrate such as a galvanized steel plate.

[0002]

2. Description of the Related Art Generally, the constituent elements of a coating film such as paint are kept secret. Therefore, conventionally, a measurement method has been known in which a sample to be measured having a coating film on a base substrate is irradiated with radiation and the amount of the coating film attached is measured from the intensity of Compton scattered rays generated (for example, a special method). Kosho 63-1
9004, Japanese Patent Laid-Open No. 64-41810).

Since the Compton scattered rays are generated not only from the coating film but also from the base substrate, the strength of the Compton scattered radiation is, for example, that of the base substrate even if the amount of coating film adhered is constant as shown in FIG. 2 (a). If the amount of zinc plating is large, it will decrease. In addition, the intensity of Compton scattered rays varies depending on the type of plating, even if the amount of plating adhered is constant as shown in FIG. 2 (b). Therefore, in this type of measuring method, the amount of coating film adhered is obtained in consideration of the background component generated from the underlying substrate. For example, in the measuring method described in Japanese Patent Laid-Open No. 64-41810, the material of the underlying substrate is previously set.
The amount of coating film adhered is calculated from the intensity of Compton scattered rays using the calibration curve obtained according to (type).

[0004]

However, even if the material (type) of the underlying substrate is the same, the composition, that is, the component ratio of the elements, differs slightly depending on the lot or the like. In particular, when the base substrate is a plated steel sheet, uneven plating thickness is unavoidable, and the amount of plating adhered becomes uneven.
Therefore, if the coating amount of the coating film was obtained simply by using the calibration curve corresponding to the material (type) of the base substrate and the set coating amount of the plating (different from the actual coating amount), There is an error in the measured value due to unevenness in the amount of plating or the amount of plating.

As a countermeasure against this, the underlying substrate before coating is irradiated with radiation, the background component is obtained in advance from the generated fluorescent X-rays, and then the same position of the measured sample after coating is irradiated with radiation. A method is conceivable in which the intensity of the generated Compton scattered rays is obtained and the amount of the coating film attached is calculated from the intensity of the Compton scattered rays and the background component. However, it is inconvenient to set the same measurement position before and after painting, and it is difficult to make the measurement positions completely the same, so it is inevitable that a slight error will occur in the measured value. In particular, when the sample to be measured is continuously moving on the production line, it is necessary to track the data, but an error is likely to occur in the measured value due to changes in the moving speed of the sample to be measured.

Therefore, the applicant of the present invention measures the Compton scattered rays and the fluorescent X-rays from the underlying substrate from the sample to be measured after coating, and calculates the amount of coating film adhesion based on these intensities. He invented a method for measuring quantity and has already applied for it (see Japanese Patent Application No. 3-61155).

However, when the paint is applied to the galvanized steel sheet, the primer is applied to the galvanized steel sheet and then the paint is applied to the upper layer of the primer. In such a case, assuming that the amount of primer in the lower layer is constant, the amount of primer in the lower layer is subtracted from the amount of primer in the entire coating film to obtain the amount of paint in the upper layer. ..
However, it is inevitable that a slight error will occur in the amount of primer attached. On the other hand, the intensity of Compton scattered rays generated from the primer is as shown in Fig. 2 (c). However, the error in the amount of adhesion of the primer in the lower layer appears as a large error in the calculated value of the amount of paint in the upper layer. The present invention has been made to solve the above problems, and of course, not only the material of the base substrate and the type of plating are changed, but also the component ratio of the elements of the base substrate and the adhesion amount of the plating are uneven, or An object of the present invention is to provide a method and an apparatus for measuring the amount of adhesion of a multi-layer coating film, which can easily and accurately measure the amount of adhesion of the upper coating film even if the amount of adhesion of the lower coating film is uneven.

[0008]

In order to achieve the above object, the method of the present invention first comprises irradiating the surface of a coating film of a sample to be measured having a two-layer coating film on a base substrate with radiation, The intensity of Compton scattered rays, the intensity of fluorescent X-rays from the underlying substrate, and the intensity of fluorescent X-rays from the underlying coating film are measured from the sample to be measured that has received this radiation. The adhesion amount of the upper coating film is calculated based on the measured Compton scattered rays and the intensities of the two types of fluorescent X-rays. The apparatus of the present invention measures the intensity of Compton scattered radiation from a radiation source that irradiates the surface of the coating film of a sample to be measured having a two-layer coating film on a base substrate with radiation, and the sample to be measured that has received this radiation. And a first measuring device that outputs a first measurement signal,
A third measuring device that measures the fluorescent X-ray from the underlying substrate that receives the radiation and outputs the second measurement signal, and the fluorescent X-ray from the coating film of the lower layer that receives the radiation. And a third measuring device that outputs a signal. The calculator receives the first, second and third measurement signals, and calculates the amount of the upper coating film adhered based on the intensities of Compton scattered rays and two types of fluorescent X-rays.

[0009]

According to the present invention, the Compton scattered rays from the sample to be measured which have received the radiation and the intensity of the fluorescent X-rays from the underlying substrate and the lower coating film are measured, that is, the intensity of the Compton scattered rays. And the physical quantity corresponding to the intensity of the Compton scattered rays of the background component in the sample to be measured, so that the same position as the position where the Compton scattered rays are generated depends not only on the underlying substrate but also on the underlying coating film. The background component can be corrected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a sample 10 to be measured is a lower coating film on a base substrate 13 composed of a steel plate 11 and a zinc plating layer 12.
14 and the upper coating film 15. The upper coating film 15 is
The paint whose component elements are not known, while the lower coating film 14 is composed of a primer that improves the adhesion between the zinc plating layer 12 and the paint. The primer contains strontium and chromium in a substantially constant proportion. The sample 10 to be measured is, for example, continuously moving. An adhesion amount measuring device 20 is provided at an arbitrary position where the measured sample 10 is moving.

The adhesion amount measuring device 20 comprises a radiation source 21, first, second and third measuring devices 30, 40 and 50, a calculator 23,
And a display 24. The radiation source 21 is the measured sample 10
The surface of the upper coating film 15 is irradiated with the radiation B1. For example, an X-ray tube or a radioactive isotope of americium is used.

The first measuring device 30 comprises a parallel optical system 31, a first dispersive crystal 32, a first detector 33 and a first counting circuit section 34, and the Compton from the measured sample 10 which has received the radiation B1. The intensity of the scattered radiation Bc is measured. First dispersive crystal 32
Is the Compton scattered ray Bc scattered from the measured sample 10.
Is diffracted at a predetermined diffraction angle and is incident on the first detector 33. The first detector 33 detects the incident Compton scattered ray Bc and outputs it to the first counting circuit unit 34 as a detection output e1.
The first counting circuit section 34 counts the detection output e1 and calculates the intensity of the Compton scattered ray Bc as the first measurement signal c.
Output to 23.

The second measuring device 40 comprises a parallel optical system 41, a second dispersive crystal 42, a second detector 43 and a second counting circuit section 44. The second measuring device 40 measures the fluorescent X-ray B2 from the zinc plating layer 12 which has received the radiation B1, and in the case of this embodiment, measures the intensity of the fluorescent X-ray B2 of zinc. The sample 10 to be measured is excited by receiving the radiation B1 and emits a fluorescent X-ray. The second dispersive crystal is a fluorescent X-ray of zinc among fluorescent X-rays.
B2 is diffracted at a predetermined diffraction angle and is incident on the second detector 43. The second detector 43 detects the incident fluorescent X-ray B2 of zinc and outputs it as the detection output e2 to the second counting circuit unit 44.
The second counting circuit unit 44 counts the detection output e2 and outputs the intensity of the fluorescent X-ray B2 of zinc to the calculator 23 as the second measurement signal x2.

The third measuring device 50 has the same structure as the second measuring device 40, and includes a parallel optical system 51, a third dispersive crystal 52, a third detector 53 and a third counting circuit section 54. .. This third measuring device 50 is used for the coating film 14 of the lower primer which has received the radiation B1.
The fluorescent X-ray B3 from the above is measured. In this example, the intensity of the fluorescent X-ray B3 of strontium is measured. The third dispersive crystal 52 diffracts the fluorescent X-ray B3 of strontium among the fluorescent X-rays at a predetermined diffraction angle, and the third detector
Inject it into 53. The third detector 53 detects the incident fluorescent X-ray B3 of strontium and outputs it to the third counting circuit unit 54 as a detection output e3. The third counting circuit section 54 detects the detection output e3.
Is counted and the intensity of the fluorescent X-ray B3 of strontium is output to the calculator 23 as the third measurement signal x3.

The arithmetic unit 23 is provided with the three measurement signals c, x2, x3.
In response to this, based on the intensities of the Compton scattered rays Bc and the intensities of the two types of fluorescent X-rays B2 and B3, the adhesion amount of the upper coating film 15 is calculated as follows. Hereinafter, this calculation method will be described in detail.

[0016]

[Equation 1]

[0017]

[Equation 2]

[0018]

[Equation 3]

[0019]

[Equation 4]

[0020]

[Equation 5]

[0021]

[Equation 6]

[0022]

[Equation 7]

[0023]

[Equation 8]

[0024]

[Equation 9]

[0025]

[Equation 10]

As described above, the arithmetic unit 23 uses the constants A _{n to} C _n defined for each type of paint and each measuring device,
Intensities I _C and I of Compton scattered ray Bc and both fluorescent X-rays B2
Both coating films 1 by the measurement signals c, x2, x3 indicating _Zn , I _Sr.
The amount of adhesion of 4, 15 and the galvanized layer 12 is calculated. The calculator 23 outputs the calculated adhesion amounts to the display 24 as the adhesion amount signals w1, w2, w3. The display unit 24 displays and records the amount of adhesion of both coating films 14 and 15 and the galvanized layer 12.

Next, the operation of the above configuration will be described. When the radiation source 21 irradiates the surface of the upper coating film 15 of the sample 10 to be measured with the radiation source B1, the first measuring device 30 measures the intensity I _C of the Compton scattered ray Bc and the second
And the third measuring instruments 40 and 50 measure the intensities I _Zn and I _Sr of the fluorescent X-rays B2 and B3 of zinc and strontium, respectively. Subsequently, the arithmetic unit 23 is the above (21), (27), (28)
According to the formula, the amount of zinc coating W _Zn and the coating film 14 of the lower layer
Obtaining of a coating weight W _P of coating weight W _Pri and the upper coating film 15 calculates. As a result, it is possible to make a correction corresponding to the change in the background component caused by the uneven amount of the adhered amount of the primer and the plating.

Here, since the Compton scattered ray Bc and both fluorescent X-rays B2 and B3 are simultaneously measured from the sample 10 to be measured which has received the radiation B1 to correct the background component, tracking is not performed. However, the correction can be accurately performed. Therefore, even if there is unevenness in the amount of adhesion of the primer or zinc plating, the amount of the upper coating film 15, that is, the amount of paint, can be easily and accurately measured.

Further, since the amount of adhesion of both coating films 14 and 15 as well as the amount of adhesion of zinc coating layer 12 can be measured by one radiation source 21, the amount of adhesion of zinc plating can be measured before coating the primer. In addition, the structure is simpler than that of an apparatus in which the amount of primer attached is measured before painting of the paint and the amount of attached coating film 14 is measured after painting.

In the above embodiment, the case where the base substrate 13 is a galvanized steel sheet has been described, but the present invention can be applied to other galvanized steel sheets. Further, since the fluorescent X-rays of the elements such as Cr, Fe, and Ni can be measured to determine the component ratio of the elements, such as a stainless steel plate without a plating layer, the same can be applied.

In the above embodiment, the case where the two coating films 14 and 15 are provided on the base substrate 13 has been described.
The present invention can be applied even if the coating film has three or more layers. When the number of coating films is three or more, the intensity of fluorescent X-rays from each lower coating film excluding the uppermost coating film is measured, and Compton scattered rays, fluorescent X-rays from each lower layer and from the base substrate are measured. The adhesion amount of the upper coating film is calculated based on the measured value of the intensity of the fluorescent X-ray.

[0032]

As described above, according to the present invention, the Compton scattered radiation from the sample to be measured which has received the radiation and the intensity of the fluorescent X-ray from the underlying substrate and the coating film of the lower layer are measured. Since the intensity of Compton scattered rays and the physical quantity corresponding to the intensity of the Compton scattered rays of the background component in the sample to be measured are measured, it is possible to measure the physical quantity at the same location where the Compton scattered rays occur, Not to mention the change in the material of the base substrate and the type of plating, even if there is unevenness in the component ratio of the element of the base substrate or the amount of plating adhered, or if there is unevenness in the amount of coating film of the lower layer, It is possible to accurately measure the adhesion amount of the upper coating film. Moreover, since it is not necessary to set the measurement positions to be the same or perform tracking, it is possible to easily perform the measurement.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an adhesion amount measuring device showing an embodiment of the present invention.

[FIG. 2] (a) is a characteristic diagram showing a change in intensity of Compton scattered rays in a plated steel sheet, (b) is a characteristic diagram showing a change in intensity of Compton scattered rays due to a difference in material of a base substrate,
(c) is a characteristic diagram showing changes in the intensity of Compton scattered rays due to the difference in the material of the coating film.

[Explanation of symbols]

10 ... Sample to be measured, 13 ... Base substrate, 14 ... Lower coating film, 15
… Upper coating film, 20… Adhesion amount measuring device, 21… Radiation source,
23 ... Arithmetic unit, 30 ... First measuring instrument, 40 ... Second measuring instrument, 50 ... Third measuring instrument, B1 ... Radiation, B2 ... Fluorescent X-ray from base substrate,
B3 ... Fluorescent X-rays from the lower coating film, Bc ... Compton scattered rays, c ... First measurement signal, x2 ... Second measurement signal, x3 ... Third measurement signal.

[Procedure amendment]

[Submission date] May 22, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Front page continuation (71) Applicant 000006910 Yodogawa Steel Works, Ltd. 4-1-1 Minamihonmachi, Chuo-ku, Osaka-shi, Osaka (72) Inventor Naoki Matsuura 14-8 Akaoji-cho, Takatsuki-shi, Osaka Rigaku Denki Kogyo Incorporated (72) Inventor Seiya Shibata 14-8 Akaoji-cho, Takatsuki-shi, Osaka Prefecture Rigaku Denki Kogyo Co., Ltd. (72) Inventor Akira Tanaka, 2 Dejima Nishimachi, Sakai-shi, Osaka Prefecture Igeta Steel Plate Co., Ltd. (72 ) Inventor Shigeo Fukuda 8252-11 Tamashima Otoshima, Kurashiki City, Okayama Prefecture In Kawatetsu Steel Plate Co., Ltd. (72) Hiroki Nishiyama 883 Kanesugi Town, Funabashi City, Chiba Taiyo Steel Kinsugi House 2-231 (72) Inventor Mitsuru Tanaka Osaka 4-1-1 Minamihonmachi, Chuo-ku, Osaka-shi, Japan Inside the Yodogawa Steel Works

Claims (2)

[Claims] 1. A surface of a coating film of a sample to be measured, which has coating films of a lower layer and an upper layer on a base substrate, is irradiated with radiation,
The intensity of Compton scattered rays, the intensity of fluorescent X-rays from the base substrate, and the intensity of fluorescent X-rays from the lower coating film were measured from the sample to be measured that received this radiation, and these measurements were performed. Compton scattered radiation and the above two types of fluorescence X
A method for measuring the adhesion amount of a multi-layer coating film, which calculates the adhesion amount of the upper coating film based on the strength of the line. 2. A radiation source for irradiating the surface of the coating film of the sample to be measured having the lower and upper coating films on the underlying substrate with radiation, and the intensity of Compton scattered radiation from the sample to be measured which has received this radiation. A first measuring device that measures and outputs a first measuring signal, a second measuring device that measures the fluorescent X-ray from the underlying substrate that has received the radiation and outputs a second measuring signal, and the radiation A third measuring device that measures the fluorescent X-rays from the lower coating film and outputs a third measuring signal, and receives the first, second and third measuring signals to receive the Compton scattered rays and the above-mentioned A multi-layer coating film adhesion amount measuring device comprising a calculator for calculating the adhesion amount of the upper layer coating film based on the intensities of two types of fluorescent X-rays.