JPH0650816A - Estimation of color of dried coating film of colored liquid - Google Patents

Abstract

PURPOSE:To predict the color of a dried coating film speedily from the data on a colored liquid solution state by measuring the reflectivity of the colored liquid and that of dried coating film within a specific wavelength region and using equations standing approximately for both. CONSTITUTION:In a specific wavelength region of 380 to 700nm usually used for color imetry, the reflectivity Rw(lambdai) of a colored liquid and reflectivity RD(lambdai) of its dried coating film are measured for a wavelength lambdai. By using either of equations I to III approximately standing in a region for both, the reflectivity RD(lambdai) of the dried coating film is calculated with the reflectivity R (lambdai) of a colored liquid similar in color system to the colored liquid, and the color of the dried coating film of the colored liquid is estimated. Where, alphai, betai indicate the coefficients when alpha, beta depend on the wavelength lambdai. By this method, the color of coating film after drying is accurately and speedily estimated and thus, color control of colored liquids can be done speedily and easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for estimating a dry coating film color of a colored liquid used in a paint manufacturing process, etc. The present invention relates to a method for estimating a dry coating film color of a colored liquid capable of accurately and quickly estimating the coating film color, and quickly and easily adjusting the coloring liquid.

[0002]

2. Description of the Related Art Conventionally, color control in a color-adjusting process of a coloring solution such as paint, ink and plastic has been carried out by forming the above-mentioned coloring solution into a coating film and measuring the color in a dry state. That is, a method of forming a colored solution into a coating film, calculating the compounding ratio of the colorant from the difference between the color measured after the drying step and the measured color of the target coating film, changing the toning conditions, etc. It was taken.

Another method has been attempted, in which a coloring solution such as paint, ink or plastic is sampled in a color measurement cell to measure the color, and the color is adjusted in the solution state. A method for measuring the color of such a coloring solution is described in JP-B-61-50229.
JP, JP 61-56923, JP 61-
Japanese Patent No. 65123 discloses a method of immersing an optical fiber in a coloring solution for measurement. Further, Japanese Patent Application Laid-Open No. 60-174932 discloses a computer color matching method for predicting a color at an arbitrary density by using the spectral reflectance of a colored material having a specific colorant formulation.

[0004]

However, by measuring the color of a dried coating film of a coloring solution such as paint, ink and plastic,
From the difference between the colorimetry of the target coating film, in the method of calculating the blending ratio of the colorant, the time to dry the coating film is essential,
There is a problem that the response time required to change the toning condition becomes long. Further, in the method of measuring the color in a solution state using the above optical fiber, the coloring component adheres to the glass of the color measurement cell and it is difficult to completely remove it, and the color itself is discolored by the attached coloring component. Then, there was a problem that correct color measurement could not be performed. Furthermore, this method has the problem that the target standard must be a liquid in order to make a better measurement, and this standard liquid does not match the true target color of the dry coating, and this The method requires a device for wiping the detection probe and may damage the probe tip when repeatedly wiping. Further, the above-described method of predicting the coloring result is based on the premise of dyeing the fiber, and cannot be immediately applied to the colorimetric toning of a coloring solution such as paint, ink and plastic.

Therefore, the present invention solves the above problems,
It does not need time to dry the coating film of paint, ink, plastic, and other coloring solutions, and it is possible to avoid erroneous measurement due to adhesion of coloring agent at the tip of the detection probe. It is intended to provide a method for estimating a dry coating film color accurately and quickly.

[0006]

According to the present invention, the reflectance R of a colored liquid at a wavelength λ _i within a predetermined wavelength range is determined.
_w (λ _i ) and the reflectance R of the dried coating film of the colored liquid
_D (λ _i ) is measured, and both are approximately expressed by the following formula (1) to
Within the range in which any of (3) is satisfied, the reflectance of the dried coating film is calculated from the reflectance R _w (λ _i ) of the colored liquid of the same color as the colored liquid by using any one of the above expressions. R
It is a method for estimating a dry coating film color of a colored liquid, which is characterized by obtaining _D (λ _i ). _{R D (λ i) = α} i R w (λ i) + β i ··· (1) R D (λ i) = αR w (λ i) + β i ··· (2) R D (λ i) = Α _i R _w (λ _i ) + β (3) (where α _i and β _i are coefficients when the coefficients α and β depend on the wavelength λ _i .)

[0007]

In the present invention, a coloring liquid of a similar color to the coloring liquid whose dry coating color is to be estimated in advance, preferably a coloring liquid made of the same raw material, is used for colorimetry within a predetermined wavelength range. Within the range of 380 to 700 nm, the reflectance R _w (λ _i ) is measured while changing the wavelength λ _i , and similarly the reflectance R _D (λ _i ) of the dried coating film is obtained. The reflectance R _D (λ _i ) of the dried coating film is also preferably measured by directly applying the liquid colorimeter used in the present invention.

When there is no reaction that changes the hue (such as a change in the characteristics of the coloring group of the coloring material) during the drying process, the difference between the liquid color and the dry color is considered to be the difference in gloss. Then, in the actual color change data of the paint, L (lightness) and ((a) + (b))
^The above reasoning is supported by the fact that ^1/2 (saturation) changes greatly and (a / b) (hue) does not change much. That is, between the reflectance R _w (λ _i ) in the liquid state and the reflectance R _D (λ _i ) of the dry coating film, there is approximately a linear relationship like the following equations (1) to (3). To establish. _{R D (λ i) = α} i R w (λ i) + β i ··· (1) R D (λ i) = αR w (λ i) + β i ··· (2) R D (λ i) = Α _i R _w (λ _i ) + β (3) where α _i and β _i are coefficients representing a linear function of R _w (λ _i ) and R _D (λ _i ), and It depends on the wavelength λ _i . However, even if it is assumed that either α _i or β _i does not depend on λ _i , the linear function may be approximately satisfied, and equation (2) or equation (3) shows these cases. .

In order to estimate the dry coating color from the liquid color, it is preferable to actually measure the liquid color and the dry coating color for a sample group having the same main component such as a coloring material and different toning conditions, and to set the two sets. From the above data, the coefficient α or α _{i of} the equations (1) to (3),
Calculate β or β _i . Ideally, R _w (λ _i ) and R _D
If (λ _i ) is in a linear relationship, equations (1) to (3) are two-dimensional simultaneous linear equations, and therefore the coefficient α or α _i , β or β _i can be calculated with two sets of samples. it can. actually,
Considering experimental error, unknown disturbance, etc., many corresponding R
_It is preferable to determine the coefficient α or α _i , β or β _i from the _w (λ _i ) and R _D (λ _i ) values by using the method of least squares / correlation analysis. A regression curve is calculated for many data groups having a correlation coefficient of 0.8 or more to obtain the above coefficient at the wavelength λ _i . Usually such a measurement is performed, for example, with λ ₁ =
16 every 20 nm from 380 nm to λ ₁₆ = 700 nm
This is performed for each wavelength to obtain α _{1 to} α ₁₆ and β _{1 to} β ₁₆ .
By obtaining these, the reflectances R _w (λ ₁ ) to R of the colored solution sample obtained in the toning step of the paint of the same color system
_w (λ ₁₆ ) is measured and the dry coating film color R _D (λ ₁ ) to R _D
It is intended to estimate (λ ₁₆ ).

[0010]

Embodiments of the method for estimating the dry coating color of a colored liquid according to the present invention will be described in detail below with reference to the accompanying drawings. The present invention is not limited to these examples. FIG. 1 is a conceptual diagram of a liquid colorimetric apparatus used in the present invention. The measurement head 11 has the laser displacement meter head 1, the irradiation unit 12, and the light receiving unit 9 supported by an optical housing 10, and a detachable attachment 14 is provided at the lower end of the optical housing 10. The measuring head 11 is supported by the upright main shaft 7 via the measuring head support portion 8 and is moved up and down by the servo control device 6. The laser displacement meter head 1 is attached to a side portion of the optical housing 10 by a connecting portion 13, and the laser displacement meter 2 and the controller 4 are connected by a connection 3 and the controller 4 and the servo controller 6 are connected by a connection 5. Also,
The color sensor 19 is connected to the optical fiber 17 for guiding the standard light to the irradiation unit 12, and is connected to the optical fiber 18 for guiding the reflected light received by the light receiving unit 9 to the color sensor 19. Has been done. A coloring solution 16 such as paint, ink, or plastic, which is the object of color measurement, is contained in a coloring solution container 15 having a matte black bottom. In the case of paint, the depth of the coloring solution may be 10 mm or more.

The standard light is emitted from the irradiation section 12 at an angle of 45 degrees with respect to the normal line of the surface of the coloring solution 16, and among the light diffusely reflected by the surface, the angle with the normal line is 10 degrees. The reflected light within a degree is received by the light receiving unit 9. Then, the color measurement in the color sensor 19 is performed by measuring the common standard white surface and replacing the sample with the common white surface for comparative measurement.
A wavelength of 380 to 700 nm is irradiated from the irradiation unit 12 of the standard light source at intervals of 20 nm, and colorimetric evaluation is performed based on the distribution of the reflectance with respect to the common white surface.

Next, the color measurement procedure will be described. The laser displacement meter head 1 emits a laser having a wavelength of 670 nm from a semiconductor laser and receives the laser beam reflected by the surface layer of the coloring solution 16 again. The laser displacement meter 2 calculates the distance between the laser displacement meter head 1, that is, the measuring head 11 and the surface of the coloring solution 16 based on the displacement signal measured by the laser displacement meter head 1, and sends the signal to the controller 4. The servo unit 6 is fed back to drive the irradiation unit 12, the light receiving unit 9,
The position of the measuring head 11, which is integrated with the optical housing 10, is vertically controlled along the axial direction of the upright main shaft 7. Although the liquid level of the coloring solution 16 changes due to the liquid dripping from the inner wall surface of the coloring solution container 15, the measuring head 11 is moved in the up-and-down direction by the above position control, and the focus position of the light receiving unit 9 is moved up and down. It can be adapted to the surface of the colored solution 16 that has changed direction. When the measuring distance between the measuring head 11 and the surface of the colored solution 16 is set to about 10 mm, even if the colored solution has a high viscosity, the focusing control can be satisfactorily performed even when the adhering liquid drops from the wall surface. Further, when the attachment hood 14 is controlled within a range of about 2 to 3 mm above the surface of the coloring solution 16, flare light from above the measuring head 11 can be cut, and good focusing control and high accuracy can be achieved. Colorimetric control is possible. As a result, the reproducibility accuracy of color difference can be set to 0.1 or less. The attachment hood 14 is usually detachably attached to the edge of the optical housing 10.
It is also possible to extend the edges of the to achieve the same effect.

(Reference Example) Using the colorimetric apparatus of FIG. 1, paint A
The coating B and the coating B were repeatedly measured at room temperature to examine the variation in the measured values. The color sensor is JUKI's JP71
A 00 type spectrocolorimeter was used, and a laser displacement meter was LC-2320 manufactured by Keyence Corporation. The standard light source C was used for the irradiation light, the wavelength 380 to 700 nm was measured at intervals of 20 nm, and the lightness L and the hue a and b values were obtained. And L,
The differences in the differences ΔL, Δa, and Δb between the average values of a and b and the respective measured values were obtained, and the differences in color difference were calculated. The measurement was performed by sampling the paint toned in advance in a petri dish made of aluminum wheels and setting the position of the petri dish. After the second time, the paint in the petri dish was thoroughly stirred with a stir bar, and the process from the position setting of the petri dish to the color measurement was repeated again. The number of repetitions is 30 times. The measurement results such as variations in color difference (ΔE) are shown in Table 1 for the paint A and Table 2 for the paint B. As is clear from each table,
It was confirmed that the average value (reproducibility) of the color difference between the paints A and B by repeated colorimetry was below the target value of 0.1.

[0014]

[Table 1]

[0015]

[Table 2]

(Examples 1 and 2) With respect to the toned coating material C, the liquid color was repeatedly measured 10 times in the same manner as in Reference Example. As the dry coating film color, a paper piece sample obtained by applying the above-mentioned coating material C to a paper piece and drying it was used, and the same color as the liquid color was used.
Measured twice. The results are shown in Table 3. The numerical values show the average of the measured values.

[0017]

[Table 3]

Next, assuming that the above equations (2) and (3) are established, 20n in the wavelength range of 380 to 700 nm.
Reflectance of paint and dry paper piece for each m R _w (λ _i ) R
_D (λ _i ) is obtained, and α, β _{i and} α _i ,
β was calculated. The obtained relational expressions, the estimated dry colors (L, a, b) from them, and the color difference (ΔE) between the measured dry colors and the estimated dry colors are shown in Tables 4 and 5.

[0019]

[Table 4]

[0020]

[Table 5]

Similarly, with respect to the paint D toned in the same manner, the formulas shown in Tables 4 and 5 obtained for the paint C were directly applied to estimate the dry color. The results are as shown in Tables 6 and 7. From the results of Tables 4 to 7, it was found that the dry coating film color estimation method of the present invention can estimate the dry coating film color with high accuracy from the color measurement result of the paint.

[0022]

[Table 6]

[0023]

[Table 7]

[0024]

According to the present invention, by adopting the above-mentioned constitution, in the production of a coloring solution such as paint, ink and plastic, and in the color-adjusting process, the color measurement can be efficiently performed without contact with the coloring solution. From this, it became possible to estimate the dry coating film color with high accuracy. As a result, it becomes possible to immediately feed back the estimated dry coating film color in the toning process of paints, etc., and it is possible to avoid the complexity involved in color measurement such as conventional coating film drying. It has made it possible to significantly shorten the solution manufacturing process.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a color measurement device that is an embodiment of the present invention.

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[Procedure amendment]

[Submission date] August 21, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

[Table 1]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015]

[Table 2]

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

[0023]

[Table 7]

[Procedure amendment]

[Submission date] January 12, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

[Table 1]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015]

[Table 2]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirotoshi Horizoe 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Inventor Hiroshi Sato 1382 Shimoishi, Otawara, Tochigi Prefecture ─ 12 Dainippon Paint Co., Ltd. (72) Inventor Kaoru Yoshida 6-1-12, Nishikujo, Konohana Ward, Osaka City, Osaka Prefecture Dainippon Paint Co., Ltd.

Claims (1)

[Claims] 1. A reflectance R _w (λ _i ) of a colored liquid and a reflectance R _D (λ _i ) of a dried coating film of the colored liquid at a wavelength λ _i within a predetermined wavelength range are measured, and both are approximated. The reflectance R _w (λ _i ) of the colored liquid of the same color as the colored liquid is calculated by using any one of the above expressions within a range in which any of the following expressions (1) to (3) is satisfied. A method for estimating the dry coating film color of a colored liquid, characterized in that the reflectance R _D (λ _i ) of the dry coating film is obtained from the above. _{R D (λ i) = α} i R w (λ i) + β i ··· (1) R D (λ i) = αR w (λ i) + β i ··· (2) R D (λ i) = Α _i R _w (λ _i ) + β (3) (where α _i and β _i are coefficients when the coefficients α and β depend on the wavelength λ _i .)