Method for predicting dry paint color values from liquid paint color values

Abstract

The present invention relates to a method for predicting a dry paint color value from a liquid paint color value, in which a process for preparing a second dry paint film by drying and curing the second liquid paint film is omitted when preparing a second liquid paint film having the same composition as a first liquid paint film, and the reflectivity of the second dry paint film can be predicted according to the prediction method of the present invention.

Description

Technical Field

[0001] The present invention relates to a method for predicting the color value of dry paint from the color value of liquid paint. Background Art

[0002] The preparation process of the coating usually includes the steps of adding the coating components and mixing them according to the required process, and detecting the target color value before the final step. For example, the raw materials required for the preparation of the coating are injected, and the color is adjusted by dispersion and dissolution after mixing, and then the preparation process is finally completed by the color detection step. Among them, the color detection step includes a dry film formation step of taking out a small amount of liquid coating in preparation to dry the coating film. Usually, after the spraying process of the liquid coating or the coating process of brush, roller and scraper (bar coater), the drying / curing process of the coating according to the curing conditions is added.

[0003] In the paint preparation process, color verification involves the steps of liquid paint sample collection, coating film formation, and drying / curing. The execution process takes at least 1 hour to several hours, thus delaying the preparation process. The use of the collected samples may result in the generation of waste paint and the resulting environmental problems.

[0004] In addition, in the case of coatings prepared with the same ingredients, the color values ​​of the liquid coating and the dry coating prepared therefrom may differ depending on the preparation environment, such as the mixing environment, the drying and curing environment, etc. Therefore, when it is desired to prepare the same liquid coating and the dry coating prepared therefrom, there is a problem that the color values ​​of the liquid coating and the dry coating prepared therefrom as the final product may differ even when the same ingredients are input.

[0005] Therefore, it is necessary to replace the dry paint color verification process including the drying / curing process after the spraying process or the painting process of brush, roller and scraper (bar coater) with a liquid paint color verification process performed in the liquid paint state. Moreover, it is necessary to standardize the changes in the prepared liquid paint color value and the dry paint color value and derive them by an algorithm, and then only the liquid paint color value is used to predict the dry paint color value in the same paint preparation process.

[0006] [Prior art literature]

[0007] (Patent Document 1) Korean Patent No. 10-2191784 (December 10, 2020)

[0008] (Patent Document 2) Korean Patent No. 10-1985-0006893 (October 21, 1985)

[0009] (Non-patent document 1) Prediction of paint pigment mixing ratio for reproducing target color, J. of the Korean Oil Chemists' Soc, Vol. 25, No. 4. December, 2008. 438-445 Summary of the invention

[0010] Technical issues

[0011] The present invention aims to provide a method for predicting the color value of dry paint from the color value of liquid paint. In the paint preparation process, the dry paint color verification step is replaced by the liquid paint color verification step, thereby simplifying the preparation process and reducing the generation of waste paint, thereby solving environmental problems.

[0012] Solution to the problem

[0013] In one embodiment, the present invention can provide a method for predicting the color value of a dry coating from the color value of a liquid coating, comprising: step a), preparing first to n-th first liquid coatings of the same composition; step b), measuring the liquid reflectivity of the first to n-th first liquid coatings at a wavelength r, respectively. 1st R wet Step c), drying and curing the first liquid coatings from the first time to the nth time to prepare the first dried coatings from the first time to the nth time; Step d), measuring the dry reflectivity of the first dried coatings from the first time to the nth time at a wavelength r 1st R Dry Step e), by the following formula, the weighted (Weight) value and the bias (Bias) value for the first liquid coating at wavelength r are obtained,

[0014] Among them, when When R T is the transposed matrix of matrix R, R -1 represents the inverse matrix of the matrix R; step f), preparing a second liquid coating having the same composition as the first liquid coating; step g), measuring the liquid reflectivity of the second liquid coating at a wavelength r 2nd R wet ; and step h), in the following formula, the weighted value and bias value of step e) and step g) are applied 2nd R wet , and thus the dry reflectance of the second dry coating film at wavelength r is obtained 2nd R Dry ,

[0015] Effects of the Invention

[0016] According to a method for predicting dry paint color values ​​from liquid paint color values ​​of the present invention, the color verification step of the dry paint is omitted, the dry paint color values ​​are predicted from the liquid paint color values, the preparation process is simplified and the generation of waste paint is reduced, thereby solving environmental problems. DETAILED DESCRIPTION

[0017] Hereinafter, the present invention will be described in detail with reference to Examples.

[0018] Korean Patent No. 10-2191784 (hereinafter referred to as "Patent Document 1") discloses an electroplating coating system having a liquid coating detection kit and a colorimeter for measuring the color of the liquid coating through a perspective window. However, Patent Document 1 only measures the color of the liquid coating and does not disclose or imply the content of predicting the color of the dry coating based on this.

[0019] The present invention provides a method for predicting the color value of dry paint from the color value of liquid paint.

[0020] According to the present invention, a first liquid coating film and a first dry coating film dried and cured therefrom are prepared. For the prepared first liquid coating film and the first dry coating film, the reflectivity at wavelength r is measured. The reflectivity of the measured first liquid coating film and the first dry coating film is applied to the formula according to the present invention, thereby obtaining a weighted (Weight) value and a bias (Bias) value applicable to the relationship between the reflectivity of the liquid coating film and the reflectivity of the dry coating film.

[0021] Afterwards, a second liquid coating film with the same composition as the first liquid coating film is prepared, and the reflectance of the first liquid coating film and the first dry coating film are applied to obtain a weighted value and a bias value, and the reflectance of the second dry coating film can be predicted using the weighted value and the bias value.

[0022] Therefore, according to the method for predicting the color value of dry coating from the color value of liquid coating of the present invention, when preparing a second liquid coating with the same composition as the first liquid coating, the process of drying and curing the second liquid coating to prepare the second dry coating is omitted, and the reflectivity of the second dry coating can be predicted according to the prediction method of the present invention.

[0023] The method for predicting the color value of dry coating from the color value of liquid coating according to the present invention may include: step a), preparing first to n-th first liquid coating films of the same composition; step b), measuring the liquid reflectivity of the first to n-th first liquid coating films at a wavelength r, respectively. 1st R wetStep c), drying and curing the first liquid coatings from the first time to the nth time to prepare the first dried coatings from the first time to the nth time; Step d), measuring the dry reflectivity of the first dried coatings from the first time to the nth time at a wavelength r 1st R Dry Step e), by the following formula, the weighted (Weight) value and the bias (Bias) value for the first liquid coating at wavelength r are obtained,

[0024] Among them, when When R T is the transposed matrix of matrix R, R -1 represents the inverse matrix of the matrix R; step f), preparing a second liquid coating having the same composition as the first liquid coating; step g), measuring the liquid reflectivity of the second liquid coating at a wavelength r 2nd R wet ; and step h), in the following formula, the weighted value and bias value of step e) and step g) are applied 2nd R wet , and thus the dry reflectance of the second dry coating film at wavelength r is obtained 2nd R Dry ,

[0025] In the present invention, the relationship between a liquid coating film at a wavelength r (nm) and a dry coating film dried and cured therefrom can be shown by the following Mathematical Formula 1.

[0026] [Mathematical formula 1]

[0027]

[0028] in,

[0029] is the reflectance (%) of the dry coating film at wavelength r (nm),

[0030] is the reflectivity (%) of the liquid coating at wavelength r (nm),

[0031] Weight r is the weighted value,

[0032] Bias r Indicates the bias voltage value.

[0033] Therefore, when liquid coating films of the same composition are prepared n times and the respective liquid coating films are dried and cured to prepare dry coating films, the relationship between the liquid coating films and the dry coating films can be expressed by the following Mathematical Formula 2.

[0034] [Mathematical formula 2]

[0035]

[0036] in,

[0037] is the reflectance (%) of the dried coating film prepared for the nth time at wavelength r (nm),

[0038] is the reflectivity (%) of the liquid coating prepared for the nth time at wavelength r (nm),

[0039] Weight r is the weighted value,

[0040] Bias r Indicates the bias voltage value.

[0041] If the above-mentioned Mathematical Formula 2 is expressed as a determinant for each of the liquid coating film and the dried coating film prepared for the first to nth times using the same components, it can be expressed as the following Mathematical Formula 3.

[0042] [Mathematical formula 3]

[0043]

[0044] in,

[0045] is the reflectance (%) of the first prepared dry coating film at wavelength r (nm),

[0046] is the reflectance (%) of the dried coating film prepared for the nth time at wavelength r (nm),

[0047] is the reflectivity (%) of the first prepared liquid coating at wavelength r (nm),

[0048] is the reflectivity (%) of the liquid coating prepared for the nth time at wavelength r (nm),

[0049] Weight r is the weighted value,

[0050] Bias r Indicates the bias voltage value.

[0051] Regarding equation 3, the least square method can be used to calculate the Weight at wavelength r (nm) using equation 4 below: r and Bias r .

[0052] [Formula 4]

[0053]

[0054] in,

[0055] when hour,

[0056] R T is the transposed matrix of matrix R,

[0057] R -1 Represents the inverse matrix of matrix R.

[0058] Therefore, for the first liquid coating film prepared for the first to nth times with the same composition and the first dry coating film prepared therefrom, the reflectance is measured at a wavelength r (nm), and the measured reflectance is applied to Mathematical Formula 4, so that the weighted (Weight) value and the bias (Bias) value can be calculated at the wavelength r (nm).

[0059] Then, a second liquid coating film having the same composition as the first liquid coating film is prepared, and the reflectance of the second liquid coating film is measured at a wavelength r (nm). The measured reflectance is applied to Mathematical Formula 2 to obtain the reflectance of the second dried coating film.

[0060] In addition, from the reflectance of the second dried coating film obtained by Mathematical Formula 2, the color values ​​CIE L*, a*, and b* of the second dried coating film can be obtained.

[0061] The method of obtaining color values ​​CIE L*, a*, and b* from reflectance is known, and is disclosed in, for example, "Prediction of paint pigment mixing ratio for reproducing target color, J. of the Korean Oil Chemists' Soc, Vol. 25, No. 4. December, 2008. 438-445 (Non-Patent Document 1)".

[0062] For example, in the XYZ colorimetric system, the tristimulus values ​​XYZ of the color of the reflected object can be obtained by the following equation at a wavelength of 380 nm to 780 nm.

[0063]

[0064] in,

[0065] S(λ) is the spectral distribution of standard light used to display color, is the color-matching function in the XYZ color system, and R(λ) is the reflectivity at the incident angle of the spectral beam.

[0066] In addition, using the tristimulus values ​​XYZ, CIE L can be calculated as follows, for example ＊ 、a ＊ , b ＊ Table color system.

[0067] L * =116(Y / / Y n ) 1 / 3 -16

[0068] a * =500[(X / X n ) 1 / 3 -(Y / Y n ) 1 / 3 ]

[0069] Y / Y n >0.008856

[0070] b * =200[(Y / Y n ) 1 / 3 -(Z / Z n ) 1 / 3 ]

[0071] L * =903.29(Y / Y n )

[0072] a * =500×7.787[(X / X n )-(Y / Y n )]

[0073] Y / Y n ≤0.008856

[0074] b * =200×7.787[(Y / Y n )-(Z / Z n )]

[0075] Among them, X n , Y n , Z n It is the tristimulus value of standard light.

[0076] Next, embodiments of the present invention will be described.

[0077] Example

[0078] Example 1: Product Name FU2300-LGREY

[0079] For the product name FU2300-LGREY, the first to tenth first liquid coatings were prepared. Specifically, the first to tenth first liquid coatings were prepared with the same ingredients used in the preparation of the product name FU2300-LGREY. The prepared first to tenth first liquid coatings were applied to the cover test paper at a thickness of 25 μm, respectively, to prepare the first to tenth first liquid coatings. For each prepared first liquid coating, within one minute, the color was measured at a wavelength of 400nm to 700nm at intervals of 10nm using a non-contact colorimeter X RITE VS450 or VS3200, so that the reflectivity was measured at a wavelength of 400nm to 700nm for each first liquid coating at intervals of 10nm.

[0080] In addition, for the first to tenth first liquid coatings prepared, a diluent (TH0254 (N)) was added according to the coating viscosity to adjust the viscosity (coating viscosity: 25°C, Ford cup No. 4 26 to 28 seconds (sec)). Then, the first liquid coating was applied to the electroplated 90x200mm CR steel plate 2-3 times by a sprayer, and the first liquid coating was applied to a thickness of 35±3μm, and after being placed at room temperature (10 to 30°C) for 5 to 10 minutes (min), it was cured at 150°C for 30 minutes (min). Then, the color was measured at a wavelength of 400nm to 700nm with a colorimeter X RITE I7 or CI7800 at a 10nm interval, so that the reflectivity was measured at a wavelength of 400nm to 700nm for each first dried coating film at a 10nm interval.

[0081] From the measured reflectance of the first liquid coating and the reflectance of the first dry coating, a weighted (Weight) value and a bias (Bias) value at a wavelength of 400nm to 700nm at a 10nm interval are obtained.

[0082] Examples 2 to 5

[0083] For the product names FU2300-WHITE PEARL BASE (D) (Example 2), FU2300-DGREY (Example 3), FU2300-Shiny Silver (Example 4), and FU2300-Nocturne Gray (Example 5), the process of Example 1 is performed to determine the weighted (Weight) value and bias (Bias) value at each wavelength.

[0084] The weighted (Weight) value and the bias (Bias) value at each wavelength are shown in Tables 1 to 3 below.

[0085]

Table 1

[0086]

[0087]

[0088]

Table 2

[0089]

[0090]

Table 3

[0091]

[0092] Test example: Comparison of errors of prepared coating films

[0093] For L*, a*, b* of Examples 1 to 5, the predicted values ​​and the measured values ​​were compared and the error values ​​are shown in Table 4 below.

[0094]

Table 4

[0095]

[0096]

[0097] As shown in Table 4, according to the method for predicting the color value of dry coating from the color value of liquid coating of the present invention, the color difference range of CIE L*, a*, b* of the predicted value and the measured value of the second dry coating film can be 0.5 or less or 0.4 or less. 2nd R Dry The color difference (ΔE*) between the predicted values ​​of CIE L*, a*, and b* of the second dried coating film and the measured values ​​of CIE L*, a*, and b* of the second dried coating film prepared by drying and curing may be 0.5 or less or 0.4 or less.

[0098] Hereinafter, various embodiments of the present invention will be described in detail.

[0099] (1) A method for predicting the color value of a dry coating from the color value of a liquid coating, comprising: step a), preparing first to n-th first liquid coating films of the same composition; step b), measuring the liquid reflectivity of the first to n-th first liquid coating films at a wavelength r, respectively. 1st R wet Step c), drying and curing the first liquid coatings from the first time to the nth time to prepare the first dried coatings from the first time to the nth time; Step d), measuring the dry reflectivity of the first dried coatings from the first time to the nth time at a wavelength r 1st R DryStep e), by the following formula, the weighted (Weight) value and the bias (Bias) value for the first liquid coating at wavelength r are obtained,

[0100] Among them, when When R T is the transposed matrix of matrix R, R -1 represents the inverse matrix of the matrix R; step f), preparing a second liquid coating having the same composition as the first liquid coating; step g), measuring the liquid reflectivity of the second liquid coating at a wavelength r 2nd R wet ; and step h), in the following formula, the weighted value and bias value of step e) and step g) are applied 2nd R wet , and thus the dry reflectance of the second dry coating film at wavelength r is obtained 2nd R Dry ,

[0101] (2) A method for predicting the color value of a dry coating from the color value of a liquid coating, wherein step a) comprises: the steps of respectively preparing first to n-th first liquid coatings made of the same ingredients, wherein n is an integer greater than 2; and the steps of respectively applying the first to n-th first liquid coatings to a coated object to prepare first to n-th first liquid coating films.

[0102] (3) A method for predicting the color value of a dry coating from the color value of a liquid coating, wherein step f) comprises: a step of preparing a second liquid coating having the same composition as the first liquid coating; and a step of applying the second liquid coating to a coated object to thereby prepare a second liquid coating film.

[0103] (4) A method for predicting the color value of a dry coating from the color value of a liquid coating, wherein the method further comprises step i) of predicting the color value of a dry coating from the dry reflectance of step h) 2nd R Dry The predicted values ​​of CIE L*, a*, and b* of the second dried coating film were determined.

[0104] (5) A method for predicting the color value of a dry coating from the color value of a liquid coating, characterized in that the dry reflectivity 2nd R Dry The color difference (ΔE*) between the predicted values ​​of CIE L*, a*, and b* of the second dried coating film and the measured values ​​of CIE L*, a*, and b* of the second dried coating film is 0.5 or less.

Claims

1. A method for predicting the color value of a dry coating from the color value of a liquid coating, wherein: include: Step a), preparing first to nth first liquid coating films of the same composition; Step b), at wavelength r, for the first liquid coating from the first time to the nth time, respectively measure the liquid reflectivity 1st R wet ; Step c), drying and curing the first to n-th first liquid coatings respectively to prepare the first to n-th first dried coatings; Step d), at wavelength r, for the first dried coating film from the first time to the nth time, respectively measure the dry reflectivity 1st R Dry ; Step e), using the following formula, the weighted (Weight) value and the bias (Bias) value for the first liquid coating at wavelength r are obtained: in, when hour, R T is the transposed matrix of matrix R, R -1 Represents the inverse matrix of matrix R (Inverse Matrix); Step f), preparing a second liquid coating film having the same composition as the first liquid coating film; Step g), measuring the liquid reflectivity of the second liquid coating at a wavelength r 2nd R wet ;and Step h), apply the weighted value and bias value of step e) and the value of step g) to the following formula: 2nd R wet , and thus the dry reflectance of the second dry coating film at wavelength r is obtained 2nd R Dry :

2. The method for predicting the color value of dry paint from the color value of liquid paint according to claim 1, wherein: Step a) comprises: The steps of respectively preparing the first to nth first liquid coatings made of the same ingredients, wherein n is an integer greater than 2; and The step of applying the first to n-th first liquid coatings to the coating object respectively, thereby preparing the first to n-th first liquid coating films.

3. The method for predicting the color value of dry paint from the color value of liquid paint according to claim 2, wherein: Step f) comprises: The step of preparing a second liquid coating having the same composition as the first liquid coating; and The step of applying the second liquid coating to the object to be coated to prepare a second liquid coating film.

4. The method for predicting the color value of dry paint from the color value of liquid paint according to any one of claims 1 to 3, wherein: The dry reflectance of step h) is further comprised of step i) 2nd R Dry The predicted values ​​of CIE L*, a*, and b* of the second dried coating film were determined.

5. The method for predicting the color value of dry paint from the color value of liquid paint according to claim 4, characterized in that: From dry reflectivity 2nd R Dry The color difference (ΔE*) between the predicted values ​​of CIE L*, a*, and b* of the second dried coating film and the measured values ​​of CIE L*, a*, and b* of the second dried coating film is 0.5 or less.

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