Method for detecting solvent content in a coating and method for drying a catalytic layer

Abstract

The embodiment of the application provides a kind of coating solvent content detection method and catalytic layer drying method, it is related to detection technical field, coating solvent content detection method includes the following steps: prepare a series of different area density solvent-containing coating samples, obtain the relationship of X-Ray attenuation intensity and area density of solvent-containing coating, the relationship of β-Ray attenuation intensity and area density;Solvent-containing coating sample is completely dried to obtain a series of different area density completely dry coating sample, obtain the relationship of X-Ray attenuation intensity and area density of completely dry coating, the relationship of β-Ray attenuation intensity and area density;The X-Ray attenuation intensity of detection obtained, β-Ray attenuation intensity of the coating to be measured, and calculate the solvent content in the coating to be measured.The detection method and drying method of the embodiment of the application can non-contact measurement on the solvent content in the coating, realize the online, accurate detection of solvent content in the preparation process of catalytic layer.

Description

Technical Field

[0001] This application relates to the field of detection technology, and more specifically, to a method for detecting the solvent content in a coating and a method for drying a catalyst layer. Background Technology

[0002] The catalyst-coated membrane (CCM) in a proton exchange membrane fuel cell or proton exchange membrane water electrolyzer is a catalyst / proton exchange membrane module prepared by coating both sides of the proton exchange membrane with a catalyst-containing catalytic layer. To ensure the quality of the catalytic layer, it is necessary to detect the solvent content in the dried catalytic layer. Currently, the solvent content in the catalytic layer is usually detected offline, by calculating the weight loss after the catalytic layer has been completely dried. Offline detection lacks timeliness, making it impossible to monitor the solvent content during the catalytic layer preparation process in a timely manner; moreover, offline detection is subject to many human factors, which can easily lead to errors.

[0003] Currently, various online testing technologies applied to the catalyst layer preparation process are limited and cannot detect solvent content in real time. Sensors used to detect the surface temperature of the catalyst layer, sensors used to detect the surface gloss or brightness of the catalyst layer, sensors used to detect the surface reflected light of the catalyst layer, non-contact moisture meters that detect moisture in the catalyst layer by measuring the energy of infrared light emitted from the catalyst layer surface, and image processing units that capture images of the catalyst layer surface and quantify the surface state based on the images, can only assess the dryness of the catalyst layer to a certain extent, with a greater emphasis on qualitative assessment. They cannot accurately assess the solvent content level in the catalyst layer in real time and lack quantitative feedback on solvent content. Summary of the Invention

[0004] The purpose of this application is to provide a method for detecting the solvent content in a coating and a method for drying a catalyst layer, which can perform non-contact measurement of the solvent content in the coating and realize online and accurate detection of the solvent content in the catalyst layer preparation process.

[0005] In a first aspect, embodiments of this application provide a method for detecting the solvent content in a coating, which includes the following steps:

[0006] Prepare a series of solvent-containing coating samples with different areal densities, and use X-Ray and β-Ray to detect each solvent-containing coating sample to obtain the relationship between X-Ray attenuation intensity and areal density, and the relationship between β-Ray attenuation intensity and areal density of the solvent-containing coating.

[0007] A series of completely dry coating samples with different areal densities were obtained by completely drying the solvent-containing coating samples. X-Ray and β-Ray were used to detect each completely dry coating sample to obtain the relationship between X-Ray attenuation intensity and areal density, and the relationship between β-Ray attenuation intensity and areal density of the completely dry coating.

[0008] The coating under test was detected by X-Ray and β-Ray measurements to obtain the X-Ray attenuation intensity and β-Ray attenuation intensity of the coating under test. Based on the relationship between X-Ray attenuation intensity and areal density, and the relationship between β-Ray attenuation intensity and areal density of solvent-containing coating and completely dry coating, the solvent content in the coating under test was calculated.

[0009] In the above technical solution, since the solvent absorbs β-rays more readily than X-rays, the solvent content in the coating can be assessed by measuring the difference in solvent loading (specifically, attenuation intensity) between the completely dry coating and the solvent under X-ray and β-ray conditions. This detection method utilizes X-ray and β-ray to detect the coating, enabling non-contact measurement of the solvent content and achieving online and accurate detection of solvent content during the catalyst layer preparation process.

[0010] In one possible implementation, the X-Ray attenuation intensity and areal density relationship of the solvent is obtained based on the X-Ray attenuation intensity and areal density relationship of the solvent-containing coating and the X-Ray attenuation intensity and areal density relationship of the completely dried coating.

[0011] Based on the relationship between β-Ray attenuation intensity and areal density of solvent-containing coatings and the relationship between β-Ray attenuation intensity and areal density of fully dried coatings, the relationship between β-Ray attenuation intensity and areal density of solvents is obtained.

[0012] Substituting the X-Ray attenuation intensity and β-Ray attenuation intensity of the coating under test into the above relationship, the areal density of the completely dry coating and the areal density of the solvent are calculated, and then the solvent content in the coating under test is calculated.

[0013] In the above technical solution, the X-Ray and β-Ray attenuation intensity and areal density relationship of the solvent-containing coating and the X-Ray and β-Ray attenuation intensity and areal density relationship of the completely dried coating are first used to obtain the X-Ray and β-Ray attenuation intensity and areal density relationship of the solvent, and then the solvent content in the coating to be tested is calculated.

[0014] One possible implementation includes the following steps:

[0015] A series of solvent-containing coating samples were obtained with areal density S and corresponding X-Ray attenuation intensity A. A series of completely dried coating samples were obtained with areal density T and corresponding X-Ray attenuation intensity B. The relationship between X-Ray attenuation intensity and areal density of the completely dried coating was linearly fitted to obtain the formula B = k1T + b1. The relationship between X-Ray attenuation intensity and areal density of the solvent was linearly fitted to obtain the formula AB = k2(ST) + b2.

[0016] A series of solvent-containing coating samples were obtained with areal density S and corresponding β-Ray attenuation intensity C. A series of completely dried coating samples were obtained with areal density T and corresponding β-Ray attenuation intensity D. The relationship between β-Ray attenuation intensity and areal density of the completely dried coating was linearly fitted to obtain the formula D = k3T + b3. The relationship between β-Ray attenuation intensity and areal density of the solvent was linearly fitted to obtain the formula CD = k4(ST) + b4.

[0017] The standard relationship between the attenuation intensity E1 of the X-Ray of the coating to be tested and the areal density X1 of the completely dried coating and the areal density X2 of the solvent was determined, and the standard curve relationship E1=(k1X1+b1)+(k2X2+b2) was obtained.

[0018] The standard relationship between the attenuation intensity F1 of the β-Ray of the coating to be tested and the areal density X1 of the completely dried coating and the areal density X2 of the solvent was determined, and the standard curve relationship F1=(k3X1+b3)+(k4X2+b4) was obtained.

[0019] Substitute the measured values ​​of the X-Ray attenuation intensity E1 and β-Ray attenuation intensity F1 of the coating under test into the standard curve relationship to obtain the specific values ​​of X1 and X2, and calculate the solvent content of the coating under test W = X2 / (X1+X2).

[0020] In the above technical solution, the standard curve relationship of the coating under test under X-Ray and β-Ray conditions is first plotted. Then, combined with the specific values ​​of the X-Ray attenuation intensity and β-Ray attenuation intensity of the coating under test, a two-variable linear equation is designed regarding the areal density of the completely dry coating and the areal density of the solvent in the coating under test. The solvent content in the coating under test is then calculated. This method can detect the solvent content in the coating online and accurately.

[0021] In one possible implementation, the number of solvent-coated samples is 3-7, and the difference in density between adjacent surfaces is 0.07-0.13 mg / cm³. 2 .

[0022] In the above technical solution, selecting 3-7 samples can yield a relatively accurate standard curve relationship between attenuation intensity and areal density.

[0023] In one possible implementation, the solvent-containing coating sample is a dried coating sample, and the coating to be tested is a dried coating with a drying temperature of 100-170℃ and a drying time of 0.5-5min.

[0024] In the above technical solution, both the solvent-containing coating sample and the coating to be tested are dried so that the solvent-containing coating sample can simulate the coating to be tested, thereby obtaining the standard curve relationship of the coating to be tested.

[0025] In one possible implementation, the X-ray attenuation intensity is detected using an X-ray load measurement device, and the β-ray attenuation intensity is detected using a β-ray load measurement device.

[0026] In one possible implementation, X-Ray attenuation intensity and β-Ray attenuation intensity are detected at the same site on a solvent-containing coating sample; X-Ray attenuation intensity and β-Ray attenuation intensity are detected at the same site on a completely dried coating sample; and X-Ray attenuation intensity and β-Ray attenuation intensity are detected at the same site on the coating to be tested.

[0027] In the above technical solution, X-Ray and β-Ray detection are performed on the same site to reduce errors.

[0028] Secondly, embodiments of this application provide a method for drying a catalyst layer, which includes the following steps:

[0029] The catalyst layer coated on the substrate is dried.

[0030] The solvent content in the coating provided in the first aspect is detected by detecting the solvent content in the dried catalyst layer to obtain the solvent content in the catalyst layer;

[0031] The drying status of the catalyst layer is assessed based on the solvent content of the catalyst layer, so as to provide feedback for adjusting the drying conditions.

[0032] In the above technical solution, during the preparation of the catalyst layer, the solvent content in the dried catalyst is detected online and accurately. The drying conditions are adjusted based on the evaluated drying state of the catalyst, thereby preparing a catalyst layer that meets the drying requirements.

[0033] One possible implementation includes the following steps:

[0034] The catalyst layer is continuously conveyed through an oven for drying.

[0035] The X-ray attenuation intensity and β-ray attenuation intensity of the dried catalyst layer were detected by X-ray load measurement equipment and β-ray load measurement equipment set downstream of the oven to obtain the solvent content in the catalyst layer.

[0036] The oven's operating status is adjusted based on feedback from the solvent content of the catalyst layer.

[0037] The above technical solution enables continuous preparation of the catalyst layer, thereby improving production efficiency.

[0038] In one possible implementation, during the continuous delivery of the catalyst layer, an X-ray load measuring device and a β-ray load measuring device scan and detect in real time along the width direction of the catalyst layer;

[0039] The X-ray load measurement device and the β-ray load measurement device are simultaneously connected to the terminal, which calculates the solvent content in the catalyst layer and provides feedback adjustment.

[0040] In the above technical solution, the X-ray load measurement device and the β-ray load measurement device are connected in series to realize the real-time detection of the solvent content in the catalyst layer in an automated manner. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic flowchart of a method for drying a catalyst layer provided in an embodiment of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0044] The following describes in detail the method for detecting the solvent content in the coating and the drying method for the catalyst layer in the embodiments of this application.

[0045] This application provides a method for detecting the solvent content in a coating, which includes the following steps:

[0046] I. Plotting the Standard Curve:

[0047] Prepare a series of solvent-containing coating samples with different areal densities, and use X-Ray and β-Ray to detect each solvent-containing coating sample to obtain the relationship between X-Ray attenuation intensity and areal density, and the relationship between β-Ray attenuation intensity and areal density of the solvent-containing coating.

[0048] A series of completely dry coating samples with different areal densities were obtained by completely drying the solvent-containing coating samples. X-Ray and β-Ray were used to detect each completely dry coating sample to obtain the relationship between X-Ray attenuation intensity and areal density, and the relationship between β-Ray attenuation intensity and areal density of the completely dry coating.

[0049] In the embodiments of this application, X-Ray attenuation intensity refers to the degree of attenuation of the detected X-Ray intensity, and β-Ray attenuation intensity refers to the degree of attenuation of the detected β-Ray intensity.

[0050] The samples examined using X-ray and β-ray can be from the same series or different series. For simplicity, the samples examined using X-ray and β-ray are from the same series, specifically the same series of solvent-containing coating samples and the same series of completely dried coating samples.

[0051] In some embodiments of this application, the number of solvent-containing coating samples is 3-7, and the number of completely dried coating samples is 3-7.

[0052] In some embodiments of this application, the solvent-containing coating sample is a coating sample that has been coated and then subjected to the same drying treatment but is not completely dried. The coating to be tested is a coating that has undergone drying treatment. The drying conditions are: drying temperature of 100-170℃ and drying time of 0.5-5min.

[0053] Surface density (also known as planar density or area density) is the mass per unit area of ​​a material of a specified thickness. In this embodiment, solvent-containing coating samples with different surface densities refer to coatings of different thicknesses applied using the same composition of paint. For example, by fixing the coating rate and controlling the amount of paint applied per unit time, solvent-containing coating samples with different surface densities are obtained. The surface density can be measured using a high-precision balance. After each solvent-containing coating sample with a different surface density is completely dried, a series of completely dried coating samples with different surface densities are obtained.

[0054] In some embodiments of this application, the difference in adjacent areal density between solvent-coated samples and / or fully dried coated samples is 0.07-0.13 mg / cm³. 2 .

[0055] In some embodiments of this application, X-ray attenuation intensity is detected using an X-ray load measurement device, and β-ray attenuation intensity is detected using a β-ray load measurement device.

[0056] For example, the X-ray load measurement device is an X-ray thickness gauge. An X-ray thickness gauge is an instrument that measures the thickness of a material by utilizing the characteristic that the intensity change (intensity attenuation) of X-rays as they penetrate the material being measured is related to the material's thickness. It is a non-contact, dynamic metrological instrument. In this embodiment, the X-ray attenuation intensity can be detected using an X-ray thickness gauge. Specifically, the X-ray attenuation intensity can be represented by the X-ray intensity attenuation ratio, where X-ray intensity attenuation ratio = (I0 - I) / I0, where I0 is the initial X-ray intensity and I is the final X-ray intensity. This facilitates the detection and investigation of the relationship between X-ray attenuation intensity and areal density.

[0057] For example, the beta-ray load measurement device is a beta-ray thickness gauge. A beta-ray thickness gauge is an instrument that measures thickness based on the principle that the intensity attenuation of beta rays passing through the object being measured is proportional to the thickness of the object. In this embodiment, the beta-ray attenuation intensity can be detected using a beta-ray thickness gauge. Specifically, the beta-ray attenuation intensity can be represented by the beta-ray intensity attenuation ratio, where the beta-ray intensity attenuation ratio = (L0 - L) / L0, where L0 is the initial beta-ray intensity and L is the final beta-ray intensity. This facilitates the detection and investigation of the relationship between beta-ray attenuation intensity and areal density.

[0058] In this embodiment, the X-Ray attenuation intensity and β-Ray attenuation intensity are detected at the same site on the solvent-containing coating sample; the X-Ray attenuation intensity and β-Ray attenuation intensity are also detected at the same site on the completely dried coating sample, so as to reduce the detection error caused by the difference in X-Ray attenuation intensity at different sites.

[0059] II. Real-time detection of the coating under test:

[0060] The coating under test was detected by X-Ray and β-Ray measurements to obtain the X-Ray attenuation intensity and β-Ray attenuation intensity of the coating under test. Based on the relationship between X-Ray attenuation intensity and areal density, and the relationship between β-Ray attenuation intensity and areal density of solvent-containing coating and completely dry coating, the solvent content in the coating under test was calculated.

[0061] In this embodiment of the application, the X-Ray attenuation intensity and β-Ray attenuation intensity are detected at the same site of the coating to be tested, so as to reduce the detection error caused by the difference in X-Ray attenuation intensity at different sites.

[0062] Based on the above scheme, the method for detecting the solvent content in the coating includes the following steps:

[0063] Based on the relationship between X-Ray attenuation intensity and areal density of solvent-containing coatings and the relationship between X-Ray attenuation intensity and areal density of fully dried coatings, the relationship between X-Ray attenuation intensity and areal density of solvents is obtained.

[0064] Based on the relationship between β-Ray attenuation intensity and areal density of solvent-containing coatings and the relationship between β-Ray attenuation intensity and areal density of fully dried coatings, the relationship between β-Ray attenuation intensity and areal density of solvents is obtained.

[0065] Substituting the X-Ray attenuation intensity and β-Ray attenuation intensity of the coating under test into the above relationship, the areal density of the completely dry coating and the areal density of the solvent are calculated, and then the solvent content in the coating under test is calculated.

[0066] As one implementation method, the method for detecting the solvent content in the coating includes the following steps:

[0067] (1) Plotting the X-Ray standard curve:

[0068] The areal density of the solvent-containing coating sample is S, and the corresponding X-Ray attenuation intensity is A. The areal density of the completely dried coating sample is T, and the corresponding X-Ray attenuation intensity is B.

[0069] For example, seven solvent-coated samples were tested under X-ray conditions, and the data obtained are shown in the table below:

[0070] areal density S1 S2 S3 S4 S5 S6 S7 X-Ray attenuation intensity A1 A2 A3 A4 A5 A6 A7

[0071] Seven fully dried coating samples were tested under X-ray conditions, and the data are shown in the table below:

[0072] areal density T1 T2 T3 T4 T5 T6 T7 X-Ray attenuation intensity B1 B2 B3 B4 B5 B6 B7

[0073] By linearly fitting the relationship between the X-Ray attenuation intensity and the areal density of the fully dried coating, i.e. the B / T relationship, we obtain the formula B = k1T + b1.

[0074] By linearly fitting the relationship between the X-Ray attenuation intensity (AB) and the areal density (ST) of the solvent, i.e., the (AB) / (ST) relationship, we obtain the formula AB = k2(ST) + b2.

[0075] (2) Plotting the β-Ray standard curve:

[0076] The areal density of the solvent-containing coating sample is S, and the corresponding β-Ray attenuation intensity is C. The areal density of the completely dried coating sample is T, and the corresponding β-Ray attenuation intensity is D.

[0077] For example, seven solvent-coated samples were tested under β-Ray conditions, and the data obtained are shown in the table below:

[0078] areal density S1 S2 S3 S4 S5 S6 S7 β-Ray attenuation intensity C1 C2 C3 C4 C5 C6 C7

[0079] Seven fully dried coating samples were tested under β-Ray conditions, and the data are shown in the table below:

[0080]

[0081]

[0082] By linearly fitting the relationship between the β-Ray attenuation intensity and the areal density of the fully dried coating, i.e. the D / T relationship, we obtain the formula D = k3T + b3.

[0083] By linearly fitting the relationship between the β-Ray attenuation intensity and the areal density of the solvent, i.e., the (CD) / (ST) relationship, we obtain the formula CD=k4(ST)+b4.

[0084] (3) Determine the standard relationship between the attenuation intensity E1 of the X-Ray of the coating to be tested and the areal density X1 of the completely dried coating and the areal density X2 of the solvent, and obtain the standard curve relationship E1=(k1X1+b1)+(k2X2+b2).

[0085] (4) The standard relationship between the attenuation intensity F1 of the β-Ray of the coating to be tested and the areal density X1 of the completely dried coating and the areal density X2 of the solvent is determined, and the standard curve relationship F1=(k3X1+b3)+(k4X2+b4) is obtained.

[0086] (5) Substitute the measured values ​​of the X-Ray attenuation intensity E1 and β-Ray attenuation intensity F1 of the coating under test into the above two standard curve relationships to calculate the specific values ​​of X1 and X2, and then calculate the content of solvent in the coating under test W = X2 / (X1+X2).

[0087] The detection method of this application embodiment does not impose specific restrictions on the coating. It only requires that a solvent-containing coating sample and a completely dried coating sample be prepared in advance using the same paint composition as the coating to be tested, and that the X-Ray standard curve relationship and β-Ray standard curve relationship be plotted according to the above method.

[0088] This application also provides a method for drying a catalyst layer, which includes the following steps:

[0089] S1. Dry the catalyst layer coated on the substrate;

[0090] S2. The solvent content in the coating of the aforementioned embodiment is detected by detecting the solvent content in the dried catalyst layer to obtain the solvent content in the catalyst layer.

[0091] S3. Assess the drying state of the catalyst layer based on the solvent content of the catalyst layer, and adjust the drying conditions accordingly.

[0092] Please refer to Figure 1 As one implementation method, the drying method for the catalyst layer includes the following steps:

[0093] S1. Products coated with a catalyst layer (such as CCM) are continuously conveyed through an oven for drying.

[0094] S2. The X-ray attenuation intensity and β-ray attenuation intensity of the dried catalyst layer are detected by X-ray load measuring equipment (such as an X-ray thickness gauge) and β-ray load measuring equipment (such as a β-ray thickness gauge) set downstream of the oven, so as to calculate the solvent content in the catalyst layer.

[0095] S3. Adjust the working status of the oven (such as air volume, temperature, etc.) based on the solvent content of the catalyst layer.

[0096] In some embodiments of this application, during the continuous delivery of the catalyst layer (specifically during the CCM coating preparation process), an X-ray load measuring device (X-Ray thickness gauge) and a β-ray load measuring device (β-Ray thickness gauge) are used to scan and detect the catalyst layer in real time along its width direction. The X-ray load measuring device and the β-ray load measuring device are connected synchronously to ensure that the measurement points before and after coating are the same.

[0097] The X-ray load measurement device and the β-ray load measurement device are simultaneously connected to the terminal, which calculates the solvent content in the catalyst layer and provides feedback adjustment.

[0098] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0099] Example 1

[0100] This embodiment provides a method for detecting the solvent content in a coating, the specific process of which is as follows:

[0101] (1) Plotting the X-Ray standard curve:

[0102] Five solvent-containing coating samples with different areal densities were prepared. The composition of the solvent-containing coating samples was the same as that of the catalyst layer to be tested. A coating containing 1 part by weight of platinum-carbon catalyst, 5 parts by weight of perfluorosulfonic acid film solution, and 8 parts by weight of water-alcohol solution (water-alcohol ratio of 1) was applied to the substrate and dried at 150°C for 2 minutes. By fixing the coating rate and controlling the coating amount per unit time, solvent-containing coating samples with different areal densities were obtained. The areal density S and the corresponding X-ray intensity attenuation ratio A of each solvent-containing coating sample were obtained using an X-ray thickness gauge, as shown in the table below:

[0103] <![CDATA[Areal density (mg / cm 2 )]]> 0.154 0.248 0.366 0.467 0.572 X-Ray intensity attenuation percentage (%) 1.201 2.473 4.615 6.126 7.594

[0104] Five completely dried coating samples with different areal densities were obtained by completely drying the solvent-containing coating samples. Each completely dried coating sample was then tested using an X-ray thickness gauge to obtain the areal density T and the corresponding X-ray intensity attenuation ratio B, as shown in the table below:

[0105] <![CDATA[Areal density (mg / cm 2 )]]> 0.143 0.23 0.342 0.439 0.538 X-Ray intensity attenuation percentage (%) 1.156 2.415 4.551 6.053 7.513

[0106] By linearly fitting the relationship between the X-Ray intensity attenuation ratio and the areal density of the fully dried coating, i.e. the B / T relationship, the formula B = 0.156T - 0.0124 is obtained.

[0107] By linearly fitting the relationship between the X-Ray intensity attenuation ratio and the areal density of the solvent, i.e., the (AB) / (ST) relationship, we obtain the formula AB = 0.0155(ST) + 0.0003.

[0108] (2) Plotting the β-Ray standard curve:

[0109] The five solvent-containing coating samples were tested using a β-Ray thickness gauge to obtain the areal density S and the corresponding β-Ray intensity attenuation ratio C of the solvent-containing coating samples, as shown in the table below:

[0110] <![CDATA[areal density (mg / cm 2 )]]> 0.154 0.248 0.366 0.467 0.572 β-Ray intensity attenuation percentage (%) 0.822 1.742 2.656 3.784 4.588

[0111] The areal density T and corresponding β-Ray intensity attenuation ratio D of the five completely dried coating samples were measured using a β-Ray thickness gauge, as shown in the table below:

[0112] <![CDATA[Areal density (mg / cm 2 )]]> 0.143 0.23 0.342 0.439 0.538 β-Ray intensity attenuation percentage (%) 0.780 1.653 2.513 3.595 4.354

[0113] By linearly fitting the relationship between the β-Ray strength attenuation ratio and the areal density of the fully dried coating, i.e. the D / T relationship, the formula D = 0.0907T - 0.0056 is obtained.

[0114] By linearly fitting the relationship between the β-Ray intensity attenuation ratio and the areal density of the solvent, i.e., the (CD) / (ST) relationship, we obtain the formula CD = 0.0859(ST) - 0.0006.

[0115] (3) The standard relationship between the intensity attenuation ratio E1 of the X-Ray of the coating to be tested and the areal density X1 of the completely dried coating and the areal density X2 of the solvent was determined, and the standard curve relationship was obtained as E1 = (0.156X1 - 0.0124) + (0.0155X2 + 0.0003).

[0116] (4) The standard relationship between the intensity attenuation ratio F1 of the β-Ray of the coating to be tested and the areal density X1 of the fully dried coating and the areal density X2 of the solvent was determined, and the standard curve relationship was obtained as F1 = (0.0907X1 - 0.0056) + (0.0859X2 - 0.0006).

[0117] (5) Using an X-Ray thickness gauge, the X-Ray intensity attenuation ratio of the coating under test was found to be E1 = 1.361%. Using a β-Ray thickness gauge, the β-Ray intensity attenuation ratio of the coating under test was found to be F1 = 0.936%. Substituting the measured values ​​of E1 and F1 into the above two standard curve relationships, the solution was obtained jointly:

[0118] 1.361%=(0.156X1-0.0124)+(0.0155X2+0.0003);

[0119] 0.936%=(0.0907X1-0.0056)+(0.0859X2-0.0006);

[0120] The calculated value is X1 = 0.164 mg / cm³. 2 X2 = 0.008 mg / cm³ 2 .

[0121] The solvent content of the coating to be tested is calculated as W = X2 / (X1+X2) = 4.7%.

[0122] In summary, the solvent content detection method and catalyst layer drying method of the embodiments of this application can perform non-contact measurement of the solvent content in the coating, and realize online and accurate detection of the solvent content in the catalyst layer preparation process.

[0123] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for detecting the solvent content in a coating, characterized in that, It includes the following steps: Prepare a series of solvent-containing coating samples with different areal densities, and use X-Ray and β-Ray to detect each of the solvent-containing coating samples respectively; The solvent-containing coating sample was completely dried to obtain a series of completely dried coating samples with different areal densities. Each of the completely dried coating samples was tested using X-Ray and β-Ray. A series of solvent-containing coating samples were obtained with surface density S and corresponding X-Ray attenuation intensity A, and a series of fully dried coating samples were obtained with surface density T and corresponding X-Ray attenuation intensity B. The relationship between X-Ray attenuation intensity and surface density of the fully dried coating was linearly fitted to obtain the formula B=k1T+b1. By linearly fitting the relationship between the X-Ray attenuation intensity and the areal density of the solvent, the formula AB=k2(ST)+b2 is obtained; A series of solvent-containing coating samples were obtained with surface density S and corresponding β-Ray attenuation intensity C. A series of fully dried coating samples were obtained with surface density T and corresponding β-Ray attenuation intensity D. The relationship between β-Ray attenuation intensity and surface density of the fully dried coating was linearly fitted to obtain the formula D=k3T+b3. By linearly fitting the relationship between the β-Ray decay intensity and the areal density of the solvent, the formula CD=k4(ST)+b4 is obtained; The standard relationship between the attenuation intensity E1 of the X-Ray of the coating to be tested and the areal density X1 of the completely dried coating and the areal density X2 of the solvent was determined, and the standard curve relationship E1=(k1X1+b1)+(k2X2+b2) was obtained. The standard relationship between the attenuation intensity F1 of the β-Ray of the coating to be tested and the areal density X1 of the fully dried coating and the areal density X2 of the solvent was determined, and the standard curve relationship F1=(k3X1+b3)+(k4X2+b4) was obtained. The coating under test is detected by X-Ray and β-Ray measurements respectively to obtain the X-Ray attenuation intensity and β-Ray attenuation intensity of the coating under test. The specific values ​​of the measured X-Ray attenuation intensity E1 and β-Ray attenuation intensity F1 of the coating under test are substituted into the standard curve relationship to obtain the specific values ​​of X1 and X2. The solvent content of the coating under test is calculated as W = X2 / (X1+X2).

2. The method for detecting solvent content in a coating according to claim 1, characterized in that, The number of solvent-containing coating samples is 3-7, and the difference in density between adjacent surfaces is 0.07-0.13 mg / cm³. 2 .

3. The method for detecting solvent content in a coating according to claim 1 or 2, characterized in that, The solvent-containing coating sample is a dried coating sample, and the coating to be tested is a dried coating with a drying temperature of 100-170℃ and a drying time of 0.5-5min.

4. The method for detecting solvent content in a coating according to claim 1, characterized in that, The X-ray attenuation intensity was detected using an X-ray load measurement device, and the β-ray attenuation intensity was detected using a β-ray load measurement device.

5. The method for detecting solvent content in a coating according to claim 1, characterized in that, X-Ray attenuation intensity and β-Ray attenuation intensity were measured at the same site on solvent-containing coating samples; X-Ray attenuation intensity and β-Ray attenuation intensity were measured at the same site on completely dried coating samples; X-Ray attenuation intensity and β-Ray attenuation intensity were measured at the same site on the coating to be tested.

6. A method for drying a catalyst layer, characterized in that, It includes the following steps: The catalyst layer coated on the substrate is dried. The solvent content in the coating as described in any one of claims 1 to 5 is used to detect the solvent content in the dried catalyst layer to obtain the solvent content in the catalyst layer. The drying state of the catalyst layer is assessed based on its solvent content to provide feedback for adjusting the drying conditions.

7. The method for drying the catalyst layer according to claim 6, characterized in that, It includes the following steps: The catalyst layer is continuously conveyed through an oven for the drying process. The X-ray attenuation intensity and β-ray attenuation intensity of the dried catalyst layer are detected by X-ray load measuring device and β-ray load measuring device located downstream of the oven to obtain the solvent content in the catalyst layer. The working status of the oven is adjusted based on the solvent content of the catalyst layer.

8. The method for drying the catalyst layer according to claim 7, characterized in that, During the continuous delivery of the catalyst layer, the X-ray load measuring device and the β-ray load measuring device scan and detect in real time along the width direction of the catalyst layer; The X-ray load measuring device and the β-ray load measuring device are both connected to a terminal, which calculates the solvent content in the catalyst layer and provides feedback adjustment.

Images