Method and device for detecting the content of chloride ions

Abstract

This application discloses a method and apparatus for detecting chloride ion content. The method for detecting chloride ion content includes: preparing a first volume of a test solution; adding a second volume of phosphoric acid solution to the test solution to form a test sample; adding silver nitrate solution dropwise to the test sample; and determining the chloride ion content in the test solution based on the potential change detected in the test sample. This method can improve the accuracy and stability of chloride ion content detection in browning solutions.

Description

Technical Field

[0001] This application belongs to the field of printed circuit board manufacturing technology, and in particular relates to a method and apparatus for detecting chloride ion content. Background Technology

[0002] In the production process of printed circuit boards (PCBs), a browning solution is typically used to treat the copper layer on the core board surface, forming an organic browning film on the copper surface. This improves the adhesion between the surface copper layer and the resin, thus enabling the fabrication of multilayer boards. The organic browning film is crucial for the preparation of multilayer boards, and the composition of the browning solution directly affects the quality of the organic browning film. Chloride ions are a key factor influencing the quality of the organic browning film.

[0003] However, the copper and sulfate ions in existing browning solutions often interfere with the testing of chloride ions, making it difficult to determine the accurate chloride ion content in the browning solution using existing testing methods. Summary of the Invention

[0004] This application provides a method and apparatus for detecting chloride ion content, in order to solve the technical problem that the presence of copper ions and sulfate ions in existing browning solutions usually interferes with the testing of chloride ions, thus making it difficult to accurately determine the chloride ion content in browning solutions.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a method for detecting chloride ion content, wherein the method for detecting chloride ion content includes:

[0006] Prepare the first volume of the test solution;

[0007] A second volume of phosphoric acid solution is added to the solution to be tested to form a sample to be tested.

[0008] A silver nitrate solution is added dropwise to the sample to be tested, and the chloride ion content in the solution is determined by detecting the potential change in the sample.

[0009] Optionally, the concentration of the phosphoric acid solution is not less than 85%, and the volume ratio of the first volume to the second volume is 5:1.5 to 5:2.5.

[0010] Optionally, the first volume is not less than 50 ml.

[0011] Optionally, the liquid to be tested is a browning liquid.

[0012] Optionally, the step of adding silver nitrate solution to the sample to be tested and determining the chloride ion content in the test solution by detecting the potential change in the sample to be tested includes:

[0013] Insert the detection electrode into the sample to be tested;

[0014] An equal amount of silver nitrate solution is added to the sample to be tested at preset time intervals.

[0015] Determine the total amount of silver nitrate solution added to the sample to be tested after each addition of the silver nitrate solution and the potential of the sample to be tested after each addition of the silver nitrate solution;

[0016] The stoichiometric point for titrating the sample to be tested with the silver nitrate solution is determined based on the total amount added and the potential.

[0017] The chloride ion content in the test solution is determined based on the amount of silver nitrate solution added at the stoichiometric point.

[0018] Optionally, determining the stoichiometric point for titrating the sample with the silver nitrate solution based on the total amount added and the potential includes:

[0019] With the total amount of liquid added as the horizontal axis and the potential as the vertical axis, a curve is established showing the change in the potential of the sample to be tested as a function of the total amount of silver nitrate solution added.

[0020] The stoichiometric point is determined based on the abrupt change point of the change curve.

[0021] Optionally, the surface of the detection electrode is coated with a sulfur-containing coating, and the step of inserting the detection electrode into the sample to be tested includes:

[0022] The portion of the detection electrode having the sulfur-containing coating is inserted into the sample to be tested.

[0023] Optionally, the step of adding phosphoric acid solution to the test solution to form the test sample includes:

[0024] Add phosphoric acid solution to the test solution and stir until homogeneous to form the sample to be tested.

[0025] To solve the above-mentioned technical problems, one technical solution adopted in this application is to provide a detection device, which includes a detection container, a feeding device, and a detection device.

[0026] The feeding device is used to sequentially inject a first volume of the test liquid and a second volume of phosphoric acid solution into the detection container to form the test sample;

[0027] The detection device includes a titration mechanism, a detection electrode, and a potential detection device electrically connected to the detection electrode. The detection electrode is inserted into the sample to be tested. The titration mechanism is used to add silver nitrate solution to the sample to be tested. The potential detection device detects the potential change in the sample to be tested and determines the chloride ion content in the solution to be tested based on the potential change.

[0028] Optionally, the detection device further includes a stirring mechanism, which extends into the detection container to stir the solution in the detection container.

[0029] The beneficial effects of this application are as follows: In the scheme of this application, by directly selecting a first volume of the test solution and adding a second volume of phosphoric acid solution to the first volume of the test solution to form the test sample, without the need to use DI water for volume dilution, the test sample in this embodiment is more acidic than the existing detection method. This allows some of the silver sulfate precipitate formed by sulfate ions and silver ions to be re-dissolved and ionized to form sulfate ions and silver ions. Therefore, the influence of the reaction between sulfate ions and silver ions to form a precipitate on the ion concentration in the test sample can be reduced, thus improving the accuracy of silver nitrate solution titration of chloride ions.

[0030] Furthermore, since the sample to be tested in this embodiment does not require dilution with DI water, the concentration of organic matter in the sample to be tested can be higher, thereby reducing the solubility of inorganic salts (silver chloride) in the sample to be tested. This further reduces the electrolysis of the formed silver chloride precipitate in the solution, allowing chloride ions to be more likely to be completely reacted. Therefore, the accuracy of silver nitrate solution titration of chloride ions can be further improved. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0032] Figure 1 This is a schematic flowchart of an embodiment of a method for detecting chloride ion content provided in this application;

[0033] Figure 2 This is a schematic diagram showing the change in the potential of the sample to be tested in this application as the total amount of silver nitrate solution added. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0036] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0037] In the manufacturing process of printed circuit boards, it is usually necessary to fix the metal conductive layer to the insulating substrate. For example, the metal conductive layer (usually copper foil) is fixed to the surface of the insulating substrate to form a core board or a prepreg is placed between two adjacent core boards. The metal conductive layer on the surface of the core board is fixed to the prepreg by hot pressing.

[0038] To improve the bonding stability between the conductive metal layer and the insulating substrate, a browning treatment is typically required for the conductive metal layer. This browning treatment involves reacting a browning solution with the conductive metal layer to form an organic browning film, thereby enhancing the adhesion between the conductive metal layer and the insulating substrate.

[0039] Since chloride ions in the browning solution are a key factor affecting the organic browning film, it is necessary to accurately measure the chloride ion concentration in the browning solution in order to conduct subsequent production evaluation of the browning solution.

[0040] The existing method for determining the chloride ion concentration in browning solution includes the following steps:

[0041] 1. Prepare the standardization solution.

[0042] The standardization solution can typically be prepared using a 1000 ppm chloride ion standard solution. For example, 2 ml of a 1000 ppm chloride ion standard solution can be selected, 20 ml of concentrated phosphoric acid can be added to this standard solution, and then DI water (deionized water or ultrapure water) can be added to bring the volume to 100 ml, thus obtaining 100 ml of standardization solution. The chloride ion concentration L1 of this standardization solution can then be determined by titration with silver chloride solution.

[0043] 2. Prepare the sample solution.

[0044] For the sample solution, take 10 ml of browning solution, add 2 ml of a 1000 ppm chloride ion standard solution to the 10 ml of browning solution, then add 20 ml of concentrated phosphoric acid, and finally add DI water to make up to 100 ml, thus obtaining 100 ml of sample solution. Then, the chloride ion concentration L2 of the sample solution is determined by titration with silver chloride solution.

[0045] The chloride ion concentration (in ppm) in the original browning solution can then be determined using the formula (L2-L1)*10.

[0046] The test results of the samples tested using existing detection methods are shown in Table 1 below.

[0047] Table 1

[0048]

[0049] The terms "2ml standard solution" and "2ml browning solution" indicate that the sample solution is prepared by adding 2ml of a standard solution with a chloride ion concentration of 1000ppm to 20ml of concentrated phosphoric acid, and then adding DI water to bring the volume to 100ml. "2ml standard solution + browning solution" indicates that the sample solution is prepared by mixing 2ml of a standard solution with a chloride ion concentration of 1000ppm and 10ml of browning solution, adding 20ml of concentrated phosphoric acid, and then adding DI water to bring the volume to 100ml. "3ml standard solution + browning solution" indicates that the sample solution is prepared by mixing 3ml of a standard solution with a chloride ion concentration of 1000ppm and 10ml of browning solution, adding 20ml of concentrated phosphoric acid, and then adding DI water to bring the volume to 100ml.

[0050] Existing detection methods are complex; moreover, browning solutions typically contain sulfate ions, which combine with silver ions to form a precipitate during titration with silver chloride solution, thus affecting the titration results and consequently impacting the accuracy of chloride ion concentration detection in browning solutions.

[0051] Please see Figure 1, Figure 1 This is a schematic flowchart of an embodiment of a method for detecting chloride ion content provided in this application.

[0052] The specific steps for detecting chloride ion content include:

[0053] S110: Prepare the first volume of the test solution.

[0054] In this step, a first volume of the test solution can be prepared, wherein the test solution can be the browning solution to be tested. The browning solution contains chloride ions (Cl). - ), nitric acid (HNO3), sulfuric acid (H2SO4), H2O2, copper ions (Cu) 2+ ) and pre-set organic matter.

[0055] The first volume can be no less than 50 ml, for example, the first volume can be 50, 60 or 70 ml.

[0056] S120: Add a second volume of phosphoric acid solution to the test solution to form the test sample.

[0057] After the test solution is prepared, a second volume of phosphoric acid solution can be added to the test solution to form the test sample.

[0058] In this step, the phosphoric acid solution can be a concentrated phosphoric acid solution with a concentration of not less than 85%, which provides the reaction environment for subsequent titration. A concentration of not less than 85% means that the volume of phosphoric acid in the concentrated phosphoric acid solution is not less than 85% of the volume of the phosphoric acid solution. The concentration of the phosphoric acid solution can be 85%, 90%, or 95%.

[0059] The volume ratio of the first volume to the second volume is 5:1.5 to 5:2.5.

[0060] Therefore, when the first volume is 50 ml, the second volume can be 15 to 25 ml. Specifically, the second volume can be 15, 20, or 25 ml.

[0061] In a preferred embodiment, when the first volume is 50 ml, the second volume can be 20 ml.

[0062] When phosphoric acid solution is added to the test solution, it can be stirred evenly to form the desired sample to be tested.

[0063] S130: Add silver nitrate solution to the sample to be tested, and determine the chloride ion content in the test solution based on the potential change in the sample.

[0064] After the sample to be tested is prepared in step S120, the chloride ion content in the original test solution can be determined by titrating the sample.

[0065] Specifically, titration can be performed using a silver nitrate solution with a preset concentration. The silver ions in the silver nitrate solution react with chloride ions to form silver chloride precipitate, thereby changing the ion concentration in the sample to be tested, which in turn changes the conductivity of the sample. Therefore, the chloride ion content can be determined by detecting the potential change in the sample.

[0066] One method is to use a 0.01 equivalent (0.01 mol / L) silver nitrate solution for titration.

[0067] Therefore, in this embodiment, by directly selecting a first volume of the test solution and adding a second volume of phosphoric acid solution to the first volume of the test solution to form the test sample, without the need for volume dilution with DI water, the test sample in this embodiment is more acidic than the existing detection method. This allows some of the silver sulfate precipitate formed by sulfate ions and silver ions to be re-dissolved and ionized to form sulfate ions and silver ions. Therefore, the influence of the reaction between sulfate ions and silver ions to form a precipitate on the ion concentration in the test sample can be reduced, thus improving the accuracy of silver nitrate solution titration of chloride ions.

[0068] Furthermore, since the sample to be tested in this embodiment does not require dilution with DI water, the concentration of organic matter in the sample to be tested can be higher, thereby reducing the solubility of inorganic salts (silver chloride) in the sample to be tested. This further reduces the electrolysis of the formed silver chloride precipitate in the solution, allowing chloride ions to be more likely to be completely reacted. Therefore, the accuracy of silver nitrate solution titration of chloride ions can be further improved.

[0069] Furthermore, in this embodiment, the titration of the chloride ion content in the sample to be tested using silver nitrate solution specifically includes the following steps:

[0070] a. Insert the detection electrode into the sample to be tested.

[0071] In this step, the sample to be tested can be electrically connected to an external power source, and the potential change of the sample to be tested can be detected through the detection electrode.

[0072] The detection electrode can be an electrode with a sulfur-containing coating. By inserting the sulfur-containing coating portion of the detection electrode into the sample to be tested, the interference of copper ions in the sample can be avoided, thereby improving the sensitivity of the detection electrode in detecting the potential change of the sample and further ensuring the accuracy of the detection of chloride ion content in the sample.

[0073] b. Add an equal amount of silver nitrate solution to the sample to be tested at preset time intervals.

[0074] In the process of inserting the detection electrode, an equal amount of silver nitrate solution can be added dropwise to the sample to be tested.

[0075] In this method, an equal amount of silver nitrate solution can be added to the sample to be tested at preset time intervals. For example, one or more drops of silver nitrate solution can be added to the sample to be tested each time, and after a preset time interval, an equal amount of silver nitrate solution can be added to the sample to be tested.

[0076] c. Determine the total amount of silver nitrate solution added to the sample after each addition and the potential of the sample after each addition.

[0077] The total amount of silver nitrate solution added can be recorded after each addition to the sample. For example, if 0.1 ml of silver nitrate solution is added each time, the total amount added for the first addition is 0.1 ml, the total amount added for the second addition is 0.2 ml, and so on.

[0078] After each addition of silver nitrate solution, the potential change of the sample to be tested can be detected by the detection electrode.

[0079] After each addition of silver nitrate solution and once the potential of the sample to be tested is detected to be stable, the next addition of silver nitrate solution can be performed, and the potential of the sample to be tested can be detected.

[0080] d. Determine the stoichiometric point for titrating the sample with silver nitrate solution based on the total amount added and the potential.

[0081] The stoichiometric point for titrating the sample with silver nitrate solution is determined based on the total amount added and the potential.

[0082] At the stoichiometric point, chloride ions in the sample are completely precipitated (silver chloride precipitate), and even if silver nitrate solution is added further, no new silver chloride precipitate will be formed. At this point, the total amount of silver nitrate solution added is exactly the amount that reacts completely with the chloride ions in the sample.

[0083] e. Determine the chloride ion content in the test solution based on the amount of silver nitrate solution added at the stoichiometric point.

[0084] Once the stoichiometric point is determined, the chloride ion content in the test solution can be calculated based on the amount of silver nitrate solution added and the concentration of that silver nitrate solution.

[0085] In this embodiment, a curve can be established showing the change in potential of the sample to be tested with the total amount of silver nitrate solution added, with the total amount added as the horizontal axis and the potential as the vertical axis; and the stoichiometric point can be determined based on the abrupt change point of the curve.

[0086] Please see Figure 2 , Figure 2 This is a schematic diagram showing the change in the potential of the sample to be tested in this application as the total amount of silver nitrate solution added.

[0087] The point where the slope of the curve changes abruptly corresponds to the stoichiometric point of the sample to be tested.

[0088] The test results of the samples tested using existing detection methods are shown in Table 2 below.

[0089] Table 2

[0090]

[0091] In Table 2, "1ml standard solution" means that the sample to be tested is 1ml of a standard solution with a chloride ion concentration of 1000ppm, diluted to 50ml with DI water; "browning" means that the sample to be tested is 50ml of browning solution; "0.5ml standard solution + browning" means that the sample to be tested is 0.5ml of standard solution added to 49.5ml of browning solution; "1ml standard solution + browning" means that the sample to be tested is 1ml of a standard solution with a chloride ion concentration of 1000ppm added to 49ml of browning solution. The units of the data in "Results" are ppm.

[0092] Comparing with Tables 1 and 2 above, it can be seen that the detection method corresponding to Table 2 yields stable and highly accurate results in detecting the concentration of chloride ions in the sample.

[0093] Furthermore, based on the same inventive concept, this application also provides a detection device. This detection device can be used to implement the above-described chloride ion detection method.

[0094] The testing device includes a testing container, a feeding device, and a testing device.

[0095] The feeding device is used to sequentially inject a first volume of the test liquid and a second volume of phosphoric acid solution into the detection container to form the test sample;

[0096] The detection device includes a titration mechanism, a detection electrode, and a potential detection device electrically connected to the detection electrode. The detection electrode is inserted into the sample to be tested. The titration mechanism is used to add silver nitrate solution to the sample to be tested. The potential detection device detects the potential change in the sample to be tested and determines the chloride ion content in the test solution based on the potential change.

[0097] For details on how the detection device detects the chloride ion content in the test solution, please refer to the previous text, which will not be repeated here.

[0098] In addition, the detection device also includes a stirring mechanism, which is inserted into the detection container to stir the solution in the detection container.

[0099] In summary, those skilled in the art will readily understand that the beneficial effects of this application are as follows: In the scheme of this application, by directly selecting a first volume of the test solution and adding a second volume of phosphoric acid solution to the first volume of the test solution to form the test sample, without the need for volume dilution with DI water, the test sample in this embodiment is more acidic than the existing detection method. This allows some of the silver sulfate precipitate formed by sulfate ions and silver ions to be re-dissolved and ionized to form sulfate ions and silver ions. Therefore, the influence of the reaction between sulfate ions and silver ions to form a precipitate on the ion concentration in the test sample can be reduced, thereby improving the accuracy of chloride ion titration by silver nitrate solution.

[0100] Furthermore, since the sample to be tested in this embodiment does not require dilution with DI water, the concentration of organic matter in the sample to be tested can be higher, thereby reducing the solubility of inorganic salts (silver chloride) in the sample to be tested. This further reduces the electrolysis of the formed silver chloride precipitate in the solution, allowing chloride ions to be more likely to be completely reacted. Therefore, the accuracy of silver nitrate solution titration of chloride ions can be further improved.

[0101] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for detecting chloride ion content, characterized in that, The method for detecting chloride ion content includes: Prepare a first volume of the test solution, wherein the test solution is a browning solution; A second volume of phosphoric acid solution is added to the solution to be tested to form a sample to be tested. The detection electrode is inserted into the sample to be tested, and silver nitrate solution is dropped into the sample to be tested. The chloride ion content in the sample to be tested is determined by detecting the potential change in the sample to be tested. The detection electrode has a sulfur-containing coating on its surface. The potential change of the sample to be tested is detected by inserting the portion of the detection electrode with the sulfur-containing coating into the sample to be tested.

2. The method for detecting chloride ion content according to claim 1, characterized in that, The concentration of the phosphoric acid solution is not less than 85%, and the volume ratio of the first volume to the second volume is 5:1.5 to 5:2.

5.

3. The method for detecting chloride ion content according to claim 1, characterized in that, The first volume is not less than 50 ml.

4. The method for detecting chloride ion content according to any one of claims 1-3, characterized in that, The step of adding silver nitrate solution to the sample to be tested and determining the chloride ion content in the test solution by detecting the potential change in the sample to be tested includes: An equal amount of silver nitrate solution is added to the sample to be tested at preset time intervals. Determine the total amount of silver nitrate solution added to the sample to be tested after each addition of the silver nitrate solution and the potential of the sample to be tested after each addition of the silver nitrate solution; The stoichiometric point for titrating the sample to be tested with the silver nitrate solution is determined based on the total amount added and the potential. The chloride ion content in the test solution is determined based on the amount of silver nitrate solution added at the stoichiometric point.

5. The method for detecting chloride ion content according to claim 4, characterized in that, The determination of the stoichiometric point for titrating the sample with the silver nitrate solution based on the total amount added and the potential includes: With the total amount of liquid added as the horizontal axis and the potential as the vertical axis, a curve is established showing the change in the potential of the sample to be tested as a function of the total amount of silver nitrate solution added. The stoichiometric point is determined based on the abrupt change point of the change curve.

6. The method for detecting chloride ion content according to claim 1, characterized in that, The step of adding phosphoric acid solution to the test solution to form the test sample includes: Add phosphoric acid solution to the test solution and stir until homogeneous to form the sample to be tested.

7. A detection device, characterized in that, The detection device includes: a detection container, a feeding device, and a detection device; The feeding device is used to sequentially inject a first volume of the test liquid and a second volume of phosphoric acid solution into the detection container to form a test sample, wherein the test liquid is a browning solution; The detection device includes a titration mechanism, a detection electrode, and a potential detection device electrically connected to the detection electrode. The detection electrode is inserted into the sample to be tested. The titration mechanism is used to add silver nitrate solution to the sample to be tested. The potential detection device detects the potential change in the sample to be tested and determines the chloride ion content in the solution to be tested based on the potential change.

8. The detection device according to claim 7, characterized in that, The detection device further includes a stirring mechanism, which extends into the detection container to stir the solution in the detection container.

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