Surface tension test method for detecting non-flowable glue

Abstract

The embodiment of the invention provides a surface tension testing method for detecting glue with non-flowability. The testing method comprises the following steps: preparing a base material, wherein a groove is formed in the surface of the base material; filling to-be-tested glue into the groove, and ensuring that the surface of the to-be-tested glue is flush with the opening of the groove; a liquid injection device is provided, distilled water is contained in the liquid injection device, and the liquid dropping speed range of the liquid injection device is set to be 0.2 microliter to 0.5 microliter per second; distilled water is dropwise added to at least three different positions on the surface of the glue through the liquid injection device, so that at least three liquid drops are formed; the contact angle of each liquid drop is calculated, and the contact angles of at least three target liquid drops are obtained; and determining the surface tension of the non-flowable glue to be measured according to the calculated contact angle of each target liquid drop.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of glue surface testing. More specifically, the embodiments of the present application relate to a surface tension testing method for detecting non-fluid glue. Background Art

[0002] At present, contact angle measurement is a commonly used method to detect the surface tension of liquids. For liquids with good fluidity, such as water and organic solvents, traditional contact angle measurement methods can obtain relatively accurate results. However, for non-fluid glues, traditional methods have obvious limitations. After the non-fluid glue forms a droplet, due to its own high viscosity and low fluidity, the shape of the droplet is difficult to reach a stable state in a short time, which makes it difficult to accurately measure the contact angle. Moreover, the surface of the non-fluid glue may be uneven, resulting in large differences in the contact angle measurement values ​​at different locations, further affecting the accuracy of surface tension detection.

[0003] Due to the special properties of non-flowable glue, there is a lack of standardized testing procedures and technical specifications specifically for non-flowable glue.

[0004] In order to overcome the above-mentioned problems existing in existing detection methods when detecting the surface tension of glue with non-fluidity, the present invention proposes a surface tension testing method specifically for detecting glue with non-fluidity. Summary of the Invention

[0005] The purpose of this application is to provide a new technical solution for testing the surface tension of non-fluid glue.

[0006] The present invention provides a method for testing the surface tension of non-fluid glue. The method comprises the following steps: preparing a substrate, wherein a groove is provided on the surface of the substrate; Fill the groove with the glue to be tested and ensure that the surface of the glue to be tested is flush with the opening of the groove; Providing a liquid injection device, containing distilled water in the liquid injection device, and setting the dripping rate of the liquid injection device to a range of 0.2 μL to 0.5 μL per second; adding distilled water dropwise to at least three different locations on the surface of the glue by the liquid injection device to form at least three droplets; Calculate the contact angle of each droplet separately and obtain the contact angles of at least three target droplets; The surface tension of the non-flowable glue to be tested is determined based on the calculated contact angle of each target droplet.

[0007] Optionally, the environmental conditions of the test are set as follows: the temperature is in the range of 21° C. to 25° C., and the humidity is in the range of 40% RH to 60% RH.

[0008] Optionally, the substrate is made of a transparent material, and the shape of the groove is circular, square or rectangular.

[0009] Optionally, the depth of the groove set on the surface of the substrate is in the range of 0.5mm to 1.5mm; when the groove is circular, its diameter size range is 15mm to 25mm; when the groove is non-circular, its longest side length range is 15mm to 25mm.

[0010] Optionally, the injection device is a micro syringe or a dispensing valve.

[0011] Optionally, adding distilled water dropwise onto the surface of the glue through the liquid injection device specifically includes: The liquid injection device is kept in a vertical state during the dripping process to ensure that the distilled water droplets can accurately drip on the designated position on the glue surface.

[0012] Optionally, adding distilled water dropwise to at least three different locations on the surface of the glue by the liquid injection device specifically includes: The distance between two adjacent dripping positions is not less than 5mm.

[0013] Optionally, calculating the contact angle of each droplet separately to obtain the contact angles of at least three target droplets specifically includes: The contact angle of each droplet is calculated using image analysis technology; Based on the measured contact angle of each droplet, a deviation value of each droplet is calculated and determined; Determine the type of each droplet based on the deviation value of each droplet, where the droplet type includes target droplets and rejected droplets; Count the number of target droplets. If the number of target droplets is greater than or equal to 3, execute the subsequent steps. If the number of target droplets is less than 3, re-perform the droplet acquisition operation until the number of target droplets reaches the requirement of greater than or equal to 3.

[0014] Optionally, calculating and determining the deviation value of each droplet based on the measured contact angle of each droplet specifically includes: The arithmetic mean is determined from the measured values ​​of the contact angle of each droplet; The square of the deviation of each droplet was determined from the measured value of each contact angle and the arithmetic mean; For each droplet, if the square of its deviation is greater than a preset threshold, the droplet is determined to be a rejected droplet; if the square of its deviation is less than or equal to the preset threshold, the droplet is determined to be a target droplet.

[0015] Optionally, determining the surface tension of the non-flowable glue to be tested according to the calculated contact angle of each target droplet specifically includes: The contact angles of at least three target droplets were averaged; The surface energy of the glue to be tested is determined based on the average contact angle, surface tension of distilled water, polar component, and dispersion component; The surface energy of the glue to be tested is the surface tension of the glue to be tested.

[0016] One of the technical effects of this application is: The embodiment of the present application provides a surface tension test method for detecting non-fluid glue. This method prepares a substrate with grooves, fills the grooves with glue, and makes the surface flush with the groove opening, providing a stable testing environment for the glue; uses an injection device to drip distilled water at a specific speed to form droplets, and calculates the contact angle of each droplet separately, obtains the contact angles of at least three target droplets, and finally determines the surface tension of the non-fluid glue to be tested based on these contact angles. This method can effectively solve the problems of unstable droplets and inaccurate measurements of non-fluid glue during the detection process, and provides an accurate, reliable, and repeatable method for surface tension detection of non-fluid glue.

[0017] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0019] Figure 1 Shown is a flow chart of a surface tension testing method for detecting non-fluid glue provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0021] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0022] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0023] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0024] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0025] The present application embodiment provides a surface tension test method for detecting glue with non-fluidity. Figure 1 , the test method includes the following steps: S1: preparing a substrate, wherein a groove is provided on the surface of the substrate; S2: Fill the groove with the glue to be tested and ensure that the surface of the glue to be tested is flush with the opening of the groove; S3: providing a liquid injection device, filling the liquid injection device with distilled water, and setting the dripping rate of the liquid injection device to a range of 0.2 μL to 0.5 μL per second; S4: adding distilled water dropwise to at least three different locations on the surface of the glue through the liquid injection device to form at least three droplets; S5: Calculate the contact angle of each droplet and obtain the contact angles of at least three target droplets; S6: Determine the surface tension of the non-flowable glue to be tested based on the calculated contact angle of each target droplet.

[0026] The surface tension testing method for detecting non-fluid glue in the present application specifically indirectly tests the surface tension of non-fluid glue (creamy and non-fluid) by using a water drop angle method.

[0027] The embodiment of the present application provides a surface tension test method for detecting non-fluid glue. The method prepares a substrate with grooves, fills the grooves with glue and makes the surface flush with the groove opening, providing a stable testing environment for the glue; uses an injection device to drip distilled water at a specific speed to form droplets, and calculates the contact angle of each droplet separately, obtains the contact angles of at least three target droplets, and finally determines the surface tension of the non-fluid glue to be tested based on these contact angles. This method can effectively solve the problems of unstable droplets and inaccurate measurements of non-fluid glue during the detection process, and provides an accurate, reliable and repeatable method for surface tension detection of non-fluid glue.

[0028] Specifically, in step S1, a suitable material is selected to make a substrate, and a groove is machined into the substrate surface. The shape, size, and depth of the groove can be designed based on the actual testing requirements and the characteristics of the glue. For example, the groove can be rectangular, circular, or other regular shapes. Its size should be sufficient to accommodate a sufficient amount of glue to be tested, while ensuring that the surface of the glue is relatively flat after filling.

[0029] For example, the substrate can be made of glass. Specifically, the substrate can be a concave glass slide.

[0030] Substrates can be categorized as either disposable or non-disposable. Disposable substrates do not require surface cleaning during use; non-disposable substrates, on the other hand, require prior cleaning to ensure surface cleanliness meets test requirements. Regardless of the substrate type, the grooves must be filled with the glue to be tested to facilitate subsequent surface tension testing.

[0031] For glass substrates, deionized water, ethanol, or neutral detergent can generally be used. If there is oil on the glass surface, wipe it with ethanol to remove the oil, and then rinse it with deionized water.

[0032] The specific cleaning steps for glass substrates are as follows: first use a soft brush to remove large particles of dust on the surface, then gently wipe the glass surface with a wet sponge dipped in a neutral detergent solution, then rinse with plenty of deionized water to remove detergent residue, and finally blow dry with clean nitrogen or let it dry naturally.

[0033] In this step, the depth of the groove set on the surface of the substrate is in the range of 0.5mm to 1.5mm; when the groove is circular, its diameter size range is 15mm to 25mm, and when the groove is non-circular, its longest side length range is 15mm to 25mm.

[0034] In this embodiment, the groove depth is set within the range of 0.5mm to 1.5mm. A groove that is too shallow may not effectively contain the glue being tested, resulting in inaccurate test results. A groove that is too deep may increase manufacturing difficulty and cost, and may also affect overall performance due to uneven glue distribution within the groove. Preferably, the groove depth is less than 1mm, specifically 0.5mm, 0.6mm, 0.7mm, or 0.8mm.

[0035] In this embodiment, a suitable size range helps ensure uniform distribution of the glue within the groove, avoiding uneven distribution of the material due to oversize, or limiting the measurement to at least three different locations on the glue surface due to undersize. Preferably, the diameter or longest side of the groove ranges from 20 mm, 21 mm, 22 mm, 23 mm, or 24 mm.

[0036] In this step, the groove provides a fixed space for the non-flowing glue to be tested, preventing it from flowing and spreading during the test. This ensures the stability of the glue surface during the test, facilitating the subsequent accurate addition of distilled water and contact angle measurement. Furthermore, the volume of the groove allows for precise control of the amount of glue filled, ensuring a consistent amount for each test. This reduces interference with surface tension test results caused by varying glue amounts and improves the repeatability and accuracy of test results.

[0037] In step S2, use a suitable tool (such as a syringe or scraper) to slowly and evenly fill the prepared groove with the non-fluid glue to be tested. During the filling process, be careful to avoid introducing air bubbles. After filling, adjust the amount of glue or gently scrape it with a flattening tool (such as a glass slide) until the glue surface is level with the groove opening.

[0038] In this step, the glue surface is aligned with the groove opening to create a flat glue surface, which is crucial for the subsequent formation of distilled water droplets and accurate contact angle measurement. Furthermore, a flat surface can reduce irregular droplet shape and contact angle measurement errors caused by surface unevenness.

[0039] It is important to note that, given the curing and volatilization characteristics of adhesives, to ensure the accuracy and reliability of test results, testing should be carried out immediately after the adhesive to be tested is filled into the substrate groove. Furthermore, the entire process, from sample preparation to the completion of the test, must be strictly controlled within 5 minutes.

[0040] In step S3, a high-precision injection device, such as a microinjection pump or burette, is selected, cleaned, and filled with distilled water. By adjusting the device's parameters, the drip rate is set within a range of 0.2 μL to 0.5 μL per second. This drip rate range is determined experimentally based on the characteristics of the non-flowable glue and test requirements.

[0041] During this step, a suitable dripping rate can control the size and formation rate of the distilled water droplets. A dripping rate of 0.2μL to 0.5μL per second ensures that the droplets land on the glue surface in a relatively stable and controlled manner. This avoids excessive droplet size, splashing, or excessive impact with the glue surface due to a fast dripping rate, which could affect the contact angle measurement. It also prevents excessive test time due to a slow dripping rate, thereby improving test efficiency. Furthermore, a stable dripping rate helps form regularly shaped droplets, providing excellent conditions for accurate contact angle measurement, thereby improving the accuracy of surface tension testing.

[0042] Preferably, the dripping speed is set at 0.2 μL per second, or 0.3 μL per second, 0.4 μL per second, or 0.5 μL per second.

[0043] During the actual dripping process in step S3, the distilled water droplets fall primarily due to gravity from the outlet of the injection device. If the injection device is tilted, the droplets will be affected by the horizontal force during their fall, causing their trajectory to deviate and prevent them from landing accurately on the designated location on the glue surface. To ensure that the distilled water droplets land accurately on the designated location on the glue surface, the injection device is maintained in a vertical position during the dripping process.

[0044] In step S4, distilled water is dripped onto different locations on the glue surface by operating the liquid injection device. To obtain more accurate and reliable test results, it is necessary to select at least three different locations on the glue surface for dripping. These locations should be as evenly distributed as possible on the glue surface to avoid concentrating in one area.

[0045] During this step, the non-flowable glue surface may have localized inhomogeneities, such as compositional differences or surface roughness variations. By adding distilled water droplets at at least three different locations and measuring the contact angle, the overall surface condition of the glue can be comprehensively considered, eliminating the influence of local variations on the test results, and ensuring that the test results better reflect the glue's true surface tension.

[0046] In addition, the test data of multiple droplets can be statistically analyzed and compared. By calculating the average value, random errors can be reduced and the reliability and accuracy of the test results can be improved.

[0047] In step S4, the step of dripping distilled water onto at least three different positions on the surface of the glue by the liquid injection device specifically includes: a distance between two adjacent dripping positions is not less than 5 mm.

[0048] Specifically, when determining these drop locations, the spacing between adjacent drop locations must be no less than 5 mm. This spacing standard is set to ensure that each drop point is independent of each other, preventing the distilled water droplets from merging and diffusing due to too small a spacing, which could interfere with subsequent observations, measurements, or analyses based on drop locations, thereby ensuring the accuracy and reliability of experimental or test results.

[0049] In step S5, each droplet is observed and measured using a contact angle measuring instrument (e.g., an optical contact angle meter). The contact angle is the angle between the tangent line of the gas-liquid interface drawn through the intersection of the gas, liquid, and solid phases and the solid-liquid boundary line. The contact angle of each droplet is calculated using the instrument's built-in software or specialized image processing methods, and the contact angle data for at least three target droplets are recorded.

[0050] In this step, the contact angle is an important parameter reflecting the interaction between the liquid and the solid surface. By accurately calculating the contact angle of each droplet, the wettability and interaction between the distilled water droplet and the non-flowing glue surface can be quantified, providing key data for the subsequent determination of the surface tension of the glue.

[0051] In this step, contact angle data of at least three target droplets are obtained, which provides sufficient samples for subsequent data processing and analysis and helps to perform more accurate statistical analysis and error assessment.

[0052] In the specific embodiment of step S5, in order to accurately obtain the contact angles of at least three target droplets to ensure the reliability and effectiveness of subsequent analysis, the process includes four sub-steps (S51 to S54): S51: Calculate the contact angle of each droplet using image analysis technology; S52: Based on the measured contact angle of each droplet, calculating and determining the deviation value of each droplet; S53: determining the type of each droplet according to the deviation value of each droplet, where the droplet types include target droplets and rejected droplets; S54: Count the number of target droplets. If the number of target droplets is greater than or equal to 3, execute the subsequent steps (step S6). If the number of target droplets is less than 3, perform the droplet acquisition operation again (step S4) until the number of target droplets reaches the requirement of being greater than or equal to 3.

[0053] In step S51, image analysis technology is used to capture the droplet on the glue surface using high-precision imaging equipment (such as a high-speed camera or microscope) to obtain a clear and accurate image of the droplet. Specialized image analysis software, equipped with powerful image processing and geometric calculation capabilities, is then used to pre-process the droplet image (e.g., denoising and contrast enhancement) to highlight the droplet's outline. Next, a specific algorithm is used to identify the point of contact between the droplet and the glue surface, and the angle between the tangent line of the droplet at that point and the glue surface is measured. This angle is the droplet's contact angle. In this way, the contact angle of each droplet can be calculated sequentially.

[0054] In step S52, based on the measured contact angle of each droplet, calculating and determining the deviation value of each droplet specifically includes: S521: determining an arithmetic mean value based on the measured values ​​of the contact angle of each droplet; S522: determining the square of the deviation of each droplet based on the measured value of each contact angle and the arithmetic mean; S523: For each droplet, if the square of its deviation is greater than a preset threshold, the droplet is determined to be a rejected droplet; if the square of its deviation is less than or equal to the preset threshold, the droplet is determined to be a target droplet.

[0055] In step S521, the arithmetic mean is a common statistic used to describe the trend in a set of data. Calculating the arithmetic mean of all droplet contact angle measurements provides a benchmark for evaluating how each droplet's contact angle measurement deviates from the overall trend in the dataset, helping us determine whether the individual droplet data is representative and reasonable.

[0056] Suppose that n contact angle measurements are taken for a set of droplets, resulting in values ​​θ1, θ2, ..., θn. According to the formula for calculating the arithmetic mean, the arithmetic mean of the contact angle measurements for this set of droplets can be calculated by adding all the measured values ​​and dividing by the number of measurements, n. For example, if the contact angle measurements for five droplets are 30°, 32°, 31°, 33°, and 30°, respectively, the arithmetic mean ɑ = (30 + 32 + 31 + 33 + 30) / 5 = 31.2°.

[0057] In step S522, the squared deviation amplifies the difference between each droplet's contact angle measurement and the arithmetic mean, more prominently reflecting the data's dispersion. By calculating the squared deviation, we can avoid the situation where positive and negative deviations cancel each other out, more accurately measuring the degree to which each droplet's data deviates from the overall data set's central trend, providing a more effective basis for subsequent target droplet screening.

[0058] For each droplet contact angle measurement value θi (i=1, 2, ..., n), the square of the deviation is calculated according to the formula di 2 =(θi-ɑ) 2 , first calculate the difference between the measured value and the arithmetic mean ɑ, then square the difference to get the square of the deviation of each droplet di 2 For example, for the contact angle measurement value of the first droplet in the above example, θ1=30°, the arithmetic mean ɑ=31.2°, then the square of its deviation d1 2 =(30−31.2) 2 =1.44. Calculate the square of the deviation of each droplet in turn to get a set of square deviation values ​​d1 2 , d2 2 ,...,dn 2 .

[0059] In step S523, a preset threshold is used to determine whether the droplet data is acceptable. By comparing the squared deviation of each droplet with the preset threshold, droplets whose contact angle measurements deviate significantly from the overall data set trend are screened out (rejected droplets), while droplets with relatively stable and reliable measurements (target droplets) are retained, ensuring high-quality and accurate data for subsequent analysis.

[0060] Specifically, a reasonable preset threshold value T is determined in advance based on factors such as experimental requirements, data distribution characteristics, and actual needs. The threshold value can be determined by statistical analysis of a large amount of experimental data, reference to relevant industry standards or empirical values, etc. Then, the square of the deviation di calculated for each droplet is 2 Compare with the preset threshold T. If di 2 >T, indicating that the contact angle measurement value of the droplet deviates greatly from the trend of the overall data set, there may be measurement errors, abnormal droplet state and other problems, and it is judged to be a droplet to be removed; if di 2 ≤T, indicating that the contact angle measurement value of the droplet is relatively stable and meets the experimental requirements, and it is determined to be the target droplet. For example, if the preset threshold T=2, the square deviation di of a droplet in the above example is 2 =1.5, since 1.5≤2, the droplet is determined to be the target droplet; if the square of the deviation of another droplet dj 2 =2.5, because 2.5>2, the droplet is determined to be a rejected droplet.

[0061] In step S53, by determining the type of droplets, droplets with stable and reliable contact angle measurement results are screened as target droplets, and droplets with abnormal measurement results are excluded (rejected droplets) to ensure that the data used in subsequent analysis are of high quality and accuracy.

[0062] In step S54, the subsequent analysis (step S6) is ensured to be based on a sufficient number of target droplet data to improve the accuracy and reliability of the analysis results. This is because data from at least three target droplets is required to perform effective statistical analysis, such as calculating the mean and standard deviation, to more fully understand the characteristics of the glue surface.

[0063] In this step, the target droplets identified in step S53 are counted. If the target droplet count is greater than or equal to 3, the data requirements for subsequent analysis have been met, and the subsequent steps (step S6) can be smoothly executed for more in-depth analysis and processing. If the target droplet count is less than 3, the current data volume is insufficient for accurate analysis, and the droplet acquisition operation (step S4) must be repeated. This involves adding droplets to the glue surface using the injection device again, and then repeating steps S51-S53 until the target droplet count reaches the required number of 3 or greater. This ensures data integrity and accuracy throughout the entire experiment or analysis process.

[0064] In step S6, using a known formula for the relationship between contact angle and surface tension (such as the Young equation, the Young-Laplace equation, or the Eos algorithm), combined with the surface tension parameter of distilled water (a known value at a specific temperature), the calculated contact angle of each target droplet is substituted into the formula for calculation to ultimately determine the surface tension of the non-flowing glue to be tested.

[0065] By obtaining accurate contact angle data through the above steps and applying the formula for calculation, the surface tension of the non-flowable glue to be tested can be accurately determined, providing an important basis for the performance evaluation, quality control and application of the glue.

[0066] The surface tension of the glue is determined by the method provided in the embodiments of the present application. Understanding the surface tension of the glue helps to optimize the application process of the glue in different fields. For example, in the processes of coating, bonding, sealing, etc., the process parameters can be adjusted according to the size of the surface tension to improve the quality and performance of the product.

[0067] In step S6, determining the surface tension of the non-fluid glue to be tested based on the calculated contact angle of each target droplet specifically includes: S61: averaging the contact angles of at least three target droplets; S62: Determine the surface energy of the glue to be tested based on the average contact angle, the surface tension of distilled water, the polar component, and the dispersion component; S63: The surface energy of the glue to be tested is the surface tension of the glue to be tested.

[0068] In step S61, the contact angle measurement of a single droplet may be subject to certain errors, influenced by various factors, such as irregular droplet shape, precision limitations of the measuring instrument, and slight fluctuations in environmental conditions. Taking the average of the contact angles of at least three target droplets can effectively reduce these random errors, improve the accuracy and reliability of the contact angle data, and make subsequent calculations and analyses based on this average more scientific and representative.

[0069] In step S62, surface energy is an important physical quantity that measures a material's surface properties and is closely related to its wettability, adhesion, and other properties. By using the known average contact angle and relevant parameters of distilled water (surface tension, polar component, and dispersion component), along with a specific theoretical model and calculation formula, the surface energy of the glue being tested can be accurately calculated, providing a deeper understanding of its surface characteristics.

[0070] For example, when using the Eos method, the surface tension, polar component, and dispersion component of water are fixed values. By inputting the average value of the tested contact angle, the surface energy of the glue can be calculated, which is the surface tension of the glue.

[0071] According to an embodiment of the present application, the environmental conditions of the test are set as follows: the temperature is in the range of 21° C. to 25° C., and the humidity is in the range of 40% RH to 60% RH.

[0072] During the implementation of this application, to ensure the accuracy and reliability of the test results, the test environment conditions were limited. Specifically, the test environment temperature was limited to the range of 21°C (inclusive) to 25°C (inclusive). This effectively prevents adverse effects on the glue being tested due to excessively high or low temperatures, ensuring that the test is conducted under relatively stable and appropriate temperature conditions.

[0073] The humidity of the test environment is also controlled within a range of 40% RH (inclusive) to 60% RH (inclusive). This humidity range is designed to prevent interference with test results caused by excessive or insufficient humidity, providing a stable environment with suitable humidity for testing. This minimizes the impact of environmental factors on the accuracy of test data and ensures that the data obtained through testing truly and accurately reflects the surface tension characteristics of the glue.

[0074] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0075] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above examples may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A surface tension test method for detecting non-fluid glue, characterized in that: The following steps are involved: preparing a substrate, wherein a groove is provided on the surface of the substrate; Fill the groove with the glue to be tested and ensure that the surface of the glue to be tested is flush with the opening of the groove; Providing a liquid injection device, containing distilled water in the liquid injection device, and setting the dripping rate of the liquid injection device to a range of 0.2 μL to 0.5 μL per second; adding distilled water dropwise to at least three different locations on the surface of the glue by the liquid injection device to form at least three droplets; Calculate the contact angle of each droplet separately and obtain the contact angles of at least three target droplets; The surface tension of the non-flowable glue to be tested is determined based on the calculated contact angle of each target droplet.

2. The method for testing the surface tension of glue according to claim 1, characterized in that: The environmental conditions of the test were set as follows: the temperature was in the range of 21° C. to 25° C., and the humidity was in the range of 40% RH to 60% RH.

3. The method for testing the surface tension of glue according to claim 1, characterized in that: The substrate is made of a transparent material, and the shape of the groove is one of circular, square or rectangular.

4. The method for testing the surface tension of glue according to claim 1 or 2, characterized in that: The depth of the groove set on the surface of the substrate is in the range of 0.5mm to 1.5mm; when the groove is circular, its diameter ranges from 15mm to 25mm; when the groove is non-circular, its longest side length ranges from 15mm to 25mm.

5. The method for testing the surface tension of glue according to claim 1, characterized in that: The liquid injection device is a micro syringe or a dispensing valve.

6. The method for testing the surface tension of glue according to claim 1 or 5, characterized in that: Adding distilled water dropwise onto the surface of the glue by the liquid injection device specifically includes: The liquid injection device is kept in a vertical state during the dripping process to ensure that the distilled water droplets can accurately drip on the designated position on the glue surface.

7. The method for testing the surface tension of glue according to claim 1, characterized in that: The step of adding distilled water dropwise to at least three different locations on the surface of the glue by the liquid injection device specifically includes: The distance between two adjacent dripping positions is not less than 5mm.

8. The method for testing the surface tension of glue according to claim 1, characterized in that: Calculating the contact angle of each droplet separately and obtaining the contact angles of at least three target droplets specifically includes: The contact angle of each droplet is calculated using image analysis technology; Based on the measured contact angle of each droplet, a deviation value of each droplet is calculated and determined; Determine the type of each droplet based on the deviation value of each droplet, where the droplet type includes target droplets and rejected droplets; Count the number of target droplets. If the number of target droplets is greater than or equal to 3, execute the subsequent steps. If the number of target droplets is less than 3, re-perform the droplet acquisition operation until the number of target droplets reaches the requirement of greater than or equal to 3.

9. The method for testing the surface tension of glue according to claim 8, characterized in that: Based on the measured contact angle of each droplet, the deviation value of each droplet is calculated and determined, specifically including: The arithmetic mean is determined from the measured values ​​of the contact angle of each droplet; The square of the deviation of each droplet was determined from the measured value of each contact angle and the arithmetic mean; For each droplet, if the square of its deviation is greater than a preset threshold, the droplet is determined to be a rejected droplet; if the square of its deviation is less than or equal to the preset threshold, the droplet is determined to be a target droplet.

10. The method for testing the surface tension of glue according to claim 1, characterized in that: Based on the calculated contact angle of each target droplet, the surface tension of the non-flowable glue to be tested is determined by: The contact angles of at least three target droplets were averaged; The surface energy of the glue to be tested is determined based on the average contact angle, surface tension of distilled water, polar component, and dispersion component; The surface energy of the glue to be tested is the surface tension of the glue to be tested.

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