A method for testing the wicking height of polyester filaments

Abstract

The application belongs to the technical field of testing, and discloses a polyester filament wicking height testing method, which is characterized in that: at 25 DEG C, after the polyester filament is vertically placed, the lower end of the polyester filament is immersed in a NaOH aqueous solution with a concentration of 10 ‑5 0.1 mol / L and a temperature of 25 DEG C, after waiting for 60 min, the state of the polyester filament is kept unchanged, an acid-base indicator solution is applied to the polyester filament, and the distance between the highest discoloration point on the polyester filament and the liquid level of the NaOH aqueous solution is measured, so that the wicking height of the polyester filament is obtained. The surface tension and viscosity of the NaOH aqueous solution of the application are close to those of pure water, so the climbing heights of the two are close within the same time, and the height difference can be almost ignored, so that the waterproof effect of the polyester filament can be more accurately obtained.

Description

Technical Field

[0001] This invention belongs to the field of testing technology and relates to a method for testing the wicking height of polyester filament. Background Technology

[0002] When polyester filament is used in waterproofing applications, it needs to have anti-wicking capabilities. The anti-wicking capability is mainly tested by measuring the wicking height of the polyester filament; the lower the wicking height, the better the waterproofing effect. According to section 6.2.6 of the standard Q / 320584NPA019-2025 "Anti-wicking Polyester Industrial Filament," the wicking height is tested by adding a certain proportion of ink and water to a storage tank, immersing one end of the polyester filament to be tested in the tank, and fixing the other end to a sample holder. The wicking height is observed after 60 minutes.

[0003] The wicking height is primarily measured visually by observing the height of the colored sections on the polyester filament. However, actual testing revealed that the color gradually lightens from bottom to top, with the top section being very pale. This indicates that water rises faster than ink, and the wicking height observed over 60 minutes cannot accurately reflect the water absorption height. Since polyester filament is used in products designed to repel water, not ink, inaccurate test results can mislead buyers when selecting products, resulting in ineffective waterproofing.

[0004] Therefore, it is of great significance to study a method for testing the wicking height of polyester filaments in order to measure the wicking height more accurately. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the prior art and to provide a method for testing the wicking height of polyester filament.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for testing the wicking height of polyester filament involves placing the polyester filament vertically at 25°C and immersing its lower end in a solution with a concentration of 10... -5 In a NaOH aqueous solution of ~0.1 mol / L at 25℃, after waiting for 60 minutes, while keeping the polyester filament unchanged, apply an acid-base indicator solution (the water continues to rise during the application of the indicator solution, but the rise height during this time is negligible compared to the rise height within 60 minutes). Measure the distance between the highest color change point on the polyester filament and the surface of the NaOH aqueous solution to obtain the wicking height of the polyester filament.

[0008] Liquids climb up polyester filaments through capillary action. According to Zhulin's law, the surface tension of the liquid affects the strength of capillary action, thus affecting the wicking height.

[0009] The formula for Julling's Law is: h = (2γ cosθ) / (ρ gr);

[0010] Where h is the height by which the liquid level rises or falls in the capillary; γ is the surface tension; θ is the contact angle (measuring the liquid's ability to wet the capillary wall); ρ is the liquid density; g is the acceleration due to gravity; and r is the capillary radius.

[0011] Furthermore, when θ, ρ, g, and r are the same, surface tension determines the liquid's climbing height;

[0012] Reference 1 (CRC Handbook of Chemistry and Physics [M]. 2019.) states that the surface tension of water at 25℃ is approximately 71.97 mN / m, and the concentration is 10. -5 The surface tension of a 0.1 mol / L NaOH aqueous solution is approximately 71.97-72.17 mN / m. Therefore, the concentration used in this application is 10. -5 The surface tension of a ~0.1 mol / L NaOH aqueous solution is close to that of water, meaning that the climbing height of the NaOH aqueous solution in this application is close to that of water.

[0013] According to the Washburn equation, the square of the elevation gain is inversely proportional to the fluid viscosity. This indicates that, within the same time interval, lower viscosity results in better fluidity and a faster elevation gain. Furthermore, Poiseuille's law further proves that, under the same driving pressure, lower fluid viscosity leads to a larger volumetric flow rate, meaning the fluid flows faster. The viscosity of water at 25°C is 0.89 mPa·s, and its concentration is 10... -5 The viscosity of a NaOH aqueous solution with a concentration of ~0.1 mol / L and a temperature of 25°C is approximately 0.89~0.905 mPa·s, and it feels almost as thin as water. Therefore, the climbing rate of the NaOH aqueous solution in this application is close to that of water.

[0014] Therefore, the surface tension and viscosity of the NaOH aqueous solution in this application are basically the same as those of pure water. Thus, the heights they climb in the same amount of time are similar, and the height difference is almost negligible.

[0015] As a preferred technical solution:

[0016] As described above, in a method for testing the wicking height of polyester filament, the acid-base indicator solution is applied by spraying.

[0017] In the above-described method for testing the wicking height of polyester filament, the acid-base indicator solution is phenolphthalein solution.

[0018] In the above-described method for testing the wicking height of polyester filament, the phenolphthalein solution is a phenolphthalein ethanol solution.

[0019] As described above, in a method for testing the wicking height of polyester filament, a pressure block is tied to the lower end of the polyester filament, and the upper end is fixed to a test bracket.

[0020] As described above, in a method for testing the wicking height of polyester filament, the polyester filament is dried before immersion to remove moisture.

[0021] The above-described method for testing the wicking height of polyester filament involves a drying temperature of 150°C and a drying time of 5 minutes.

[0022] The method for testing the wicking height of polyester filament as described above requires a polyester filament length ≥ 15cm.

[0023] The above-described method for testing the wicking height of polyester filament uses a measuring ruler to measure the distance between the highest discoloration point on the polyester filament and the surface of the NaOH aqueous solution.

[0024] Beneficial effects:

[0025] (1) The surface tension and viscosity of the NaOH aqueous solution of the present invention are close to those of pure water. Therefore, the heights of the two are similar in the same time period, and the height difference is almost negligible, thus obtaining the waterproof effect of polyester filament more accurately.

[0026] (2) By controlling the upper limit of the concentration of NaOH aqueous solution, the maximum value of its viscosity and surface tension can be controlled, so that it avoids a large difference from water. By controlling the lower limit, the color depth of NaOH after reacting with phenolphthalein can be controlled, thereby avoiding the color being too light to be seen. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0028] The manufacturers and brands mentioned in the following embodiments are merely examples. The core of this invention lies in the technical solution itself, and it is not intended to limit specific manufacturers or brands. Products from other manufacturers and brands that meet the technical requirements and performance indicators specified in this invention can also meet the application requirements of this invention and are all feasible choices.

[0029] The surface tension test method is as follows: refer to GB / T 22237-2008 "Determination of surface tension of surfactants"; the ambient temperature is 25℃ and the temperature of the solution being tested is 25℃.

[0030] Viscosity test method: Refer to GB / T 10247-2008 "Viscosity Measurement Method"; wherein, the ambient temperature is 25℃ and the temperature of the solution being tested is 25℃.

[0031] A method for testing the wicking height of polyester filament, the specific process of which is as follows:

[0032] First, dry polyester filaments with a length ≥15cm at a drying temperature of 150℃ for 5 minutes. Then, at 25℃, place the polyester filaments vertically, fix the upper end to the test bracket, and immerse the lower end, which is bound with a pressure block, in a solution with a concentration of 10%. -5 In a NaOH aqueous solution of ~0.1 mol / L at 25℃, after waiting for 60 minutes, while keeping the polyester filament unchanged, apply phenolphthalein ethanol solution to it by spraying. The wicking height of the polyester filament is obtained by measuring the distance between the highest color change point on the polyester filament and the surface of the NaOH aqueous solution.

[0033] The following specific embodiments illustrate the method for testing the wicking height of polyester filament according to the present invention:

[0034] Example 1

[0035] A method for testing the wicking height of polyester filament, comprising the following steps:

[0036] (1) First, dry a 25cm long polyester filament (specification 1440dtex / 192f) at 150℃ for 5min. Then, at 25℃, place the polyester filament vertically, fix its upper end to the test bracket, and immerse the lower end, which is bound with a pressure block (applying a tension of 0.05cN / dtex to the polyester filament), in a solution with a concentration of 10. -3 The polyester filament was placed in a NaOH aqueous solution (viscosity: 0.89 mPa·s; surface tension: 71.97 mN / m) at 25 °C for 60 min, while maintaining the state of the polyester filament.

[0037] (2) After applying phenolphthalein ethanol solution to polyester filament by spraying (it turns from colorless to red when it comes into contact with NaOH), the distance between the highest color change point on the polyester filament and the surface of the NaOH aqueous solution is measured with a ruler to obtain the wicking height of the polyester filament. Then, polyester filaments of the same length and specifications are selected and the test is repeated. The wicking heights are 3.8cm and 3.5cm respectively. Finally, the average value is calculated to be 3.7cm.

[0038] To verify the accuracy of the above test method, different test solutions were used for measurement, as detailed below:

[0039] Pure water test group: The test method is basically the same as in Example 1, except that before the polyester filament test, the NaOH aqueous solution was replaced with pure water. After the test, anhydrous copper sulfate powder was applied to the surface of the industrial polyester filament. The wicking heights were 4.1cm and 3.5cm, respectively, and the average value was 3.8cm.

[0040] Non-carbon ink test group: The test method is basically the same as in Example 1, except that the NaOH aqueous solution used in the test is replaced with non-carbon ink. Finally, a polyester filament is tested repeatedly, and the wicking heights are 3.0cm and 3.1cm respectively. The average value is 3.1cm.

[0041] By comparing the data obtained above, it can be seen that the wicking height measured by the test method of the present invention is closer to that of pure water, and the measurement is more accurate. Although the pure water test group can also measure the data of polyester filament, the anhydrous copper sulfate powder attached to the polyester filament turns light blue when it comes into contact with water, which will result in insufficient observation clarity.

[0042] Comparative Example 1

[0043] A method for testing the wicking height of polyester filament is basically the same as in Example 1, except that the concentration of the NaOH aqueous solution is 5 × 10⁻⁶. -7 mol / L.

[0044] The wick height could not be detected because the concentration was less than 10. -5 The pH value of the mol / L NaOH aqueous solution is lower than the color change range of phenolphthalein, so no color will appear after contact with the phenolphthalein solution.

[0045] Comparative Example 2

[0046] A method for testing the wicking height of polyester filament is basically the same as in Example 1, except that the concentration of the NaOH aqueous solution is 2 mol / L.

[0047] The measured wicking heights of the polyester filament were 4.7 cm and 5.2 cm, with the average value being 4.95 cm. Compared to the pure water test in Example 1, the wicking height deviation was larger. This is because the surface tension of the 2 mol / L NaOH aqueous solution was 76.1 mN / m, and its viscosity was 1.396 mPa·s, while the surface tension of water was 71.97 mN / m, and its viscosity was 0.89 mPa·s. The surface tension and viscosity of the two solutions differed significantly.

[0048] Example 2

[0049] A method for testing the wicking height of polyester filament, comprising the following steps:

[0050] (1) First, dry a 25cm long polyester filament (4400dtex / 488f) at 150℃ for 5min. Then, at 25℃, place the polyester filament vertically, fix its upper end to the test bracket, and immerse the lower end, which is tied with a pressure block (applying a tension of 0.05cN / dtex to the polyester filament), in a solution with a concentration of 10. -3 The polyester filament was placed in a NaOH aqueous solution (viscosity: 0.89 mPa·s; surface tension: 71.97 mN / m) at 25 °C for 60 min, while maintaining the state of the polyester filament.

[0051] (2) After applying phenolphthalein ethanol solution to polyester filament by spraying (it turns from colorless to red when it comes into contact with NaOH), the distance between the highest color change point on the polyester filament and the surface of the NaOH aqueous solution is measured with a ruler to obtain the wicking height of the polyester filament. Then, polyester filaments of the same length and specifications are selected and the test is repeated. The wicking heights are 19.1cm and 19.5cm respectively. Finally, the average value is 19.3cm.

[0052] To verify the accuracy of the above test method, different test solutions were used for measurement, as detailed below:

[0053] Pure water test group: The test method is basically the same as in Example 2, except that: before the polyester filament test, the NaOH aqueous solution was replaced with pure water. After the test, anhydrous copper sulfate powder was applied to the surface of the industrial polyester filament. The wicking heights were 19cm and 19.4cm respectively, and the average value was 19.2cm.

[0054] Non-carbon ink test group: The test method is basically the same as in Example 2, except that the NaOH aqueous solution used in the test is replaced with non-carbon ink. Finally, a polyester filament is tested repeatedly, and the wicking heights are 18.4cm and 19cm respectively. The average value is 18.7cm.

[0055] Example 3

[0056] A method for testing the wicking height of polyester filament, comprising the following steps:

[0057] (1) First, dry a 25cm long polyester filament (specification 1100dtex / 144f) at 150℃ for 5min. Then, at 25℃, place the polyester filament vertically, fix its upper end to the test bracket, and immerse the lower end, which is tied with a pressure block (applying a tension of 0.05cN / dtex to the polyester filament), in a solution with a concentration of 10. -4The polyester filament was placed in a NaOH aqueous solution (viscosity 0.89 mPa·s, surface tension 71.97 mN / m, the viscosity and surface tension here are the same as in Examples 1-2 because the deviation is very small, and the values ​​are rounded to two decimal places to obtain the same value) at a temperature of 25℃ for 60 minutes, and the state of the polyester filament remained unchanged.

[0058] (2) After applying phenolphthalein ethanol solution to polyester filament by spraying (it turns from colorless to red when it comes into contact with NaOH), the distance between the highest color change point on the polyester filament and the surface of the NaOH aqueous solution is measured with a ruler to obtain the wicking height of the polyester filament. Then, polyester filaments of the same length and specifications are selected and the test is repeated. The wicking heights are 16.5cm and 16.5cm respectively. Finally, the average value is 16.5cm.

[0059] To verify the accuracy of the above test method, different test solutions were used for measurement, as detailed below:

[0060] Pure water test group: The test method is basically the same as in Example 3, except that: before the polyester filament test, the NaOH aqueous solution was replaced with pure water. After the test, anhydrous copper sulfate powder was applied to the surface of the industrial polyester filament. The wicking heights were 16.3cm and 16.7cm, respectively, and the average value was 16.5cm.

[0061] Non-carbon ink test group: The test method is basically the same as in Example 3, except that the NaOH aqueous solution used in the test is replaced with non-carbon ink. Finally, a polyester filament is tested repeatedly, and the wicking heights are 15.6cm and 15cm respectively. The average value is 15.3cm.

Claims

1. A method for testing the wicking height of polyester filament, characterized in that, At 25°C, polyester filaments are placed vertically, and their lower ends are immersed in a solution with a concentration of 10. -5 In a NaOH aqueous solution of ~0.1mol / L at 25℃, after waiting for 60 minutes, while keeping the polyester filament in the same state, apply an acid-base indicator solution to it, and measure the distance between the highest color change point on the polyester filament and the surface of the NaOH aqueous solution to obtain the wicking height of the polyester filament.

2. The method for testing the wicking height of polyester filament according to claim 1, characterized in that, The acid-base indicator solution is applied by spraying.

3. The method for testing the wicking height of polyester filament according to claim 2, characterized in that, The acid-base indicator solution is phenolphthalein solution.

4. The method for testing the wicking height of polyester filament according to claim 3, characterized in that, The phenolphthalein solution is an ethanolic solution of phenolphthalein.

5. The method for testing the wicking height of polyester filament according to claim 1, characterized in that, The lower end of the polyester filament is tied with a pressure block, and the upper end is fixed to the test bracket.

6. The method for testing the wicking height of polyester filament according to claim 1, characterized in that, Before immersion, the polyester filaments are dried.

7. The method for testing the wicking height of polyester filament according to claim 6, characterized in that, The drying temperature is 150℃ and the drying time is 5 minutes.

8. The method for testing the wicking height of polyester filament according to claim 1, characterized in that, The length of the polyester filament is ≥15cm.

9. The method for testing the wicking height of polyester filament according to claim 1, characterized in that, A ruler was used to measure the distance between the highest discoloration point on the polyester filament and the surface of the NaOH aqueous solution.