Solution for testing the antioxidation of polyethylene pipes and its preparation method and application

Abstract

The application relates to a polyethylene pipe antioxidant test solution in the technical field of high polymer materials, and a preparation method and application thereof. The polyethylene pipe antioxidant test solution comprises the following components in parts by weight: water: 100 parts; acid: 1-5 parts; alkali: 0.2-4 parts; tea polyphenol: 0.1-1 part. The test solution can be used for a polyethylene pipe antioxidant test solution. The application uses tea polyphenol as a test reagent, can effectively simulate a real drinking water disinfectant, is safe and environment-friendly, shortens an evaluation period, obtains reliable test data, and is worth popularization and application.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a solution for testing the antioxidant properties of polyethylene pipes, its preparation method, and its application. Background Technology

[0002] When polyethylene pipes are used to transport drinking water for extended periods, the presence of chlorine disinfectants in the water causes oxidation of the polyethylene pipes, leading to premature failure. The pipes are damaged before reaching their expected lifespan, affecting public health and safety in water supply. Therefore, the antioxidant properties of special polyethylene pipe materials have received great attention from pipe manufacturers and users.

[0003] To evaluate the antioxidant properties of polyethylene pipe materials in water, an antioxidant test method for pipe materials was developed. The evaluation method requires the preparation of a test solution simulating disinfectant in drinking water. The preparation of the test solution is crucial to improving the reliability and effectiveness of the evaluation method.

[0004] Therefore, developing a test solution that can shorten the evaluation cycle, is safe and environmentally friendly, and closely resembles a real disinfectant is crucial for the evaluation and promotion of the evaluation method for the antioxidant properties of polyethylene pipe materials. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention proposes a solution for testing the antioxidant properties of polyethylene pipes. Specifically, it relates to a solution for testing the antioxidant properties of polyethylene pipes, its preparation method, and its application.

[0006] The purpose of this invention is to provide a test solution for the antioxidant properties of polyethylene pipes. This test solution can be used for testing the antioxidant properties of polyethylene pipes. This invention uses tea polyphenols as a test reagent, which can effectively simulate real drinking water disinfectants, is safe and environmentally friendly, shortens the evaluation cycle, and obtains reliable test data.

[0007] One objective of this invention is to provide a solution for testing the antioxidant properties of polyethylene pipes, specifically comprising the following components in parts by weight:

[0008] Water: 100 parts;

[0009] Acid: 1-5 parts, preferably 1.5-3.5 parts;

[0010] Alkali: 0.2–4 parts, preferably 0.3–2 parts;

[0011] Tea polyphenols (TP): 0.1 to 1 part, preferably 0.3 to 1 part.

[0012] Specifically, based on 100 parts by weight of water,

[0013] The amount of acid used can be 1 to 5 parts. The specific number of parts can be 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or any value between the above values ​​or any two of the above values. For example, it can be a value range of 1.5 to 3, 1.5 to 2.5, etc.

[0014] The amount of alkali used can be 0.2 to 4 parts. The specific part value can be selected from 0.2, 0.3, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4 or any value between the above values ​​or any two of the above values. For example, it can be a value range of 0.5 to 1.5, 0.5 to 1, etc.

[0015] The dosage of tea polyphenols can be 0.1 to 1 part. The specific part value can be selected from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or any value between the above values ​​or any two of the above values. For example, it can be a value range of 0.2 to 0.8, 0.5 to 0.8, etc.

[0016] Preferably,

[0017] The water may be deionized water.

[0018] The acid may be hydrochloric acid; preferably, the mass fraction concentration of the hydrochloric acid is 37%.

[0019] The alkali may be sodium hydroxide.

[0020] Tea polyphenols (TP) are a major class of chemical substances in tea, composed of catechins, flavonoids, phenolic acids, and condensed phenolic acids. Catechins constitute the majority of tea polyphenols, accounting for approximately 70%–80%. Their structure includes at least three ring cores, and they are derivatives of 2-phenylbenzopyran, currently mainly used in food processing. In practice, the inventors of this application have discovered that while tea polyphenols cannot yet replace existing drinking water disinfectants for water disinfection, they have shown that in antioxidant tests of polyethylene pipes, tea polyphenols can disrupt the antioxidant system of polyethylene pipe materials, causing premature pipe failure. This effectively simulates real drinking water disinfectants and meets the needs of accelerated antioxidant testing, particularly for polyethylene pipes.

[0021]

[0022] R1 can be levo-epigaloside or levo-epigalocatechin; R2 can be levo-epigalocatechin.

[0023] The second objective of this invention is to provide a method for preparing the solution for testing the antioxidant properties of polyethylene pipes, which may include the following steps:

[0024] The acid is added to water, then the alkali is added to make the solution acidic, then tea polyphenols are added, and the mixture is heated to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

[0025] Specifically, the preparation method may include the following steps:

[0026] (1) Add the acid to water, mix well, and then add the alkali to make the solution pH acidic;

[0027] (2) Add tea polyphenols to the solution prepared in step (1) and stir;

[0028] (3) Heat the solution obtained in step (2) to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

[0029] in,

[0030] In step (1), the pH value of the solution can be between 3 and 6; and / or,

[0031] In step (2), the stirring time can be greater than 5 minutes.

[0032] In step (3), the heating temperature can be 37℃~43℃, preferably 39~41℃.

[0033] Specifically, the preparation method of the solution for the antioxidant test of polyethylene pipes may include the following steps:

[0034] HCl solution is added to water, then NaOH solid is added to make the pH of the solution acidic, then tea polyphenols are added, and the mixture is heated to obtain the test solution for polyethylene pipes.

[0035] More specifically,

[0036] The preparation method of the solution for testing the antioxidant properties of polyethylene pipes may include the following steps:

[0037] (1) Add hydrochloric acid to water, mix well, and then add NaOH to make the solution acidic, with the pH between 3 and 6.

[0038] (2) Add tea polyphenols to the solution prepared in step (1) and stir with a stirrer for more than 5 minutes;

[0039] (3) Heat the solution obtained in step (2) to 40±1℃ to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

[0040] In practice,

[0041] The preparation method of the solution for testing the antioxidant properties of polyethylene pipes may include the following steps:

[0042] (1) Add 1 to 5 parts by weight of hydrochloric acid (concentration of 37%) to 100 parts by weight of deionized water, mix well, then add 0.5 to 4 parts by weight of NaOH solid, mix well, so that the pH of the solution is acidic, between pH 3 and 6.

[0043] (2) Add 0.1 to 1 part by weight of tea polyphenols to the solution prepared in step (1), and stir with a stirrer for more than 5 minutes to ensure that the tea polyphenols are completely dissolved.

[0044] (3) Heat the solution obtained in step (2) to 40±1℃ to obtain the solution for testing the antioxidant properties of polyethylene pipes.

[0045] A third objective of this invention is to provide a solution for testing the antioxidant properties of polyethylene pipes prepared by the aforementioned method.

[0046] The fourth objective of this invention is to provide the application of the polyethylene pipe antioxidant test solution described in the first objective of this invention or the polyethylene pipe antioxidant test solution obtained by the preparation method described in the second objective of this invention, preferably in the antioxidant test of polyethylene pipes for drinking water, and more preferably in the antioxidant evaluation of polyethylene pipes for drinking water.

[0047] The antioxidant test solution for polyethylene pipes described in this invention can effectively simulate real drinking water disinfectants in accelerated testing. It is safe, environmentally friendly, and ensures the personal safety of operators. It has low requirements for experimental conditions, does not produce toxic gas emissions, and does not require the configuration of toxic gas treatment devices. It meets SHE requirements and can shorten the antioxidant evaluation cycle of polyethylene pipe materials, obtain reliable test data, and help ensure the public safety of drinking water transmission pipelines. Detailed Implementation

[0048] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0049] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0050] Source of raw materials

[0051] Tea polyphenols, manufactured by Henan Jucan Bioengineering Co., Ltd., CAS number 84650-60-2.

[0052] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0053] Test methods

[0054] (1) The oxidation induction time (OIT) was determined according to GB / T 19466.6-2009 standard, and the test temperature was 200℃, in order to evaluate the oxidizing properties of different test solutions on polyethylene pipes.

[0055] (2) The elongation at break test shall be conducted in accordance with GB / T 8804.3-2003 standard.

[0056] Example 1

[0057] Prepare a solution for testing the antioxidant properties of polyethylene pipes.

[0058] The preparation method includes the following steps:

[0059] (1) Weigh out the deionized water, HCl solution (concentration of 37%), NaOH solid and tea polyphenol solid according to the amounts specified in Table 1, and set aside.

[0060] (2) Add HCl solution to deionized water, mix well, and then add NaOH solid to make the pH of the solution between 3 and 6;

[0061] (3) Add the solid tea polyphenols to the solution prepared in step (2) and stir for 10 min;

[0062] (4) Heat the solution obtained in step (3) to 39°C to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

[0063] The temperature of the solution used for the antioxidant test of the polyethylene pipe was raised to 40°C. Three identical DN63 polyethylene pipes (Shanghai Petrochemical YGH041T PE100) were prepared as test samples. Two of the DN63 polyethylene pipes were immersed in the solution. After 500 hours and 1000 hours, the samples were taken out to determine the oxidation induction time (OIT) (test temperature 200°C) and the elongation at break. The test results are shown in Tables 2 and 3.

[0064] Table 1. Components (parts by mass) of the solutions in the examples and comparative examples

[0065] raw material Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Deionized water 100 100 100 100 100 HCl solution 2 2 2 0 0 NaOH solid 0.5 1 1 0 0 Tea polyphenol solids 0.5 0.5 0.8 0 0 Sodium hypochlorite solid 0 0 0 1 0

[0066] Example 2

[0067] Prepare a solution for testing the antioxidant properties of polyethylene pipes.

[0068] The preparation method includes the following steps:

[0069] (1) Weigh out the deionized water, HCl solution (concentration of 37%), NaOH solid and tea polyphenol solid according to the amounts specified in Table 1, and set aside.

[0070] (2) Add HCl solution to deionized water, mix well, and then add NaOH solid to make the pH of the solution between 3 and 6;

[0071] (3) Add the solid tea polyphenols to the solution prepared in step (2) and stir for 8 minutes;

[0072] (4) Heat the solution obtained in step (3) to 40°C to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

[0073] The temperature of the solution used for the antioxidant test of the polyethylene pipe was maintained at 40°C. Three samples of the same dn63 polyethylene pipe (Shanghai Petrochemical YGH041T PE100) as in Example 1 were prepared as test samples. Two of the dn63 polyethylene pipe samples were immersed in the solution. After 500 hours and 1000 hours, the samples were taken out for oxidation induction time (OIT) and elongation at break tests, respectively. The test results are shown in Tables 2 and 3.

[0074] Example 3

[0075] Prepare a solution for testing the antioxidant properties of polyethylene pipes.

[0076] The preparation method includes the following steps:

[0077] (1) Weigh out the deionized water, HCl solution (concentration of 37%), NaOH solid and tea polyphenol solid according to the amounts specified in Table 1, and set aside.

[0078] (2) Add HCl solution to deionized water, mix well, and then add NaOH solid to make the pH of the solution between 3 and 6;

[0079] (3) Add the solid tea polyphenols to the solution prepared in step (2) and stir for 12 min;

[0080] (4) Heat the solution obtained in step (3) to 39°C to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

[0081] The temperature of the polyethylene pipe oxidation test solution was raised to 40°C. Three identical dn63 polyethylene pipes (Shanghai Petrochemical YGH041T PE100) as in Example 1 were prepared as test samples. Two of the dn63 polyethylene pipes were immersed in the solution. After 500 hours and 1000 hours, the samples were taken out for oxidation induction time (OIT) and elongation at break tests, respectively. The test results are shown in Tables 2 and 3.

[0082] Comparative Example 1

[0083] Preparation of commonly used polyethylene pipe antioxidant test solutions.

[0084] The preparation method includes the following steps:

[0085] (1) Weigh out the amount of deionized water and sodium hypochlorite solid as described in Table 1. (2) Add the sodium hypochlorite solid to the deionized water, stir, and dissolve completely to obtain the polyethylene pipe antioxidant test solution of Comparative Example 1.

[0086] The temperature of the polyethylene pipe antioxidant test solution in Comparative Example 1 was raised to 40°C. Three identical dn63 polyethylene pipes (Shanghai Petrochemical YGH041T PE100) as in Example 1 were prepared as test samples. Two of the dn63 polyethylene pipes were immersed in the solution. After 500 hours and 1000 hours, the samples were taken out for oxidation induction time (OIT) and elongation at break tests, respectively. The test results are shown in Tables 2 and 3.

[0087] Comparative Example 2

[0088] Deionized water was used as Comparative Example 2. The amount of deionized water described in Table 1 was weighed, and the water was heated to 40°C. Three samples of the same DN63 polyethylene pipe (Shanghai Petrochemical YGH041T PE100) as in Example 1 were prepared as test samples. Two samples of DN63 polyethylene pipe were immersed in the solution. After 500 hours and 1000 hours, the samples were taken out for oxidation induction time (OIT) and elongation at break tests, respectively. The test results are shown in Tables 2 and 3.

[0089] Table 2 Oxidation induction time after immersion in test solution

[0090]

[0091] Table 3 Elongation at break after immersion in test solution

[0092]

[0093] The embodiments of this application are tested in accordance with the most common methods and standards in the pipe industry. All equipment and personnel used meet the requirements of laboratory accreditation standards (CNAS CL01) to ensure data reliability.

[0094] As can be seen from the data in Tables 2 and 3, the antioxidant test solution for polyethylene pipes prepared in the embodiments of the present invention can destroy the antioxidant system of polyethylene pipes. Moreover, the amount of tea polyphenols used is less than that of chlorine-containing disinfectants, which increases the difference in test results in the same amount of time, can more quickly distinguish the quality of polyethylene pipe special materials, and is more environmentally friendly than commonly used chlorine-containing disinfectants.

[0095] Example 4

[0096] Prepare a solution for testing the antioxidant properties of polyethylene pipes.

[0097] The preparation method includes the following steps:

[0098] Weigh out the deionized water, HCl solution (concentration 37%), NaOH solid, and tea polyphenol solid according to the amounts specified in Table 4; other preparation steps are the same as in Example 1 to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

[0099] Comparative Example 3

[0100] Prepare the antioxidant test solution for Comparative Example 3.

[0101] Weigh out the deionized water, HCl solution (concentration 37%), NaOH solid, and tea polyphenol solid according to the amounts specified in Table 4; other preparation methods are the same as in Example 4, to obtain the antioxidant test solution of Comparative Example 3.

[0102] Comparative Example 4

[0103] Prepare the antioxidant test solution for Comparative Example 4.

[0104] Weigh out the deionized water, HCl solution (concentration 37%), NaOH solid, and tea polyphenol solid according to the amounts specified in Table 4; other preparation methods are the same as in Example 4, to obtain the antioxidant test solution of Comparative Example 4.

[0105] Performance Test Examples

[0106] Three identical polyethylene pipes (Shanghai Yada Company, DN63 PE100) were prepared as Sample 1, and three identical polyethylene pipes (Shanghai Yada Company, DN63 PE80) were prepared as Sample 2. The temperature of the antioxidant test solutions prepared in Example 4, Comparative Example 3, and Comparative Example 4 was raised to 40℃, and two samples (Sample 1 and Sample 2) were placed in each of the three solutions. After soaking for 1000 hours, the samples were removed, and the oxidation induction time (OIT) was determined according to GB / T 19466.6-2009 standard (test temperature 200℃). The test results are shown in Table 5.

[0107] Table 4. Components (parts by mass) of the solutions in the examples and comparative examples

[0108] raw material Comparative Example 3 Comparative Example 4 Example 4 Deionized water 100 100 100 HCl solution 2 2 2 NaOH solid 1 1 1 Tea polyphenol solids 8 10 0.5

[0109] Table 5. Oxidation induction time (min) after immersion in the test solution

[0110]

[0111] As can be seen from Table 5, the amount of tea polyphenols in Comparative Examples 3 and 4 was too large, which led to excessive damage to the samples. After soaking for 1000 hours, the test performance of Sample 1 and Sample 2 was similar, with no obvious difference, and the test was meaningless.

Claims

1. A solution for testing the antioxidant properties of polyethylene pipes, comprising the following components in parts by weight: Water: 100 parts; Acid: 1-5 parts; Alkali: 0.2~4 parts; Tea polyphenols: 0.1~1 part; The solution has an acidic pH value.

2. The solution for testing the antioxidant properties of polyethylene pipes according to claim 1, characterized in that: Water: 100 parts; Acid: 1.5~3.5 parts; Alkali: 0.3~2 parts; Tea polyphenols: 0.3~1 part.

3. The solution for testing the antioxidant properties of polyethylene pipes according to claim 1 or 2, characterized in that: The acid is hydrochloric acid.

4. The solution for testing the antioxidant properties of polyethylene pipes according to claim 3, characterized in that: The hydrochloric acid has a mass fraction concentration of 37%.

5. The solution for testing the antioxidant properties of polyethylene pipes according to claim 1 or 2, characterized in that: The alkali is sodium hydroxide; The water is deionized water.

6. The method for preparing the solution for testing the antioxidant properties of polyethylene pipes according to any one of claims 1 to 5, characterized in that... Includes the following steps: The acid is added to water, then the alkali is added to make the solution acidic, then tea polyphenols are added, and the mixture is heated to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

7. The method for preparing the solution for testing the antioxidant properties of polyethylene pipes according to claim 6, characterized in that... Includes the following steps: (1) Add the acid to water, mix well, and then add the base to make the solution pH acidic; (2) Add tea polyphenols to the solution prepared in step (1) and stir; (3) Heat the solution obtained in step (2) to obtain the solution for testing the antioxidant properties of the polyethylene pipe.

8. The method for preparing the solution for testing the antioxidant properties of polyethylene pipes according to claim 7, characterized in that: In step (1), the pH value of the solution is between 3 and 6; In step (2), the stirring time is greater than 5 minutes.

9. The method for preparing the solution for testing the antioxidant properties of polyethylene pipes according to claim 7, characterized in that: In step (3), the heating temperature is 37℃~43℃.

10. The method for preparing the solution for testing the antioxidant properties of polyethylene pipes according to claim 9, characterized in that: In step (3), the heating temperature is 39~41℃.

11. A solution for testing the antioxidant properties of polyethylene pipes prepared by the preparation method according to any one of claims 6 to 10.

12. The application of the polyethylene pipe antioxidant test solution according to any one of claims 1 to 5 or the polyethylene pipe antioxidant test solution obtained by the preparation method according to any one of claims 6 to 10.

13. The application according to claim 12, characterized in that... This study aims to evaluate the antioxidant properties of polyethylene pipes used in drinking water.

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