阅读说明：本技术 一种差示扫描量热仪自检用标准物质及其应用 (Standard substance for self-detection of differential scanning calorimeter and application thereof ) 是由 刘瑶 吴博 庞承焕 黄险波 叶南飚 宁红涛 刘思杨 于 2020-12-16 设计创作，主要内容包括：本发明提供一种差示扫描量热仪自检用标准物质。所述标准物质包括如下按重量份计算的组分：PE树脂99.4～99.8份；受阻酚类抗氧剂0.1～0.3份；亚磷酸酯类抗氧剂0.1～0.3份；所述PE树脂在200℃下,测量的OIT小于等于2min。本发型所述标准物质可以很好地代替标准金属作为差示扫描量热仪的标准物质,不仅成本低,而且检测准确更高,检测耗时短,稳定性高,可以作为一种快速测试手段,辅助监控固定温度下设备测试氧化诱导期的稳定性及数据准确性。(The invention provides a standard substance for self-detection of a differential scanning calorimeter. The standard substance comprises the following components in parts by weight: 99.4-99.8 parts of PE resin; 0.1-0.3 part of hindered phenol antioxidant; 0.1-0.3 part of phosphite antioxidant; the PE resin has a measured OIT of less than or equal to 2min at 200 ℃. The standard substance can well replace standard metal to serve as a standard substance of a differential scanning calorimeter, is low in cost, high in detection accuracy, short in detection time and high in stability, can serve as a rapid test means, and assists in monitoring the stability and data accuracy of the equipment under a fixed temperature in the oxidation induction period test.)

1. A standard substance for self-detection of a differential scanning calorimeter is characterized by comprising the following components in parts by weight:

99.4-99.8 parts of PE resin;

0.1-0.3 part of hindered phenol antioxidant;

0.1-0.3 part of phosphite antioxidant;

the OIT value of the PE resin is less than or equal to 2min at 200 ℃.

2. The standard substance of claim 1, wherein the PE resin is recycled.

3. The standard substance according to claim 1, wherein the standard substance is prepared by adopting an internal mixing method, the internal mixing condition is that the internal mixing time is 8-10 min, and the internal mixing temperature is 180 +/-5 ℃.

4. The standard substance as claimed in claim 1 or 3, wherein the mixing conditions are a mixing time of 10min and a mixing temperature of 180 ℃.

5. The standard substance according to claim 1, wherein the hindered phenolic antioxidant is antioxidant 1010.

6. The standard substance of claim 1, wherein the phosphite antioxidant is antioxidant 168.

7. The standard substance according to claim 1, wherein the hindered phenol antioxidant is mixed with the phosphite antioxidant in equal proportion.

8. A method of self-testing a differential scanning calorimeter using a standard substance according to any one of claims 1 to 7, wherein the standard substance is used in place of a standard metal substance and the standard substance is formulated as follows for the OIT value at 200 ℃ of the apparatus:

99.8 parts of PE resin;

0.1 part of hindered phenol antioxidant;

0.1 part of phosphite ester antioxidant.

9. A method of self-testing a differential scanning calorimeter using a standard substance according to any one of claims 1 to 7, wherein the standard substance is used in place of a standard metal substance and the standard substance is formulated as follows for the OIT value at 210 ℃ of the apparatus:

99.6 parts of PE resin;

0.2 part of hindered phenol antioxidant;

0.2 part of phosphite ester antioxidant.

10. A method of self-testing a differential scanning calorimeter using a standard substance according to any one of claims 1 to 7, wherein the standard substance is used in place of a standard metal substance and the standard substance is formulated as follows for the OIT value at 220 ℃ of the apparatus:

99.6 parts of PE resin;

0.3 part of hindered phenol antioxidant;

0.3 part of phosphite ester antioxidant.

Technical Field

The invention relates to the field of instrument correction, in particular to a standard substance for self-detection of equipment for measuring an oxidation induction period by a differential thermal analysis method and application thereof.

Background

The oxidation induction period is one of important performance indexes of the existing cable material, the existing equipment for testing the oxidation induction period is mainly a differential scanning calorimeter, the existing domestic common test brand still has some defects in equipment stability, and the accuracy of test data of equipment oxidation induction period items needs to be monitored regularly. Since there is no relevant standard substance for daily self-test of the equipment on the market at present, the common means for self-test of the equipment is to use standard metals of indium (In, melting point 156.61 ℃) and tin (Sn, melting point 231.89 ℃) to test the temperature stability and accuracy.

However, the temperature test conditions commonly used in the oxidation induction period test are 200 ℃, 210 ℃ and 220 ℃, the temperature is a main influence factor of the oxidation induction period, and experiments show that the oxidation induction period test values of the same material under different temperature sections are greatly different. Taking MDPE-5105 as an example, the oxidation induction period is 68.4min at 200 ℃, 41.0min at 210 ℃ and 19.5min at 220 ℃. It can be seen that the effect of the change in temperature on the oxidative induction period is very significant. In addition, instrument self-inspection using standard metals indium and tin cannot be accurate to the required test temperature, and the influence of temperature range fluctuation may exist. Meanwhile, atmosphere, gas flow rate, sample size, sample shape, temperature rise rate and the like all have certain influence on the sample, so that the instrument self-inspection is carried out by using standard metal, and the problem that the accuracy self-inspection characterization of the oxidation induction period project test cannot be comprehensively carried out exists.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a standard substance for self-checking of a differential scanning calorimeter, which can more accurately perform self-checking on the differential scanning calorimeter compared with a standard metal.

The invention also aims to provide a method for using the standard substance for the self-detection of the differential scanning calorimeter in the self-detection of the differential scanning calorimeter.

The above purpose of the invention is realized by the following technical scheme:

a standard substance for self-detection of a differential scanning calorimeter comprises the following components in parts by weight:

99.4-99.8 parts of PE resin;

0.1-0.3 part of hindered phenol antioxidant;

0.1-0.3 part of phosphite antioxidant;

the OIT value of the PE resin is less than or equal to 2min at 200 ℃.

Compared with the standard metal with only one melting point, a plurality of standard substances suitable for different detection temperatures can be obtained by slightly adjusting the formula of the PE resin standard substance, the oxidation induction period of the self-detection standard substance can be controlled within a reasonable range, and the problems of inaccuracy and overlong detection time of the conventional standard substance are solved. If the OIT value of the PE resin is too high, the condition that the quality of a sample is floated and unstable easily occurs, the PE resin with the OIT value less than or equal to 2min is selected, the banburying process can be better controlled, and a standard substance with the oxidation induction period of 10-20 min can be obtained more easily.

More preferably, the OIT of the PE resin is measured at 200 ℃ for 1-2 min.

Preferably, the PE resin is recycled. The PE resin of the reclaimed material has lower cost and is more easily obtained.

Preferably, the standard substance is prepared by adopting an internal mixing method. The banburying condition can affect the dispersion condition of the antioxidant in the system, and meanwhile, because the addition amount of the antioxidant is small, if the banburying time is insufficient, the OIT value fluctuation of sample quality inspection is easy to cause. More preferably, the banburying conditions are that the banburying time is 8-10 min and the banburying temperature is 180 +/-5 ℃.

Most preferably, the mixing condition is most preferably mixing time 10min and mixing temperature 180 ℃. Under the condition, different formulas are adjusted to obtain the standard substance with proper oxidation induction period suitable for the temperature of more than 200 ℃.

The hindered phenolic antioxidant is a commonly used antioxidant, most preferably, the hindered phenolic antioxidant is most preferably antioxidant 1010.

Phosphite antioxidants are one of the commonly used antioxidants, most preferably, the phosphite antioxidant is most preferably antioxidant 168.

More preferably, the hindered phenol antioxidant and the phosphite antioxidant are preferably mixed in equal proportion.

More preferably, the preparation method of the standard substance comprises the following steps: mixing and shaking the components uniformly, then pouring the mixed sample into an internal mixing module, keeping the temperature of the internal mixing module constant at 180 ℃, and carrying out internal mixing for 10min to obtain the standard substance.

As mentioned above, the OIT value is closely related to temperature, and in order for the standard substance to meet the self-test requirements for OIT, it is preferred that the OIT value of the standard substance fluctuate by less than 10%, and that there be shorter OIT values at different test temperatures. More preferably, aiming at the common self-test of 200 ℃, 210 ℃ and 220 ℃, the invention adopts the following corresponding preferred scheme:

a method of self-testing a differential scanning calorimeter using the standard substance, replacing a standard metal substance with the standard substance, and using a standard substance formulation for OIT values at 200 ℃ of the apparatus:

99.8 parts of PE resin;

0.1 part of hindered phenol antioxidant;

0.1 part of phosphite ester antioxidant.

Under the method, the standard value of the standard substance tested under the temperature condition of 200 ℃ is (18.3 +/-1.8) min.

A method for self-testing a differential scanning calorimeter using the standard substance, the standard substance replacing a standard metallic substance, and using a standard substance formulation for OIT values at 210 ℃ of the equipment:

99.6 parts of PE resin;

0.2 part of hindered phenol antioxidant;

0.2 part of phosphite ester antioxidant.

Under the method, the standard value of the standard substance tested under the temperature condition of 200 ℃ is (20.4 +/-2) min.

A method for self-testing a differential scanning calorimeter using the standard substance, wherein the standard substance is used in place of a standard metal substance, and the standard substance formula is as follows for OIT value at 220 ℃ of equipment:

99.6 parts of PE resin;

0.3 part of hindered phenol antioxidant;

0.3 part of phosphite ester antioxidant.

Under the method, the standard value of the standard substance tested under the temperature condition of 200 ℃ is (16.0 +/-1.6) min.

The standard substance of the invention can still meet the requirement of tolerance after long-term storage (more than half a year).

Compared with the prior art, the invention has the following beneficial technical effects:

the invention provides a standard substance for differential scanning calorimeter self-inspection, which takes PE resin as a base material, is matched with an antioxidant and a proper processing method, can well replace standard metal as the standard substance of the differential scanning calorimeter, has low cost, higher detection accuracy, short detection time and high stability, and can be used as a rapid test means to assist in monitoring the stability of equipment under a fixed temperature and testing the oxidation induction period and the data accuracy.

Detailed Description

The present invention will be described in further detail with reference to specific examples and comparative examples, but the present invention is not limited to the examples.

In the examples, the starting materials not specifically mentioned are all conventional commercial products.

PE resin reclaimed material A: trade mark, source (trade mark: PE-LT17BK01ML source: Japanese miscellaneous feeds)

PE resin reclaimed material B: brand and source (source of YBL-PE01ZK is produced by self-mixing)

Antioxidant 1010 and antioxidant 168 are commercially available.

The oxidation induction period of the PE resin reclaimed material A is 1.3 +/-0.2 min at the temperature of 200 ℃. The oxidation induction period of the PE resin reclaimed material B is 3.4-7.2 min. The oxidation induction period of the recovered PE resin B itself is unstable, and therefore, it is not suitable for preparing a standard substance.

And (3) exploring a proper formula and banburying conditions to prepare the standard substance by using the PE resin reclaimed material A. Specifically, the process according to table 1 comprises the following steps: mixing and shaking up the components with the total amount of 50g, then pouring the mixed sample into an internal mixing module, setting the temperature of the internal mixing module at a constant value, and adjusting the internal mixing time to obtain different standard substances. And OIT of the standard substance at 200 ℃ was measured as shown in Table 1.

TABLE 1

From the conditions shown in Table 1, the mixing conditions have a strong influence on the OIT of the standard material, and when the mixing temperature is too low, the OIT time is longer, and when the mixing time is too short, the dispersion of the antioxidant is affected. In addition, the banburying temperature is increased, the OIT value is obviously reduced, and the antioxidant is more prone to lose efficacy at higher temperature.

In addition, in order to improve the correction accuracy, the standard substance with the OIT time of 10-20 min is more suitable. At 190 ℃ the OIT value of the standard material is already close to 10min, which is not supposed to be suitable for the correction above 200 ℃.

Therefore, most preferably, the banburying conditions are that the banburying temperature is 180 ℃ and the banburying time is 10 min.

According to the above-mentioned mixing conditions, 3 sets of sample formulations are provided, as shown in table 2:

TABLE 2

The samples of each example were specifically prepared as follows:

(1) weighing: the mass of each component of each formula is accurately calculated by taking 50g as the total amount, and the components are weighed according to the required mass.

(2) Uniformly mixing: pouring all weighed samples into a transparent self-sealing bag, sealing, and then shaking up by hand for at least 10min to ensure that the samples and the antioxidant are distributed uniformly;

(3) standby: after 3 samples with different formulas are mixed uniformly in sequence, marking for later use;

(4) heating to 180 ℃ by using an internal mixing module, and stabilizing the temperature of each module for at least 10 min;

(5) and pouring the standby mixed sample into an internal mixing module, carrying out internal mixing for 10min to ensure that the sample is uniformly mixed, and then taking out the sample. I.e. the standard substance.

Testing of each standard substance: taking samples prepared in the same batch in the above examples 1 to 3, respectively taking 5 groups of balance samples, raising the temperature to a specified test temperature (200 ℃/210 ℃/220 ℃ in sequence in examples 1 to 3) at a heating rate of 20 ℃/min in a nitrogen (99.99 percent and 50mL/min) atmosphere, switching to an oxygen (99.5 percent and above and 50mL/min) atmosphere, and keeping the temperature for 30 min; the oxidative induction period OIT of the standard substance of each example was measured and is shown in Table 3.

TABLE 3

Standard substance rating: combining OIT characteristics, the sample fluctuation is required to be less than 10%, and the PE-OIT-200 of example 1 is tested under the temperature condition of 200 ℃ for standard value of (18.3 +/-1.8) min; the PE-OIT-210 of example 2 has a standard value (20.4 +/-2) min under the temperature condition of 210 ℃; the PE-OIT-220 of example 3 was tested at 220 ℃ for the standard value of (16.0. + -. 1.6) min. All meet the requirements

Data tracking: the sample is sealed and stored in dark, and the verification test is carried out after half a year, and the test data is still stable within the range.

Table 4 is the validation test data after half a year storage:

TABLE 4 verification test half a year later

It can be seen that the standard sample prepared by the invention is still very stable after long-term storage, and meets the use requirement.