ISO 23075:2021 pdf free download – Vulcanized rubbers – – Determination of antidegradants by high- performance liquid chromatography.
D.1 General
An interlaboratory test program (ITP) for precision evaluation for antidegradant content with external calibration was carried out in 2019, using precision procedures and guidelines as described in ISO 19983:20 17 Method A.
The ITP was conducted using compounds, for both uncured and cured mixes, based on NR stabilized by 6PPD (N-1,3-dimethylbutyl-N’-phenyl-p-phenylenediamine) and ODPA (octylated diphenylamine). The NR compound was vulcanized at low temperature (100 °C, using a ZBZC/CBS/TbzTD system) to minimize loss of antidegradant.
The testing was conducted on a day 1 vs day 2 repeatability basis, with 7 days between the day measurements. On each day, the test is duplicated and the test result is the mean value of two individual determinations of antidegradant content.
D.2 Precision results
Seven laboratories participated in the ITP. A test result represents the mean for two individual determinations of antidegradant content obtained on each of material on two different test days, seven days apart.
General statements for the use of the precision results are given in terms of both the absolute precision, rD and R, and the relative precision, (rD) and (R). The precision data resulting from the ITP, using the outlier replacement and outlier deletion procedures, are set forth in Table D.1 for 6PPD, in uncured and cured NR, and in Table D.2 for ODPA, in uncured and cured NR.
The precision results as determined by this ITP may not be applied to acceptance or rejection testing for any group of materials or products without documentation that the results of this precision evaluation actually apply to the products or materials tested.
The ITP repeatability and reproducibility statements are as follows:
Repeatability – The within-day repeatability has been established for each material by the values found in Table D.1 or D.2. Two single test results (obtained by the proper use of this document) that differ by more than the tabulated values for r, in measurement units and (r), in percent, shall be considered as suspect, i.e. to have come from different populations. Such a decision suggests that some appropriate investigative action be taken.
Day-to-day repeatability – The day-to-day repeatability, or local domain precision, has been established for each material by the values found in Table D.1 or D.2. Two single test results (obtained by the proper use of this document) that differ by more than the tabulated values for rD, in measurement units and (rD), in percent, shall be considered as suspect, i.e. to have come from different populations. Such a decision suggests that some appropriate investigative action be taken.
Reproducibility – The reproducibility, or global domain precision, has been established for each material by the values found in Table D.1 or D.2. Two single test results obtained in different laboratories (by the proper use of this document) that differ by more than the tabulated values for R, in measurement units and (R), in percent, shall be considered as suspect, i.e. to have come from different populations. Such a decision suggests that some appropriate investigative action be taken.