[Abstract] The full text introduces the importance, classification, basis and method of packaging aging test, the focus of actual operation and the evaluation of results.
Packaging aging test
- The importance of aging tests
The aging test is also an important item to be considered in MDSP design. Because it is a product with high safety requirements for medical devices, the aging test is related to the guarantee of the expiration date of the product, so it cannot be ignored. The conclusive report of the test can also be submitted to the relevant agency for review, such as the CE certification of the European Union or the FDA’s 510K application, and is a supporting document for the validity period of the product.
In several versions of the ANSI/AAMI/ISO 11607 standard, there has always been a very clear statement: “The manufacturer should be responsible for proving that the final packaging of the product is subjected to long-term circulation and storage, as long as the packaging is not Damaged or unopened, and the paper is fed under the storage conditions specified by the manufacturer, and the packaging should be kept intact during the validity period of the product labeling. This paragraph is the most direct authoritative standard basis for the product aging test. However, this standard is a general standard after all. It only mentions that the aging test should be carried out to ensure the validity of the product, but it does not mention the details of how to carry out the aging test.
In fact, it is not difficult to find out that this test is actually a systematic, complicated and long-term sample environment adjustment process from a very scientific point of view. It is in fact a systematic, complex and long-term sample environment adjustment process, which is in accordance with the test sample adjustment process specified in ASTM D4332. It is essentially the same, that is, the sample is adjusted in a specific environment for a certain period of time, and then the necessary physical, chemical, biological and mechanical properties of the samples subjected to the specific environment adjustment are tested to prove the sample. Whether there are various performance differences before and after environmental adjustment. If a simple sentence is used to summarize the aging test, over-packaging should be: the aging test is a long-term, systematic process that does not involve product performance testing.l?’
- Classification of aging tests
The aging test can be divided into Real Time Aging Testing and Accelerated Aging Testing according to different properties. As the name implies, the former is placed under normal temperature environment, or in the expected circulation environment of the product, until the expiration of the design expiration date, and then the packaged product is taken out for related performance test, and this performance is The results of the test are compared with the results of the sample performance test before the aging test to determine whether the validity period of the product is reasonable. The accelerated aging test is to design a specific aging test environment, which greatly shortens the duration of the usually very long aging test. There is a correlation between this specific environment and the ratio of shortened time.
It can be seen that the wine packaging, the real aging test is very simple, but the time required is very long, may not be suitable for the fierce market competition on the timeliness requirements, so often use accelerated aging test. However, the true aging test is indispensable because its result is the most accurate and authoritative aristocratic crown, and the result of the accelerated aging test is only a transition. When the results of the real aging test come out, the final aging is still required. test results. The focus of this paper is on the relatively complex accelerated aging test.
- Basis and method of accelerated aging test Before discussing the MDSP accelerated aging test, the author must first declare that: This is a fuzzy scientific digital printing post-press processing, because the chemical reaction involved in the test itself is too complicated, and its theoretical basis It has not been confirmed by scientific authority so far.
The relevant standard for the MDSP accelerated aging test is ASTM F1980, which is not a very long launch time. It is a working group F02.60 of ASTM (F02 is the working group on flexible packaging standards in ASTM, and 60 is in the F02 working group). About the MDSP subordinate working group) A standard specifically developed for the MDSP accelerated aging test. Currently there are two versions of the standard activities, the original May 1999 version and the updated January 2002 version after 3 years. . ASTM F1980 is also the first officially published guide to how to conduct MDSP accelerated aging tests, which should be a significant improvement in the evolution of packaging accelerated aging tests. Of course, this is not to say that there are no guidelines or programs for accelerating aging tests before the introduction of this standard, but some methods are not systematic or universal.
The main content of ASTM F1980 includes guidance on how to prepare packaging accelerated aging test schemes, as well as some related information representations and statements, but does not involve real aging test protocols and some specific test methods for judging product packaging performance.
The theoretical basis for the accelerated aging test is explicitly mentioned in ASTM F1980 and is described in Section 6.3 of Part VI: The accelerated aging test theory is based on the assumption that the chemical reaction of material deterioration follows the Arrhenius reaction rate law. This law stipulates that when the temperature increases or decreases by 10 °C in a single process, the chemical reaction acceleration factor Q10 corresponds to an increase or decrease of approximately one time. Of course, there is some information content behind this theory that needs to know about folding. For example, packaging materials are always affected by external environmental factors. For example, to accurately determine the acceleration scale factor Q10 in Arrhenius theory is a very complicated process that requires the power of material reaction. Learning models, so the conservative Q10 values are generally used in MDSP, such as 2.0.
Here, the author will not describe the manufacturer information of this complex Arrhenius theory in detail, and only give a case of a simple calculation method for the reader to learn by himself.
As stated by Arrhenius theory, “a temperature change of 10 °C will cause the chemical reaction rate to double”, so the Accelerated Aging Rate (AAR) is calculated as:
AAR=Q10 ( Te – Ta ) /10
Among them, Te is the experimentally controlled ambient temperature (Elevated Temperature) and Ta is the normal ambient temperature (Ambient Temperature).
Thus, the Accelerated Aging Time Duration (AATD) should be:
AATD=Desired Real Time/AAR
Here, AATD is the duration of the accelerated aging test corresponding to the expiration date. For example, packaging logistics, if the product design is valid for 3 years, the normal ambient temperature is 22 °C, and the predetermined accelerated aging test ambient temperature is 55 °C, and the accelerated aging factor Q10 is 2.0, the AAR is calculated as follows:
AAR=2.0 (55-22)/10 =9.85
Then the test time for the aging test every 1 year is
AATD=365 days/9.85=37.06 days
That is, the AATD is 38 days/year (Note: when calculating, the decimal point plus 1 is rounded)
Therefore, variable data printing, simulation 3 years of aging test test time is 38 × 3 = 114 days.
In the actual accelerated aging test, the following matters concerning the accelerated aging theory should be noted:
(1) When the aging test environment temperature exceeds 50 °C, the relationship between reaction rate and temperature may not be linear, which is why the aging temperature cannot be too high. Of course, if the aging temperature is set too low, it is almost the same as the real aging test. Therefore, in general, ticket printing, in order to balance the relationship between the aging test duration and the stability of the chemical reaction, the accelerated aging test temperature is usually set at 55. °C, this is the conclusion that the author has obtained from many foreign related literatures. It is recommended not to exceed 60 °C in ASTM F1980.
(2) As mentioned above, the accelerated aging test is a fuzzy science publishing dynamic, and the reaction rate of packaging materials containing various chemical components in the accelerated aging process may also be diversified, but the actual operation is to make a one-size-fits-all process. Just assume that Q10 is 2.0.
(3) Excessive test temperature can cause packaging materials to be exposed to problems that are impossible at room temperature, resulting in unconventional and unpredictable failures in the aging test, which is why the accelerated aging test temperature cannot exceed 60 °C. One.
(4) There is no published authoritative scientific literature to prove that the aging test theory is effective for packaging materials. Of course, digital printing machines, since ASTM can publish relevant standards, fully demonstrate that although the MDSP accelerated aging test theory cannot be fully scientifically proven, in actual industrial production operations, the results of the MDSP accelerated aging test are reliable, or at least It is of reference value.
The method of accelerating aging test is not the only one-dimensional printing. In the process of reviewing the data, the author also found that some existing test environments for specific products are also different, such as temperature 40 ° C, humidity 60% environment for two weeks There are metal packages with a temperature of 70 °C, humidity of 15% and 85% in an alternating environment for two weeks, with a temperature of 60 °C and a humidity of 80% for one week. However, these methods cannot find a theoretical basis, and may be more It is summed up by the accumulation of experience, and the product and its expected circulation process are highly targeted, and the reference value of the MDSP accelerated aging test research is not great. 4. Accelerate the focus of the actual operation of the aging test. The MDSP accelerated aging test is also very practical in practice, which means that not carefully reading an ASTM F1980 can understand how to properly perform the accelerated aging test. The following items are worth practicing. Focus on the operation:
(1) Before the accelerated aging test is conducted, there must be a written test plan signed by the responsible person to specify how the test should be conducted.
(2) The test instruments and equipment used in the test shall be calibrated and recorded.
(3) It is useful to understand the changing trend of aging effects when characterizing the aging effects of materials and packaging properties, as this allows the test designer to detect the test time points in question and take measures to remedy the organization/organization. Instead of wasting a lot of manpower and material costs, it only gets a conclusive report of trial failure.
(4) The initial, sterilized and accelerated aging packaging samples may be free of products or replaced with simulated products. Of course, it is better to use the final complete product, so that although the cost is higher, the test results can best simulate the actual situation. Therefore, it is also the most authoritative and credible; of course, ink, in some cases, may have to be tested with the final complete product.
(5) The process-tested samples should be selected for the aging test because such samples are the most reliable and are continuously stable. And if the aging test is performed on a sample that does not ensure consistent quality, the time cost of the test may not be affordable for every business.
(6) Sample sterilization should use a validated sterilization procedure, as the sterilization process may affect the stability of the packaging material or system for inkjet printing, so the worst sterilization conditions should be used, including the worst sterilization parameters. And the number of sterilizations increased in two cases.
(7) Although the Arrhenius theory does not mention the role of humidity in the acceleration of chemical reactions, it should be considered in combination with the characteristics of packaging materials and products. The effect of humidity should be considered in the accelerated aging test, that is, the humidity should be controlled in the conventional range. Inside.
(8) Samples that have completed the accelerated aging test cannot be immediately subjected to various performance test prepress processes. Sample adjustment should be carried out in accordance with ASTM D4332, generally in a conventional environment, ie, temperature (23 ± 2) ° C, humidity 50% ± 5 Adjusted for 24 hours in % environment; in combination with actual conditions, some samples also need to be transported. The transport test plan should refer to the appropriate one of the ISTA (International Safety Transit Association), and used in the series of test protocols. The sample for the transport test must be a complete sample. (9) The packaging performance of the samples after accelerated aging test should be evaluated against the performance requirements of the original packaging, and the conclusion is drawn as to whether the samples are qualified after the accelerated aging test.
- Accelerated aging test results The final remaining question may be how to evaluate the results of the accelerated aging test. There are two cases in this evaluation:
(1) If the accelerated aging test results meet the acceptance criteria, the expiration date of the product depends on the CTP of the results of the actual aging test, which is also in line with the expected routine.
(2) If the accelerated aging test results do not meet the acceptance criteria, then there are two options: the first is to investigate the production process of the product packaging process, redesign the product or packaging, try to verify the shorter product validity period; the second is to wait for the real aging The test results, if the true aging test results are through the color sequence, then in this case, we can only prove that the accelerated aging test we designed is more strict and conservative than the actual situation.
The results of the real aging test also have the same model assessment problem: if the true aging test results meet the acceptance criteria, then the validity period of the package is verified; if the true aging test results do not meet the acceptance criteria, the shelf life must be reduced to the one that has passed the true aging test. For the longest time, this is the importance of setting a few aging test test points to grasp the trend of aging test. If the product has been placed on the market based on risky accelerated aging test data (ie, the accelerated aging test passes the prepress process and the true aging test fails), careful review and documentation must be collected and appropriate Remedial measures to circumvent relevant market risks.