Introduction to the compatibility test of packing material
When it comes to packaging testing, it's important to "improve efficiency" by eliminating the most time-consuming compatibility tests, especially those that don't. With the rapid development of material science today, the use of good materials can indeed help our end customers save a lot of testing work, but only compatibility testing cannot be omitted.
Definition of compatibility testing
The compatibility between cosmetic packaging and its contents broadly refers to the mutual influence between plastic packaging and cosmetics, including chemical compatibility, physical compatibility and biological compatibility.
The following is a brief description of the various types of incompatibilities:
Chemical incompatibility: Chemical components of the packaging materials, and chemical reactions between the decomposed products during processing and cosmetics components, have adverse effects on cosmetics or packaging materials; Chemical incompatibility is manifested as changes in the appearance and smell of packaging materials or cosmetics.
For example: the material becomes yellow, the package becomes yellow
Physical incompatibility: the packaging material and the contents have physical changes due to the mutual influence; The physical incompatible phenomena are penetration, adsorption, turtle crack, cracking, dissolution and so on. In the test judgment, physical incompatibility is often misjudged as chemical incompatibility. This is because physical incompatibility is more obvious and the reaction is more violent.
For example: crack, stress crack
Biological incompatibility: some substances in the packaging material migrate to cosmetics and have adverse effects on users; The performance is that the dissolved amount of harmful substances exceeds the measurement stipulated in the relevant cosmetic hygiene standards or norms in the country where cosmetics are sold; Under normal circumstances, harmful substances include a variety of plastic additives, residual solvents, volatile organic compounds, harmful metal elements, etc. Of course, not all dissolved plastic additives will have a serious impact on the properties of cosmetics, when the dissolved ingredients for one of the cosmetic ingredients, the amount of dissolved out is very small, the dissolved substances are harmless to users, this phenomenon of dissolved out of the normal compatibility.
For example, the colorant in the plastic is precipitated into the contents, which are originally off-white.
In view of the plastic cosmetics packaging material itself has a certain solvent resistance performance, cosmetics itself is relatively mild and other characteristics, cosmetics and packaging material incompatible phenomenon is more physical incompatible.
In addition, through the experiment of quantitative analysis of fine chemistry, it is proved that the incompatibility between cosmetics packaging material and its contents is usually not a single manifestation.
About the results of the compatibility tests
In fact, the expression form of the results of the compatibility test is quite complicated. Many colleagues often ask, since the compatibility is unqualified, all the samples should have reacted with the contents, and each sample should have some problems. Why are there good or bad samples at the same temperature? In fact, there is a certain ratio of unqualified compatibility, for example, at 40℃, 10 samples were tested, only 2 samples cracked, the remaining 8 samples remained intact, but when you expand the sample size to hundreds of samples, you will find that the number of cracking samples expanded to dozens of as many as; Similarly, if such packaging materials into mass production, the final problem is not a small number.
Examples of general practices for compatibility testing are: time, test conditions
Take the compatibility test scheme of a cosmetics giant as an example (the following test conditions can be selected according to different situations of products) :
A. General compatibility tests:
After weighing the empty packaging material, the contents are filled, and then assembled according to the process requirements and standards. At the same time, the assembled samples are weighed again and placed in different test environments as follows:
-20℃ 4℃ 23℃ 40℃ 50℃ Illumination (specific light source conditions) cyclic thermal shock 95% humidity, 30℃
Leave for 4-8 weeks, or longer
B. Stress cracking test:
Smear the contents at the assembly force position of the sample (e.g., screw thread, clamp position, etc.), and then assemble them according to the standard assembly force. Group the assembled samples into the following different test environments:
23 ℃ and 40 ℃ to 50 ℃
Leave for 4-8 weeks, or longer
C. After processing compatibility test:
Apply a layer of content to the finish processing (e.g. printing, electroplating, spraying, hot stamping, etc.) on the outer surface of the sample, and then group the samples into different test environments as follows:
23℃ 40℃ Circulating thermal shock 95% humidity, 30℃
The storage time is 10 days
At the end of the test period, the packaging material appearance, part of the mechanical property data, weight loss rate of the contents, stress fracture condition, aging condition, color migration condition, fragrance stability, content condition, etc., of the sample are evaluated and recorded.
The methods of testing vary from company to company, but most can be summed up as placing a sample under some of the harsher man-made environmental conditions for a long time, and then assessing the condition of the sample and the impact on the sample.
Some trends in compatibility testing
1. Shortened test time:
Due to the endless emergence of various new products, each company hopes to take the lead in the market share, so the domestic enterprises generally hope that the test can achieve "fast and accurate"; At present, even the compatibility test with the shortest time in the industry takes about four weeks. If the test fails in four weeks, packaging materials need to be re-selected, sampled and tested. Reopening the R&D cycle will inevitably result in greatly delayed product launch time. This requires the development of more reliable and convenient testing methods to improve efficiency.
2. Higher requirements for biocompatibility (safety) :
With the awareness of consumer safety, any slightest change in product safety can destroy a brand in an instant, so the safety aspect of compatibility testing has been raised to an unprecedented level. For terminal enterprises, detecting the precipitate of harmful substances requires a large amount of resources, and the degree of correlation with the main business is not high. Only a few very large multinational enterprises may set up specialized laboratories for special research. The current trend in the industry is for material suppliers or third parties to conduct relevant tests and issue relevant reports or certificates. It is worth mentioning that the industry now tends to apply food-grade materials in the development of cosmetic packaging materials.
3. Fusion simulated consumer use test:
In recent years, the use effect of cosmetics has become more and more closely related to the packaging. In order to verify whether the products can achieve the expected use effect, many companies have included in the compatibility testing method group a lot of matching tests for the use performance of packaging materials and contents. A body spray, for example, choose the packaging material is safe, no physical and chemical incompatibility is not incompatible, but the content contains a lot of powder materials, consumers in the process of discharging pump body, powder raw materials will be a partial blockage of the pump body lines, thus lead to the product pump out form not fog but straight line shape, consumers don't feel convenient to use and directly reduces the purchase desire again.
Similarly, some people also put forward the concept of production compatibility, such as whether the packaging material and the material body match in the production and filling process, whether the packaging material matches the actual filling process, and so on.
In order to make the packaging material better "compatible" with the use and production and transportation of consumers, it is necessary to have in-depth communication and cooperation with several departments in the early stage, so as to achieve the expected effect, maximize production efficiency, meet the needs of consumers to the greatest extent, and even bring surprises.