Overseas shipments of dangerous goods (on)

In the transport of dangerous goods, the use of plastic packaging and bulk containers is becoming increasingly widespread. Typical packaging is drums and drums (capacity 220 liters) and rigid bulk containers (volumes 500-1500 liters). Small-capacity packaging containers such as fiberboard boxes are commonly used for secondary transport packaging.
If packaging containers and bulk containers are used in hazardous transport, UN certification must be obtained. For European road and rail transport, ADR/RID regulations should be followed. This means that in addition to the mechanical tests, the chemical or physical compatibility of the package with the contents must also be carried out according to a specific test procedure. During this test, accelerated testing with standard fluids can reduce test work to a minimum compared to the UN recommended test procedure.
In the design and application of packaging containers and bulk containers, several important developments are: the application of new materials and new packaging concepts, and the application of recycled and recycled materials. The UN recommendations and regulations on the transport of dangerous goods have partially acknowledged the developments in these areas and have made corresponding provisions for them. However, in order to be able to fully consider the development of these areas and benefit from it, it is necessary to pay more attention and study.
1. New materials and new packaging concept According to the traditional theory, high-molecular high-density polyethylene is used for blow-molded packaging and bulk containers, while cross-linked polyethylene is used for rotating plastic bulk containers. The following items are noteworthy:
(1) Linear Low Density Polyethylene (LLDPE) is being used for bulk containers that have been UN certified;
(2) Introducing multilayer concepts and different materials between layers;
(3) For small-capacity packaging, other types of polyethylene and other materials such as polyethylene terephthalate are used.
These developments will have a significant impact on UN-certified test procedures, particularly chemical/physical compatibility tests. According to the standard procedure, if you want to obtain the certification, you should first store it together with the chemicals to be transported for six months before carrying out the mechanical testing of the packaging or bulk containers. Of course, this is a lengthy and delicate process. Therefore, Europe has studied a temperature program that can shorten the storage cycle to 3 weeks, accelerate the degradation process by increasing the test temperature to 40°C and introducing standard fluids. This standard fluid represents some kind of interaction (expansion, environmental fracturing, chemical degradation). By crossing, most chemicals can be simulated without further testing of packaging containers or bulk containers. This mechanism has been used for a long time and is now used for high molecular density polyethylene.
Although there have been some developments in packaging materials and concepts, it is still necessary to further study standard fluid systems. Therefore, a research project called CHEMPACK was launched in December 1997. The plan was funded by the European Commission and shared by six raw material producers, four packaging/bulk container manufacturers, and four experimental institutions. . This plan is coordinated by TNO with a total budget of 1.1 million euros. The goal of the plan is to study conformance testing methods and processes for evaluating the chemical and physical compatibility of plastic packages or bulk containers. This means developing a standard fluid system not only by evaluating and improving the current polymer high density polyethylene approach, but also by developing similar systems for other types of polyethylene, just as the current packaging philosophy and bulk container use. When using these standard fluids without further testing, many chemicals can be simulated. Especially for mixtures, the laboratory method must be used to compare the effects with standard fluids. If the test result of the item is smaller than the result of the standard fluid, the item can be approximated as a standard fluid. In the CHEMPACK program, critical assessments of these methods are being carried out in accordance with the goal of formulating a set of clear and consistent methods.
The results show that so far it has been possible to use standard fluid systems for polyethylene type materials. The new fracturing method for environmental fracturing that the plan will consider is a constant-pressure full-groove stretch test.
2. Packaging Recycling Rigid plastic packaging and the reuse of bulk containers have been used in closed processes for many years, ie same or similar chemical products transported by suppliers to customers for reuse of packaging and bulk containers. (To be continued)