What causes plastic to deteriorate?
- What is plastic "creep"?
- The overlap of several external factors
- Material itself changes over time.
A single external factor
When handling plastic products, the concepts of "deterioration" and "life span" cannot be ignored.
This section explains the causes of plastic degradation and reaching the end of its life.
- continuous service
- organic solvent
- Stress and strain
The resistance to these external factors depends on the type of plastic.
Therefore, it is important to use plastic as a material that has the necessary resistance to the environment in which it will be used.
For example, plastics used as materials for parts that are used in an environment that is easily exposed to heat need to have high heat resistance, or "heat resistance".
There are different types of plastics, each with different statuses such as heat resistance, impact resistance and weather resistance.
Understand the characteristics of each material and consider other factors (such as price and formability) when selecting the most suitable material.
The overlap of several external factors
In some cases, the external factors that cause plastic to deteriorate are not a single one, but multiple factors at the same time.
Components and products used outdoors, for example, are subject to outdoor exposure to sunlight (ultraviolet light), air and rain.
We also need to consider "stress cracking", which is the simultaneous effect of some environmental substance (such as a drug) along with stress and strain.
Again, it is important to assume in advance how the environment in which you will be used will affect the plastic, and to select a plastic material with the necessary resistance.
Material itself changes over time.
Even in the absence of the external factors described above, it is also necessary to consider that the plastic material itself can deteriorate over time.
- Polymerization of thermoplastic resins (continuation of the reaction)
- Progress of the curing reaction of rubber and thermosetting resin
- Volatilization of plasticizers in rubber and PVC
To put it plainly, plastics are not in a chemically stable state, but in a state that is in the process of undergoing chemical change.
Since it will be used in that state, even if it is unaffected, the reaction will progress and deteriorate over time.