What is the reason for TPE product precipitation
Source：德創化工Time：2019-11-14Hits：2820
For some TPE products, precipitation often occurs. What are the common precipitation forms? What are the reasons? Next, the editor will explain to you about the precipitation of TPE products, hoping to help you.
First of all, say what is precipitation, precipitation, refers to the solute separated from the solution (in a crystalline state), or solid matter separated from the gas.
Precipitation experiment, the most typical is the evaporation experiment of middle school chemistry (as shown in the figure below). The bottom of the round-bottomed flask containing salt water is heated with alcohol lamp flame. As the water volatilizes gradually and decreases, salt will precipitate and precipitate at the bottom of the flask. As for the cause of precipitation, salt has a certain solubility in water. A certain amount of water can only dissolve quantitative experiments. When the water gradually decreases, salt will gradually precipitate.
What about TPE product precipitation?
TPE is a polymer material, and other components will be added to its blending system. To make a metaphor that may not be very appropriate, the substrate of TPE (such as SEBS+ resin) can be regarded as a solution, and other trace components can be regarded as solute. Then different components have different solubility in TPE (solubility refers to the maximum amount that the component stably disperses in a certain TPE, and if the added amount exceeds the amount, there will be precipitation risk).
The precipitation of solids from liquids is usually faster and easier to show. However, as a polymer mixing system, the precipitation of components with excessive addition amount is a process of gradual migration and seepage from the inside of the mixing system (usually a product with a certain volume) to the surface. Therefore, we often find that after TPE products are processed, the surface precipitation phenomenon will not be found immediately, but will only occur after a certain period of time, which is uncertain and is usually possible within a few days to a month or two after the products are processed.
Common Forms of Precipitation of TPE Products
1. Oil production
This is due to the precipitation of operating oil in TPE system.
Factors leading to precipitation: selection of rubber substrate, selection of operating oil, material basis injection molding process, etc.
2. Whitening
This is due to the precipitation of white small molecule solid additives in TPE system.
Reason for precipitation: the added amount exceeds the standard.
3. Spitting acid
This is due to the precipitation of small molecule co-additives in TPE system.
Reason for precipitation: the added amount exceeds the standard.
4. Color string
The separation and precipitation of toner masterbatch from TPE system.
Reason: The color agent is incompatible with the main system.
Common cases of precipitation:
Oil on the surface of earphone cable data line, oil on the surface of TPE products (e.g. hoses) with higher hardness, white on the surface of tool handle, sticky coating of electronic products, etc.
