TPV thermoplastic vulcanizate is composed of polypropylene, EPDM, emollient oil, fillers and additives. According to different hardness, adjust proportion of plastic and rubber, and proportion of oil expansion. The addition of an emollient oil can reduce hardness of TPV and improve handling characteristics of TPV, but too much emollient oil usually precipitates easily and causes stickiness. It is difficult to determine exact amount of softener oil added at start of a formulation because settling of softener oil requires a process and depends on ambient temperature. If temperature is too high or too low, settling of the oil can be accelerated.
In general, for TFE with a relatively high degree of vulcanization, oil deposition can be associated with a high ambient temperature. relation.
In picture above, 8201-90. According to customer reviews, it was sticky. Put product on kraft paper and give it strength. As a result, a mimeograph appeared on kraft paper.
In order to determine how much emollient oil is appropriate to add to TPV, we have developed an evaluation method, specific method is as follows: a standard injection molded test piece is processed in an oven at a certain temperature and for a certain time, and then a test personnel who have passed preliminary uniform assessment method conduct a subjective assessment. Rating scale: ①Very dry and does not feel sticky even when touched very hard, score 4; Slightly sticky, score 2 points, ④ dry feeling, light touch, obviously sticky, score 1 point, ⑤ feels very dry, does not need to be touched, oil deposits are visible to naked eye, a little shiny when viewed with a refraction of 0 points. Finally, average scores of 3 testers (the more better).
The figure below shows evaluation of stickiness of material under high temperature conditions:
The above assessment results are largely consistent with our projected results. Roughly speaking, a high-flowing grade N1090AN-I, since, given flowability, amount of emollient oil added is slightly higher, which leads to a certain slight stickiness at high temperatures.
Of course, aging time at high temperatures can be increased to make contrast more apparent.
A similar estimation method can also be used for low-temperature precipitation.