High resilience sponge in our lives everywhere, and silicone oil is an indispensable component of the sponge, it is used to adjust the structure of the bubble pore, to play the role of emulsification, nucleation, reduce surface tension, the dosage is small but vital, how to professionally evaluate it, technical workers have their own methods, how to select a good product, I’ll share some of our experience in evaluating silicone oil.
First, the stability of silicone oil test
1.1 Storage stability test of silicone oil
Storage stability of silicone oil at low temperature
The silicone oil is injected into a 1L glass bottle and placed in the refrigerator for 24 hours to observe whether there is any delamination of the silicone oil. If it is not obvious, take out the silicone oil and the silicone oil at room temperature to do a comparison experiment to see whether the closed pore and vesicle structure of the silicone oil is normal, and if there is any abnormality, it means that the silicone oil cannot be stored at low temperature.
1.2 Storage stability of silicone oil in the combination material
The new silicone oil and the original self-used silicone oil were formulated into a combination of polyether with the same formula, and under the same process conditions, foamed to compare the swelling and bubble hole situation, then the combined polyether was injected into a 1-liter glass bottle, placed in a 60-degree water bath, and taken out after 6 hours to cool, and under the same process conditions, foamed again to compare the swelling and bubble hole situation of the products before and after aging. If there is any abnormality, it means that the silicone oil is risky to do the combination material.
Second, the activity of silicone oil evaluation
Process conditions: mold temperature 60 degrees, material temperature 25 degrees, same demolding time. According to the approximate activity of silicone oil given by the manufacturer, the characteristics of silicone oil can be determined by the closed porosity.
1、Without equipment, the activity of silicone oil can be determined by the amount of porosity opener.
2、It is also possible to determine the activity of silicone oil by the assistance of indentation hardness meter.
3、During the activity evaluation: all factors affecting the degree of closed pore should be considered thoroughly to avoid interference.
Three, the tolerance of silicone oil test
1、Different systems, after reducing the amount of silicone oil, test the molding changes.
2、Mold temperature adaptability test.
3、Flowability test.
4、Under the same closed porosity, compare the product vesicle structure and select the silicone oil with more delicate vesicles to improve the processing tolerance during the actual molding production.
IV. Silicone oil VOC contribution test
1、Testing method: VDA 278
2、To compare with other silicone oil, use the same formula except silicone oil, the same process to make samples, and use VDA 278 to compare the test data.
V. Summary
Combination material manufacturers are more cautious to switch silicone oil, but 3W silicone oil is known and recognized by more and more famous combination material manufacturers by virtue of its excellent quality, which I think is inseparable from our strict testing methods.
