The general evaluation method of high rebound silicone oil
High rebound sponge is ubiquitous in our lives, and silicone oil is an indispensable component of the sponge, it is used to regulate the pore structure, play the role of emulsification, nucleation, reduce surface tension, although the amount is small, but it is vital, how to professionally evaluate it, technical workers have their own methods, how to select a good product, I’ll share some of our evaluation of silicone oil experience.
I. Stability test of silicone oil
1.1 Storage stability test of silicone oil
Storage stability of silicone oil at low temperature
Silicone oil will be 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 not obvious, take out the silicone oil and the silicone oil at room temperature to do a comparative experiment to see whether the silicone oil closure and the structure of the vesicle is normal, if there is any abnormality, it means that this type of silicone oil can not be stored at low temperatures.
1.2 Storage Stability of Silicone Oil in Combination Materials
The new silicone oil and the original self-use of silicone oil with the same formula into a combination of polyether, under the same process conditions, foaming comparison of the expansion and vesicle situation, and then will be equipped with a combination of polyether were injected into a 1-liter glass bottle, placed in a 60-degree water bath, 6 hours after taking out the cooling, in the same kind of conditions, and then foaming, comparison of aging before and after the products of the expansion and vesicle situation, such as anomalies, it is shown that the If there is any abnormality, it means that the silicone oil is risky to be used as combination material.
Second, the activity of silicone oil evaluation
Process conditions: mold temperature of 60 degrees, material temperature of 25 degrees, the same demolding time. According to the approximate silicone oil activity given by the manufacturer, the silicone oil properties are determined by the degree of closure.
1, without equipment, can be used to open the amount of pore agent, to determine the activity of silicone oil.
2, can also be assisted by indentation hardness meter to determine the activity of silicone oil.
3, activity assessment period: the various factors affecting the degree of occlusion should be considered thoroughly to avoid interference.
Third, the tolerance test of silicone oil
1, different systems, reduce the amount of silicone oil, test molding changes.
2, molding temperature adaptability test.
3, fluidity test.
4, the same degree of occlusion, compare the product bubble structure, select the bubble more delicate silicone oil, in order to improve the actual molding production processing tolerance.
IV. Silicone oil VOC contribution test
1、Test method: VDA 278
2, and other silicone oil for comparison, with the exception of silicone oil, the same formula, the same process to produce samples, with VDA 278 comparison test data.
V. Summary
Combination of material manufacturers switch silicone oil is more cautious, but 3W silicone oil with excellent quality, more and more well-known combination of material manufacturers are familiar with the recognition, I think this and our strict testing methods are inseparable.
After all, polyurethane is also a chemical industry, and these problems actually involve every raw material. Where to participate in the chemical reaction of each raw material is very important, whether it is the main material or a small material have its unique effect, so if one of the raw materials in the chemical reaction produced a change, then it will naturally in the foaming process from the sponge on the embodiment of the bubble, which is one of the most basic principles, the embodied problem if it is not pathological, then it is a revelation; if it is a pathology then We have to consider what to take to solve it; if it is a revelation to us then we have to consider how to utilize it or perfect it, we should know that a lot of evolution and invention are in the revelation of the development of up.
For example: we all know that the current domestic slow rebound polyether manufacturers have Shanghai Gaoqiao 2000, Nanjing Jinpu 1070, on the two slow rebound polyether, although its hydroxyl value are 240, however, in the actual production of their respective chemical activity is very different from each other and have their own characteristics, a few years ago, the 2000 and 1070 need not be adjusted in other raw materials can be used in place of each other, however, a few years later today they have formed a new generation of polymerization. A few years later today they have formed their own characteristics, and can no longer be used as is to replace each other.
Of course, the domestic production of slow-rebound polyether is far more than these two manufacturers, so each slow-rebound sponge manufacturers use raw materials is difficult to unify, including a variety of small materials. This has formed each enterprise has its own formula, on the slow rebound polyether in terms of porous better and better stability. Porosity better slow rebound polyether in the production process, the amount of pore opener is appropriate to a little less, and the amount of silicone oil (stabilizer) compared to the amount of it should be appropriate to increase a little bit; on the contrary, if you use the slow rebound polyether is more stable or more closed-air type, then the amount of pore opener in the production process should be a little bit more, and silicone oil should be a little bit down.
So how to determine the amount of pore opener and silicone oil added? In the polyurethane industry due to the slow rebound sponge and other sponges are different, such as ordinary sheep high rebound sponge no matter how many manufacturers, but their production formula can be said to be similar, or even basically the same, while the slow rebound sponge is different from its formulations are changing, so to pattern positioning of the amount of pore-opening agent and silicone oil is absolutely impossible, but no matter how the basic principle is still not far from Which, no matter how to change as long as you familiarize yourself with the rules of good grasp of its operation can also be handy, the amount of pore opener regardless of the density of the slow rebound sponge you send, as long as the sponge sent at the end of the reaction to see the level of the sponge to put a little gas can be put, but put the bubbles can not be too big, the bigger the bubbles pores will be coarser, which also indicates two problems, a silicone oil is insufficient to increase a certain percentage of the silicone oil, two if the cutting of cotton is not enough, the silicone oil will not be enough. Silicone oil, two if the cut sheep body to see the pores of normal, then the amount of pore-opening agent additive is on the high side, should reduce the amount of pore-opening agent additive.
