Experiment § Problems with pigments in the formulation
In order to identify whether the two-component epoxy resin is evenly mixed, some customers will require us to add pigments to the two-component epoxy resin. In order to identify whether the two-component epoxy resin is evenly mixed, some customers will require us to add pigments to the two-component epoxy resin. If there is uneven mixing, the mixture will appear black and white mixed lines, so when this happens, the user knows to strengthen the mixing. Dyeing the product seems very simple because you only need to put toner or color paste into the formula to complete the dyeing, but dyeing can also be difficult. Some pigments have a pH value, which will be affected by the resin formulation. A customer wanted us to dye the curing agent B agent yellow, so we added a yellow pigment, and the initial color is shown on the left in Figure 1, showing a uniform yellow. However, this sample will turn orange after being left for a period of time, and sedimentation will occur at the bottom (Figure 1 on the right). We have studied many variables and tried many kinds of dispersive wetting agents, but they were not useful, but later we found that the cause of this discoloration is related to the pH value of the epoxy resin amine curing agent, because the amines are alkaline and the pH value is at around 8-9, this is the cause of discoloration. The pH value of the epoxy resin of agent A is about 7~8, if we change the color material into agent A, there will be no problems with discoloration and precipitation.
If an acid anhydride system is selected for the curing agent, the pH will be slightly acidic, and the choice of pigment may have another consideration. The seemingly simple problem of dyeing can sometimes be very confusing, so it is obvious that chemistry is really a subject of many changes!
─Author: Miss. Su-Huan, Li
Activity § Our waste disposal
The wastes produced by Everwide Chemical are all industrial wastes, which can be subdivided into general industrial wastes and hazardous industrial wastes. Some of these wastes can be recycled and reused, for example 55-gallon iron drums, which can be resold to second-hand iron drum manufacturers for cleaning and reuse. Paper, plastics, and metals are also regularly sold to local recyclers. The money collected from these resources will be used as welfare funds for the Welfare Committee. The waste activated carbon of the activated carbon adsorption tower is processed and regenerated by the manufacturer, and the waste solvent used for cleaning is distilled and reused in the factory. There are many types of our business waste, all of which are treated by incineration, and the treatment costs are very different. For example, the mixture of domestic garbage and waste paper that cannot be recycled belongs to general business waste, and the processing fee is about 3~5 yuan/kg. Waste resin is also a general industrial waste because the treatment method is more complicated, the treatment fee is much more expensive, about 20-25 yuan/kg. In addition to the waste in the factory, we also need to pay the Environmental Protection Agency's Resource Recovery Management Fund for the use of packaging materials under 17 liters for the related expenses of recycling outside the factory. Iron packaging materials are about 2 yuan/kg, and plastic packaging materials are about 7-9 yuan/kg. From in-factory to out-of-factory, are we very environmentally friendly?
Knowledge § What does the RTI in the UL card mean?
RTI (Relative thermal index) means that the specified original physical properties (electrical and mechanical properties) of polymer material can be maintained at a temperature of 50% after being placed at a certain temperature for 100,000 hours. Since it is not feasible to perform a test of 100,000 hours (equivalent to 11.4 years), RTI is actually an accelerated thermal aging test of 5,000 to 10,000 hours to infer the maximum temperature that the specified characteristics of the material can withstand in 100,000 hours. Materials that have not applied for RTI registration to accept the thermal aging test will be assumed to have the same RTI value as similar materials. For example, PC (polycarbonate) will automatically be filled with 80°C, and epoxy resin will be filled with 90°C. RTI is the relative scale of the highest continuous use temperature, and the value is determined by the specified characteristics. Therefore, the value may not be related to the actual application. For example, RTI is not suitable for evaluating long-term adhesion properties, durability against cracks, and the airtightness of caulking materials. Some applications are only high and low-temperature cycles, not long-term high temperatures, and there is no need for this assessment. There are many cases and it is believed that it is more meaningful to use actual items to evaluate the accelerated experiment than to simply look at the RTI value.
Living § what happened 20 years ago
Twenty years ago, I was a graduate student and often went to my uncle’s factory to do experiments on holidays. My uncle built a small second-floor laboratory in the corner of the factory, and the tables, medicine cabinets, and ventilation cabinets inside were all nailed with wood by my uncle. The main equipment is 2 ovens and viscometer, and there is a sink for washing hands in the corner. I often do experiments there and sometimes it’s not over until midnight, but there is no toilet there, so if I want to go to the toilet, I have to go down the stairs to the next office, which is very troublesome. One day I couldn't help it, so I sneaked up on my tiptoes to pee into the sink in the corner, and then rushed with the tap water it was a lot easier and easier! After eating, every night when I want to go to the toilet, I first go to the window to see if there is anyone downstairs, and then I ran to the sink to go to the toilet. The advantage of this method of going to the toilet is convenience, but the disadvantage is that it makes people nervous. One night, my uncle and I did an experiment together, and he said to me: We are both boys, and I want to tell you a secret. If you want to go to the toilet at night, you don't have to be so troublesome, just go to the sink, and I have been doing this for many years. As he spoke, he really demonstrated. I opened my eyes and exclaimed: Really? I didn't admit to my uncle that I had done this a long time ago. Thinking about it afterward, I'm really hypocritical. Twenty years have passed in a blink of an eye, and now the toilet is outside the laboratory, but no experiments are done at night. Thinking of this past, I miss the sink that I shared with my uncle infinitely. The picture on the left shows Huixu taking a recent photo of his uncle and it is obvious that he is healthy and cheerful, so this article only pays tribute to his uncle and his time. Want to know more stories from twenty years ago?
Please click the following link: www.everwide.com.tw/download/memory.pdf
─Author: Dr. Ming-Xu, Li
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