Everwide Newsletter No.136

Light-curing resins can be divided into two major systems: cationic polymerized epoxy resin system and free radical polymerized acrylic resin system. The former has better temperature resistance, chemical resistance, and ring test effect, and is often used in the adhesion of electronic components. Whenever we come into contact with a case about a cationic system, we always ask the customer first: Is your company’s equipment a "point light source" or a "flat light source"? Point light sources can usually project very high energy in a short time and within a small range, and can quickly carry out the light-curing reaction. The illumination range of the flat light source is relatively wide, and the unit illuminance is relatively weak, so most of them need to cooperate with the conveyor belt equipment to provide the energy required for the reaction. This seemingly inconspicuous problem will greatly affect the design of the cationic system formulation. The reaction rate of epoxy resin cations is not as fast as the free radical system of acrylic. If the process of exposure and curing is irradiated with a flat light source and conveyor equipment, the photocuring reaction will vary in speed due to the position of the resin. Take figure 2 as an example, first enter the conveyor belt, where the resin starts to react (position A) where it is exposed to light, and the phenomenon of curing shrinkage occurs. This shrinking phenomenon will guide the uncured liquid resin to the front position, causing bubbles or holes in the rear exposed position (position B). In contrast, point light sources can be exposed at the same time before and after, so there will be no such phenomenon (Figure 4). Of course, a few of the test pieces in the customer's application photos will be large and thick. However, this experiment still has considerable value, enough to help us think about the reasons why the width, thickness, and shape of the glue applied after exposure to many light-curing resins will change.

—Author：Ms. Shu-Ting, Yang

Some of our products need to be stored at a low temperature. If the environment exceeds a certain temperature for a long time, there is a risk of deterioration. However, the local refrigerated home delivery service in Taiwan has developed very well, and the goods received by customers can be maintained at a low temperature. However, the conditions of overseas transportation vary from place to place, and customers often question: how do you know that the temperature during the transportation is not too high and ensure product quality? For packaging, we use an incubator and put a cold storage bag or dry ice in it, seal it properly and ship it. When a new transportation route is adopted, we will first use a temperature recorder to collect temperature changes throughout the entire process, as a reference for subsequent packaging and transportation (upper left). However, it will take some time for the recorder to recycle and judge, so it cannot actually be used every time it is shipped. In order to give customers more confidence in the quality of the transportation, we purchased temperature record stickers, which will gradually be used on the packaging that requires low-temperature storage and overseas shipping. Put the sticker on the inner side of the incubator cover. Once the temperature exceeds the marked temperature during transportation, the recording sticker will irreversibly change color, which can be easily identified by customers and increase the reliability of product quality (Lower left figure).

—Author： Mrs. Wen-Chao, Shi

Generally, the one-component epoxy resins we commonly use have the following advantages. The first point is that the one-component epoxy resin does not need to be mixed before use, so the processing process can be simplified. The second point is that one-component epoxy resin does not need to weigh the AB ratio, so it can reduce the chance of error. The third point is that the cost of dispensing equipment for one-component epoxy resins is lower than that of two-component epoxy resins. The fourth point is that one-component epoxy resin basically has no margins and waste. The fifth point is that there is no operating time limit for one-component epoxy resins. The disadvantages of one-component epoxy resins are mostly related to storage conditions. For example 1. One-component epoxy resin cannot be cured at room temperature, so it must be heated and baked. 2. The shelf life of one-component epoxy resin may be relatively short. 3. One-component epoxy resin may need to be refrigerated or even frozen. The formulations of the single-component epoxy resin and the two-component epoxy resin are not the same. After curing, the properties have their own characteristics, and it is difficult to make two versions with exactly the same properties.

"No criticism, no blame, no complaint" This is the first law that impresses the Carnegie class most. We all take this as a warning, hoping that we will not become people who criticize, blame, and complain. Criticism and complaints are like bad breath. The person concerned will not realize that his actions will make others feel uncomfortable. And these three things often make work morale low and even make many people feel bad as soon as they work. In order to keep ourselves away from such vices, we should put ourselves in consideration for others and know how to review ourselves all the time. For example, sometimes we complain that the data prepared by our colleagues is not complete and difficult to read. So at this time, we should first think from the position of the colleague who is doing the data, and consider whether he has too much work so that they cannot completely organize the data? Or is it because he doesn't have enough tools, or the method is wrong? Think about it from another angle, we might be able to help this colleague find a suitable method for him to organize information. When we change our attitude, we will not criticize, blame and complain, so there will be no quarrels and can enhance friendship. "The Analects of Confucius-Wei Ling gong," said: "Being self-reliant, and blaming others is far from resentment." If we can reflect on ourselves in everything, then we will blame others less, and nor will unpleasant things happen with people. Carnegie's teaching of "no criticism, no blame, no complaint" can serve as a reminder. If we want to make more friends, we must not start everything with criticism, blame, and complaint. If we do something wrong today, don't forget to review whether we are wrong or need improvement. Criticism, blame, and complaint not only can't solve the problem but also make people around us far away. This should not be the result everyone wants! Only by keeping these words in mind and implementing them thoroughly can we continue to make progress and make ourselves better!

—Author： Ms. Heng-Rong, Li