Interactive Platform § Living Polymerization of Light Curing Resins
Reaction Principle - Background Description: Photocurable resins can be divided into two major systems: 1. Photocurable resins with acrylics as functional groups and polymerized by free radicals. 2. A photocurable resin polymerized by cationic ions with epoxy groups (oxiranes) as functional groups.
Properties of free radicals: The lifetime of free radicals is very short, only about tens of ns. In other words, the acrylic photocurable resin will generate free radicals to polymerize when exposed to light. When the light is stopped, the free radicals will disappear immediately and no further reaction will be possible.
The properties of cations: light-cured epoxy resins are quite different. The epoxy-based photocurable resin generates cations to polymerize when exposed to light, and the cations do not disappear immediately when the illumination is stopped. The lifetime of cations can be as long as two or three days after the light is stopped. The cations generated during illumination will continue to react within two or three days after the illumination is stopped, and can improve various properties of the cured product. This characteristic is called live polymerization.
Reaction conditions
Pure light-curing: For pure light-curing epoxy resins, only light will trigger a chemical reaction, and cations will be generated. These ions will not undergo active polymerization until the light is stopped, and continue to improve the properties of the resin. Without illumination, no cations will be generated, and living polymerization will not proceed.
Multi-curing system: Some Ultrawide® light-curing epoxy resins are multi-cure systems, which can trigger a cationic chemical reaction by light alone or by heating to trigger a cationic chemical reaction. In this system, the ions induced by irradiation or heating can undergo living polymerization after irradiation or heating.
Experiment § IMD (In Mold Decoration) (3)
At present, Everwide Chemical's research and development direction of related products for IMD technology
1. Anti-inking protective glue: In the process of plastic injection, the high temperature and high pressure of the plastic can easily cause the printed ink to be washed away, resulting in poor finished products. This situation can be started by improving the design of the injection mold, reducing the pressure during discharge, or applying multiple layers of ink to reduce the impact of ink flushing. If UV glue can be used to protect the ink layer first, when the plastic is ejected, the ink can be protected from being washed away, which will be more convenient and cost-effective to achieve the effect.
2. Plastic injection adhesive: For the ink brand and injection plastic (such as PC, ABS, PMMA, etc.) used by the user, we need to develop an adhesive that can effectively help the ink to adhere to the injection material.
3. UV ink: At this stage, most users use solvent-based ink. Although it has a low price, it has a heavy smell and a long waiting time for drying. However, UV ink will be more environmentally friendly and greatly shorten the processing time, which is the current development direction of ink.
4. Customer-based R&D: Customized R&D for the ink adhesion problems faced by customers. There are many successful cases.
─Author: Ms. Miao-Ling, Lin R&D Engineer, Everwide Chemical
Knowledge §How to toughen epoxy resin?
Generally used epoxy resins are too brittle, toughening epoxy resins has always been a hot research topic: 1. Use plasticizers, such as DOP, DINP, etc. 2. Use toughening agents, such as liquid rubber, Dussel type PU, etc. 3. Use modified resins, such as PU modified epoxy resin, sesame oil-modified epoxy resin, etc. 4. Use resins with higher toughness, such as polyether epoxy resins, long-chain aliphatic epoxy resins, etc. 5. Use a curing agent with high toughness, such as polyether-based bisamine, polyamide, etc.
Product introduction § FC094
ULTRAWIDE® FC094 light-curing resin is one of the resin projects successfully developed by Everwide Chemical. It has low curing shrinkage, excellent adhesion, and curing depth. It is especially used for fixing and bonding between metal materials such as iron and aluminum and glass. Under the irradiation of ultraviolet light, the resin reacts rapidly and produces excellent adhesion strength with the metal. At present, it has been used in the fixing of the diamond mirror in the projector and the screw sealing of the hard disk. It has low shrinkage properties and is especially suitable for the adhesion of precise optical positioning.
Living § Source of the problem
Compared to many of my peers, I'm quite a questioner. This personality has something to do with the special training I had in high school. When I was just studying physics in my second year of high school, I couldn't understand anything, and I couldn't solve the problem in a cram school. Later, through the introduction of relatives, my mother helped me find a tutor. This tutor is said to be very famous. He just graduated from Normal University, stayed at the school for a year as a teaching assistant, and reached the internship qualification. (At that time, the graduates of Normal University had to go to middle and high schools to serve as intern teachers for one year before they could obtain the teaching qualification. Usually, only the first-ranked students could stay in Normal University as teaching assistants.) When I met this tutor for the first time, he told me two conditions for him to be a tutor: First, he didn't have time to come to my house to teach me, so I had to go to the library of the Normal University to find him. Second, he didn't have time to prepare textbooks to help me in class, so I had to prepare my own questions and ask him questions. From the point of view of ordinary people, no one would ask for this kind of tutoring. But at that time, in order to improve my physical performance, I could accept any price. Twice a week, I take a bus from Chenggong Middle School in Chengzhong District to the Normal University branch in Muzha District to find tutors when getting out of class ends at 5 o'clock. After eight o'clock in the evening, my father drove to Normal University to drive me home. If you look at the map of Taipei City, you will find that this route has already made a half-circle around Taipei City. The traffic problem can be solved, and the teaching material problem is not difficult to overcome at the beginning. Anyway, I don't know anything. I just sit down, spread out the textbooks, and tell him that he can't understand here and there, and he can talk for a long time until it's time to end the get out of class. Strange to say, after his counseling, it is easy to understand a lot. Gradually, I became able to understand the textbook, and then I was able to read reference books and do exercises by myself. The range of questions asked when being tutored by a tutor also progressed from the content of the textbook to the problem-solving of the reference book. As I progressed, I had fewer and fewer questions and less and less able to make good use of my two-hour tutoring time. I had to desperately prepare a lot of questions. One reference book is not enough, so I made two or three, and I had to make good use of these two hours. After two years of this kind of special training, my grades in "high school physics" are very good and the university entrance exam has also surpassed the high standard by a large margin. I have a good foundation in physics, all thanks to the special teaching method of my tutor in high school, which is to "find the problem yourself". This experience has given me considerable inspiration. After college, my grades were mediocre and not outstanding. But the key exams, whether it is the entrance exam for the master's class or the qualification exam for the doctoral class, I can rank at the top. My good grades also use the method of "discovering the problem by myself". Now I will share this secret with you and I hope you can refer to it and make progress.
─Author: Dr. Ming-Xu, Li Everwide Chemical
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