No matter how we entered the polyurethane industry, we are proud that polyurethane materials are the best among many chemical synthetic materials. However, it is difficult to actually do it. Not only are the products changing, but the influencing factors are also changing. There are often the same combination of materials that can produce qualified products under normal conditions when producing products, but problems may arise due to fluctuations in ambient temperature. When the ambient temperature is high, the material rises too quickly, fearing that the injection time is not enough, or the curing is too fast and the foam develops. Did not do well. When the ambient temperature is low, more material needs to be injected, and the curing is slow, causing problems such as under-maturation, brittle foam, and adhesion. What is even more tragic is that the foam shrinks after a while. What is the reason? Is it due to the operation? Do workers need to improve? Those with experience can make changes accordingly. But the fundamental reason is that our material is too delicate. Do you still remember how we seasoned? Know how to theoretically calculate the isocyanate index. When mixing white ingredients, mix the white ingredients according to the ratio of 1 to 1.05:1 of black and white ingredients, and then do a small test.
The foaming time period is measured, and the wire drawing is measured at the end. What does wire drawing mean? It means that the polyurethane structure is formed and the gel begins. Since the structure is viscoelastic, the foam begins to be elongated until it solidifies, but at this point the foam The changes are not over. When the density is high enough and the ambient temperature is high enough, the foam can mature by its own heat release and no longer deform. It would be tragic if this were not the case. This characteristic of polyurethane limits its application and development.
People call all materials in which isocyanate participates in the reaction polyurethane. No one has been able to synthesize and name the reaction between isocyanate and urethane and the reaction with allophanate. This is because there is no catalyst that can continue to react with isocyanate while catalyzing the formation of urethane. Existing tertiary amine catalysts and organometallic catalysts only solve the problem in the balance of forming polyurethane foaming gel. Now we are fortunate to have found or synthesized a class of compounds called polytertiary amine formates. As a catalyst, they show high catalytic activity for multi-stage and self-trimerization of isocyanates and urethanes. .
The structures used as catalysts include tertiary amines and organometallic salts. In the application of foaming, the comprehensive effect is manifested in the first-level reaction of isocyanate: such as the generation of urethane, and the formation of CO2 with water, substituted urea, which has weak activity, and the deep reaction of isocyanate is the second-level multi-level auto-reaction. The polymerization reaction has strong activity, which is reflected in the slow foaming when used alone. It can be matured after curing without drawing. If used together with the tertiary amine foaming catalyst, the initial development shows that the tertiary amine is active and has good foam fluidity in the mid-term. In the later stage, it can be cured with basically no wire drawing and will be matured after curing.
The emergence of this technical catalyst has increased the target product catalyzed from the first-level reaction product carbamate to multi-level reaction products and its own trimerization products. Not only the final quality of the foam has changed, but also the foaming Changes have also been observed in the process, and the evaluation methods have also changed. For example, we found that the first-level and multi-level reactions of isocyanate are carried out simultaneously until the foaming reaches the end point. The pressure in all directions is the same, and the driving force base is the same, and it needs to be measured as before. Is it wire drawing? It promotes fluidity, does the foaming time still need to be that long? It promotes maturation, is there still such a strict requirement on the curing time? The foam is already full before maturing, and there is no need to overfill, while the small test is free to grow The bubble height may not be enough; materials that mature slowly must be overfilled because as long as they are not matured yet, a large amount of materials can be filled. One is to increase the heat to speed up the aging, and the other is to fill the mold. When the material that matures during curing shows that it is full, more material will be squeezed out. In addition to saving raw materials, this also brings a lot of benefits. But it is not a panacea. As a catalyst, it still needs to be used in conjunction with a tertiary amine catalyst with good foaming activity to be perfect.
I have limited experience in ingredients, so I would like to invite experts and big names in the industry to help me with ingredients.��Your rich experience and ingenuity experience this system as a catalyst for changes in ingredients and qualitative changes in products. We hope to make the preparation of your combined materials easier, simpler, more stable and more fun, so that you can have greater tolerance in the production operations of your products, and all the products produced will be super good. Let’s all work hard and innovate boldly and work hard for China’s polyurethane industry to move to the forefront of the world and become a technological powerhouse. Seek change for your own strength. All actions are impermanent, and the changes in the sum of all things are the result of the causal action of two or more elements. Therefore, treating everything with a change-oriented mentality will maintain a prepared and peaceful mentality.
Note 1: To achieve the desired effect using the catalyst of this system, the isocyanate index must be excessive. If high temperature resistance is to be produced, the retardant fuel must be multiplied according to the height of the temperature resistance and the flame retardant level.
