Gelling phenomenon refers to the phenomenon that resin or coating thickens or agglomerates at a specified temperature and time.
The main causes of resin or paint gelation are as follows:
1. When the shelf life is exceeded, the shelf life of UV resin under good storage conditions does not exceed six months. But it is best to use it within three months.
2. UV resin should be stored in plastic drums or metal drums coated with plastic. Metal ions reduce the activation energy of double bonds in UV resins, and initiate polymerization to cause resin gelation. Therefore, if the plastic layer in the plastic barrel is damaged, the exposed metal layer will cause the resin to gel.
3. Too low storage temperature (below 0℃) will precipitate the polymerization inhibitor in the paint film, causing the resin to self-polymerize and cause the resin to gel.
4. During the storage of UV resin, direct sunlight should be strictly avoided. Otherwise, it is easy to cause resin gelation.
5. The barrel is too full and there is not enough oxygen to inhibit polymerization, which will cause the resin to gel.
Notes on gelation:
1. The viscosity of the resin without diluting monomer is very high, and some users may mistakenly think that the resin has gelled. In fact, it is easy to detect whether the resin is gelled after heating it. The resin that has not been gelled will have good fluidity after heating. .
2. The problem of using UV resin, the detection method and detection index of UV coating film is the same as other coatings, and it varies with the specific application. Various problems will occur during the application of UV coatings. Only gelation during storage has a great relationship with the UV resin itself, other problems can be solved by adjusting the UV coating formula. Because the UV coating is composed of various components, it is also affected by the light source's illumination distance and illumination time. Its coating film performance is the result of various factors. Replacing the same resin with the same formula instantly. Due to the differences in resins of various manufacturers, the performance of the coating film will be changed. The formula needs to be adjusted, but as long as the resin does not gel or gelation occurs in the formulated coating, the coating film The performance can be adjusted by adjusting the formula.
3. There are many reasons for the gelation of UV coatings, not only related to the resin, first of all, you should find whether it is caused by improper storage. Because UV paint contains photosensitizer, its storage conditions are stricter than those of UV resin. It should be stored in a dark place to avoid seeing the light. The photosensitizer used is of poor quality, even if it is stored in a dark place. Will slowly decompose and cause the cured paint to gel.
4. The quality of the monomer is also an important factor affecting storage stability.